VRML97, ISO/IEC 14772-1:1997 -- Annex B, Java Platform Scripting Reference

#

#
The Virtual Reality Modeling Language

#
Annex B
(normative)

#
Java platform scripting reference

###

## B.1 Introduction

This annex describes the Java platform classes and methods that enable Script nodes (see 6.40, Script) to interact with VRML scenes. See 4.12, Scripting, for a general description of scripting languages in ISO/IEC 14772. Note that support for the Java platform is not required by ISO/IEC 14772, but any access of the Java platform from within VRML Script nodes shall conform with the requirements specified in this annex.

B.1 Introduction
B.2 Platform
B.3 Supported protocol in the Script node's url field
B.3.1 url field
B.3.2 File extension
B.3.3 MIME type
B.4 EventIn handling
B.4.1 Description
B.4.2 Parameter passing with event objects
B.4.3 processEvents() and processEvent() methods
B.4.3.1 processEvents() method
B.4.3.2 processEvent() method
B.4.4 eventsProcessed() method
B.4.5 shutdown() method
B.4.6 initialize() method
B.5 Accessing fields and events
B.5.1 Accessing fields, eventIns and eventOuts of the script
B.5.2 Accessing fields, eventIns and eventOuts of other nodes
B.5.3 Sending eventOuts or eventIns
B.6 Exposed classes and methods for nodes and fields
B.6.1 Introduction
B.6.2 Field class and ConstField class
B.6.3 Array handling
B.6.3.1 Format
B.6.3.2 Constructors and methods
B.6.4 Node class
B.6.5 Browser class
B.6.6 User-defined classes and packages
B.6.7 Standard Java platform packages
B.7 Exceptions
B.8 Examples
B.9 Class definitions
B.9.1 Class hierarchy
B.9.2 VRML packages
B.9.2.1 vrml package
B.9.2.2 vrml.field package
B.9.2.3 vrml.node package
B.10 Example of exception class

## B.2 Platform

The Javatm platform is an object-oriented, hardware and operating system independent, multi-threaded, general-purpose application environment developed by Sun Microsystems, Inc. The Java platform consists of the language, the virtual machine, and a set of core class libraries. A conforming Java platform implements all three components according to their specifications. See 2.[JAVA] for a description of the language, the virtual machine, and the three core classes java.lang, java.util, and java.io. The other core class libraries, which are not used in this annex, are described in E.[JAPI].

## B.3 Supported protocol in the script node's url field

### B.3.1 url field

The url field of the Script node may contain URL references to Java bytecode as illustrated below:

        Script {
          url "http://foo.co.jp/Example.class"
          eventIn SFBool start
        }

### B.3.2 File extension

The file extension for Java bytecode is `.class`.

### B.3.3 MIME type

The MIME type for Java bytecode is defined as follows:

        application/x-java

## B.4 EventIn handling

### B.4.1 Description

Events to the Script node are passed to the corresponding Java platform method (processEvents() or processEvent()) in the script. The script is specified in the url field of the Script node.

For a Java bytecode file specified in the url field, the following three conditions hold:

1. it shall contain the class definition whose name is exactly the same as the body of the file name
2. it shall be a subclass of the Script class (see B.9.2.3, vrml.node package)
3. it shall be declared as a "public" class

For example, the following Script node has one eventIn whose name is start.

        Script {
          url "http://foo.co.jp/Example1.class"
          eventIn SFBool start
        }

This node points to the script file Example1.class. Its source (Example1.java) looks like this:

        import vrml.*;
        import vrml.field.*;
        import vrml.node.*;

        public class Example1 extends Script {
            ...
            // This method is called when any event is received
            public void processEvent(Event e){
               // ... perform some operation ...
            }
        }

In the above example, when the start eventIn is sent the processEvent() method receives the eventIn and is executed.

### B.4.2 Parameter passing with Event objects

When a Script node receives an eventIn, a processEvent() or processEvents() method in the file specified in the url field of the Script node is called, which receives the eventIn as a Java platform object (Event object, see B.4.3, processEvents() and processEvent() methods).

The Event object has three fields of information associated with it: name, value, and timestamp, whose values are passed by the eventIn. These can be retrieved using the corresponding method on the Event object.

       public class Event implements Cloneable {
          public String getName();
          public ConstField getValue();
          public double getTimeStamp();
          // other methods ...
       }

Suppose that the eventIn type is SFXXX and eventIn name is eventInYYY, then

1. getName() shall return the string "eventInYYY "
2. getValue() shall return ConstField containing the value of the eventIn
3. getTimeStamp() shall return a double (in seconds) containing the timestamp when the eventIn occurred (see 4.11, Time)

In the example below, the eventIn name is start and the eventIn value is cast to ConstSFBool. Also, the timestamp for the time when the eventIn occurred is available as a double. These are passed as an Event object to the processEvent() method:

        public void processEvent(Event e){
            if(e.getName().equals("start")){
                  ConstSFBool v = (ConstSFBool)e.getValue();
                  if(v.getValue()==true){
                       // ... perform some operation with e.getTimeStamp()...
                  }
             }
        }

### B.4.3 processEvents() and processEvent() methods

#### B.4.3.1 processEvents() method

Authors can define a processEvents() method within a class that is called when the script receives some set of events. The prototype of the processEvents() method is `public void processEvents(int count, Event events[]);`

count indicates the number of events delivered. events is the array of events delivered. Its default behaviour is to iterate over each event, calling processEvent() on each one as follows:

        public void processEvents(int count, Event events[])
        {
            for (int i = 0; i < count; i++){
                processEvent(events[i]);
            }
        }

Although authors might change this operation by giving a user-defined processEvents() method, in most cases, they only change the processEvent() method and the eventsProcessed() method as described below.

When multiple eventIns are routed from a single node to a single Script node and eventIns which have the same timestamp are received, processEvents() receives multiple events as an event array. Otherwise, each incoming event invokes separate processEvents().

For example, the processEvents() method receives two events in the following case, when the TouchSensor is activated:

        Transform {
          children [
            DEF TS TouchSensor {}
            Shape { geometry Cone {} }
          ]
        }
        DEF SC Script {
          url "Example.class"
          eventIn SFBool isActive
          eventIn SFTime touchTime
        }
        ROUTE TS.isActive  TO SC.isActive
        ROUTE TS.touchTime TO SC.touchTime

#### B.4.3.2 processEvent() method

Authors can define a processEvent() method within a class. The prototype of the processEvent() is `public void processEvent(Event event);`

Its default behaviour is no operation.

### B.4.4 eventsProcessed() method

Authors may define an eventsProcessed() method within a class that is called after some set of events has been received. This allows Script nodes that do not rely on the ordering of events received to generate fewer events than an equivalent Script node that generates events whenever events are received (see B.4.3.1, processEvents() method).

The prototype of the eventsProcessed() method is `public void eventsProcessed();`

Its default behaviour is no operation.

### B.4.5 shutdown() method

Authors may define a shutdown() method within the Script class that is called when the corresponding Script node is deleted or the world containing the Script node is unloaded or replaced by another world (see 4.12.3, Initialize() and shutdown()).

The prototype of the shutdown() method is `public void shutdown();`

Its default behaviour is no operation.

### B.4.6 initialize() method

Authors may define an initialize() method within the Script class that is called before the browser presents the world to the user and before any events are processed by any nodes in the same VRML file as the Script node containing this script (see 4.12.3, Initialize() and shutdown()). The various methods of the Script class such as getEventIn(), getEventOut(), getExposedField(), and getField() are not guaranteed to return correct values before the initialize() method has been executed. The initialize() method is called once during the life of the Script object.

The prototype of the initialize() method is `public void initialize();`

Its default behaviour is no operation. See Example2.java in B.5.1 for an example of a user-specified initialize() method.

## B.5 Accessing fields and events

### B.5.1 Accessing fields, eventIns and eventOuts of the script

The fields, eventIns, and eventOuts of a Script node are accessible from its corresponding Script class. Each field defined in the Script node is available to the Script class by using its name. Its value can be read-from or written-into. This value is persistent across function calls. EventOuts defined in the Script node can be read. EventIns defined in the Script node can be written to.

Accessing the fields of the Script node can be done by using the following three types of Script class methods:

1. `Field getField(String fieldName)`
   is the method to get the reference to the Script node's field whose name is fieldName. The return value can be converted to the appropriate subclass of the Field class, (see B.6.2, Field class and ConstField class).
2. `Field getEventOut(String eventOutName)`
   is the method to get the reference to the Script node's eventOut whose name is eventOutName. The return value can be converted to the appropriate subclass of the Field class, (see B.6.2, Field class and ConstField class).
3. `Field getEventIn(String eventInName)`
   is the method to get the reference to the Script node's eventIn whose name is eventInName. The return value can be converted to the appropriate subclass of the Field class, (see B.6.2, Field class and ConstField class). EventIn is a write-only field. When the getValue() method is invoked on a Field object obtained by the getEventIn() method, the return value is unspecified.

When the setValue(), set1Value(), addValue(), insertValue(), delete() or clear() methods are invoked on a Field object obtained by the getField() method, the new value is stored in the corresponding VRML node's field (see also B.6.2, Field class and ConstField class, and B.6.3, Array handling). In the case of the set1Value(), addValue(), insertValue() or delete() methods, all elements of the VRML node's field are retrieved, then the value specified as an argument is set, added, inserted, deleted (as appropriate) to/from the elements, and then stored as the elements in the corresponding VRML node's field. In the case of the clear() method, all elements of a VRML node's field are cleared (see the definition of the clear() method).

When the setValue(), set1Value(), addValue(), insertValue(), delete() or clear() methods are invoked on a Field object obtained by the getEventOut() method, the call generates an eventOut in the VRML scene (see also B.6.2, Field class and ConstField class, and B.6.3, Array handling). The effect of this eventOut is specified by the associated Route(s) in the VRML scene. In the case of the set1Value(), addValue(), insertValue() or delete() methods, all elements of the VRML node's eventOut are retrieved, then the value specified as an argument is set, added, inserted or deleted (as appropriate) to/from the elements, then stored as the elements in the corresponding VRML node's eventOut, and then the eventOut is sent. In the case of the clear() method, all elements of VRML node's eventOut are cleared and an eventOut with zero elements is sent (see the definition of the clear() method).

When the setValue() or clear() methods are invoked on a Field object obtained by the getEventIn() method, the call generates an eventIn to the Script node. When the set1Value(), addValue(), insertValue() or delete() methods are invoked on a Field object obtained by the getEventIn() method, the exception (InvalidFieldChangeException) is thrown.

For example, the following Script node (Example2) defines an eventIn start, a field state, and an eventOut on. The method initialize() is invoked before any events are received, and the method processEvent() is invoked when start receives an event:

        Script {
          url      "Example2.class"
          eventIn  SFBool start
          field    SFBool state TRUE
          eventOut SFBool on
        }

Example2.java:

        // Example2 toggles a persistent field variable "state" in the VRML
        // Script node each time an eventIn "start" is received, then sets
        // eventOut "on" equal to the value of "state"
        import vrml.*;
        import vrml.field.*;
        import vrml.node.*;

        public class Example2 extends Script {
            private SFBool state; // field
            private SFBool on;    // eventOut

            public void initialize(){
                state = (SFBool) getField("state");
                on = (SFBool) getEventOut("on");
            }

            public void processEvent(Event e){
                if(state.getValue()==true){
                    on.setValue(false); // set false to eventOut 'on'
                    state.setValue(false);
                }
                else {
                    on.setValue(true);  // set true to eventOut 'on'
                    state.setValue(true);
                }
            }
        }

### B.5.2 Accessing fields, eventIns and eventOuts of other nodes

If a script program has an access to a node, any eventIn, eventOut or exposedField of that node is accessible by using the getEventIn(), getEventOut() or getExposedField() method defined in the node's class (see B.6.4, Node class).

The typical way for a Script node to have an access to another VRML node is to have an SFNode field which provides a reference to the other node. The following Example3 shows how this is done:

        DEF SomeNode Transform {}
        Script {
          field SFNode node USE SomeNode # SomeNode is a Transform node
          eventIn SFVec3f pos            # new value to be inserted in
                                         #   SomeNode's translation field
          url "Example3.class"
        }

Example3.java:

        import vrml.*;
        import vrml.field.*;
        import vrml.node.*;

        public class Example3 extends Script {
            private SFNode node;   // field
            private SFVec3f trans; // translation field captured from remote
                                   // Transform node

            public void initialize(){
                node = (SFNode) getField("node");
            }

            public void processEvent(Event e){
                // get the reference to the 'translation' field of the Transform node
                trans = (SFVec3f)((Node) node.getValue()).getExposedField("translation");
                // reset translation to value given in Event e, which is eventIn pos
                // in the VRML Script node.
                trans.setValue((ConstSFVec3f)e.getValue());
            }
        }

### B.5.3 Sending eventOuts or eventIns

Assume that the thread which executes processEvent() (or processEvents()) is called 'main' thread and any other thread spawned by the Script, except for the 'main' thread, is called 'sub' thread. Sending eventOuts/eventIns in the 'main' thread follows the model described in 4.10.3, Execution model, and sending eventOuts/eventIns in any 'sub' thread follows the model described in 4.12.6, Asynchronous scripts.

In the 'main' thread: Calling one of the setValue(), set1Value, addValue(), insertValue(), clear() or delete() methods on an eventOut/eventIn sends that event at that time. Calling the methods multiple times during one execution of the thread still only sends one event which corresponds to the first call of the method. All other calls are ignored. The event is assigned the same timestamp as the initial event which caused the main thread to execute.

In the 'sub' thread: Calling one of the setValue(), set1Value, addValue(), insertValue(), clear() or delete() method on an eventOut/eventIn sends that event at that time. Calling the methods multiple times during one execution of the thread sends one event per call of the method. The browser assigns the timestamp to the event.

Note: sending eventIns is ordinarily performed by the VRML scene, not by Java platform scripts. Exceptions are possible as specified in B.5.1, Accessing fields, eventIns and eventOuts of the script.

## B.6 Exposed classes and methods for nodes and fields

### B.6.1 Introduction

Java platform classes for VRML are defined in the packages: vrml, vrml.node and vrml.field.

The Field class extends the Java platform's Object class by default; thus, Field has the full functionality of the Object class, including the getClass() method. The rest of the package defines a "Const" read-only class for each VRML field type, with a getValue() method for each class; and another read/write class for each VRML field type, with both getValue() and setValue() methods for each class. A getValue() method converts a VRML type value into a Java platform type value. A setValue() method converts a Java platform type value into a VRML type value and sets it to the VRML field.

Some methods are listed as "throws exception," meaning that errors are possible. It may be necessary to write exception handlers (using the Java platform's catch() method) when those methods are used. Any method not listed as "throws exception" is guaranteed to generate no exceptions. Each method that throws an exception includes a prototype showing which exception(s) can be thrown.

### B.6.2 Field class and ConstField class

All VRML data types have equivalent Java platform classes. The Field class is the root of all field types.

        public abstract class Field implements Cloneable {
            // methods
        }

This class has two types of subclasses: read-only classes and read/write classes

1. Read-only classes
   These classes support the getValue() method. Some classes support additional convenience methods to get value(s) from the object.
   ConstSFBool, ConstSFColor, ConstMFColor, ConstSFFloat, ConstMFFloat, ConstSFImage, ConstSFInt32, ConstMFInt32, ConstSFNode, ConstMFNode, ConstSFRotation, ConstMFRotation, ConstSFString, ConstMFString, ConstSFVec2f, ConstMFVec2f, ConstSFVec3f, ConstMFVec3f, ConstSFTime, ConstMFTime
2. Read/write classes
   These classes support both getValue() and setValue() methods. If the class name is prefixed with MF (meaning that it is a multiple valued field class), the class also supports the set1Value(), addValue() and insertValue() methods. Some classes support additional convenience methods to get and set value(s) from the object.

   SFBool, SFColor, MFColor, SFFloat, MFFloat, SFImage, SFInt32, MFInt32, SFNode, MFNode, SFRotation, MFRotation, SFString, MFString, SFVec2f, MFVec2f, SFVec3f, MFVec3f, SFTime, MFTime

The VRML Field class and its subclasses have several methods to get and set value(s): getSize(), getValue(), get1Value(), setValue(), set1Value(), addValue(), insertValue(), clear(), delete() and toString(). In these methods, getSize(), get1Value(), set1Value(), addValue(), insertValue(), clear() and delete() are only available for multiple value field classes (MF classes).

3. `getSize()`
   is the method to return the number of elements of each multiple value field class (MF class).
4. `getValue()`
   is the method to convert a VRML type value into a Java platform type value and return it.
5. `get1Value(int index)`
   is the method to convert a single VRML type value (index-th element of an array) and return it as a single Java platform type value. The index of the first element is 0. Attempting to get an element beyond the length of the element array throws an exception (ArrayIndexOutOfBoundsException).
6. `setValue(value)`
   is the method to convert a Java platform type value into a VRML type value and copy it to the target object.
7. `set1Value(int index, value)`
   is the method to convert from a Java platform type value to a VRML type value and copy it to the index-th element of the target object. The index of the first element is 0. Attempting to set an element beyond the length of the element array throws an exception (ArrayIndexOutOfBoundsException).
8. `addValue(value)`
   is the method to convert from a Java platform type value to a VRML type value and append it to the target object, thus adding an element.
9. `insertValue(int index, value)`
   is the method to convert from a Java platform type value to a VRML type value and insert it as a new element at the index-th position, thus adding an element. The index of the first element is 0. Attempting to insert the element beyond the length of the element array throws an exception (ArrayIndexOutOfBoundsException).
10. `clear()`
    is the method to clear all elements in the target object so that it has no more elements in it.
11. `delete(int index)`
    is the method to delete the index-th element from the target object, thus decreasing the length of the element array by one. The index of the first element is 0. Attempting to delete the element beyond the length of the element array throws an exception (ArrayIndexOutOfBoundsException).
12. `toString()`
    is the method to return a String containing the VRML utf8 encoded value (or values) of the equivalent of the field. In the case of the SFNode(ConstSFNode) and MFNode (ConstMFNode),
    - SFNode(ConstSFNode): the method returns the VRML utf8 string that, if parsed as the value of an SFNode field, would produce this node. If the browser is unable to reproduce this node, the name of the node followed by the open brace and close brace shall be returned. Additional information may be included as one or more VRML comment strings.
    - MFNode(ConstMFNode): the method returns the VRML utf8 string that, if parsed as the value of a MFNode field, would produce this array of nodes. If the browser is unable to reproduce this node, the name of the nodes followed by the open brace and close brace shall be returned. Additional information may be included as one or more VRML comment strings

See also B.5.1, Accessing fields, eventIns and eventOuts of the Script, B.6.3, Array handling, B.6.4, Node class, and B.9.2.1, vrml package, for each class' methods definition.

### B.6.3 Array handling

#### B.6.3.1 Format

Some constructors and other methods of the field classes take an array as an argument.

1. A single-dimensional array

   Some constructors and other methods of the following classes take a single-dimensional array as an argument. The array is treated as follows:

   1. ConstSFColor, ConstMFColor, SFColor and MFColor

          float colors[]

      colors[] consists of a set of three float-values (representing red, green and blue).

   2. ConstSFRotation, ConstMFRotation, SFRotation and MFRotation

          float rotations[]

      rotations[] consists of a set of four float-values (representing axisX, axisY, axisZ and angle).

   3. ConstSFVec2f, ConstMFVec2f, SFVec2f and MFVec2f

          float vec2s[]

      vec2s[] consists of a set of two float-values (representing x and y).

   4. ConstSFVec3f, ConstMFVec3f, SFVec3f and MFVec3f

          float vec3s[]

      vec3s[] consists of a set of three float-values (representing x, y and z).

   5. ConstSFImage and SFImage

          byte pixels[]

      pixels[] consists of 2-dimensional pixel image. The ordering of the individual components for an individual pixel within the array of bytes will be as follows:

           # Comp.   byte[i]  byte[i + 1] byte[i + 2] byte[i + 3]

           ------- ---------- ---------- ----------- -----------

              1    intensity1 intensity2  intensity3 intensity4

              2    intensity1   alpha1    intensity2  alpha2

              3       red1      green1      blue1      red2

              4       red1      green1      blue1     alpha1

      The order of pixels in the array are to follow that defined in 5.5, SFImage. byte 0 is pixel 0, starting from the bottom left corner.

2. A single integer and a single-dimensional array

   Some constructors and other methods take a single integer value (called size) and a single-dimensional array as arguments: for example, MFFloat(int size, float values[]). The size parameter specifies the number of valid elements in the array, from 0-th element to (size - 1)-th element, all other values are ignored. This means that the method may be passed an array of length size or larger. The same rule for a single-dimensional array is applied to the valid elements.

3. An array of arrays

   Some constructors and other methods alternatively take an array of arrays as an argument. The array is treated as follows:

   1. ConstMFColor and MFColor

          float colors[][]

      colors[][] consists of an array of sets of three float-values (representing red, green and blue).

   2. ConstMFRotation and MFRotation

          float rotations[][]

      rotations[][] consists of an array of sets of four float-values (representing axisX, axisY, axisZ and angle).

   3. ConstMFVec2f and MFVec2f

          float vec2s[][]

      vec2s[][] consists of an array of sets of two float-values (representing x and y).

   4. ConstMFVec3f and MFVec3f

          float vec3s[][]

      vec3s[][] consists of an array of sets of three float-values (representing x, y and z).

#### B.6.3.2 Constructors and methods

The following describes how arrays are interpreted in detail for each constructor and method.

Suppose NA represents the number of elements in the array specified as an argument of some constructors and other methods, and NT represents the number of elements which the target object requires or has. For example, if the target object is SFColor, it requires exactly 3 float values.

In the following description, suppose SF* represents subclasses of Field class, ConstSF* represents subclasses of ConstField class, MF* represents subclasses of MField class and ConstMF* represents subclasses of ConstMField class.

1. A single-dimensional array

   In the following description, if the target object is:

   - ConstSFColor and SFColor, NT is exactly 3
   - ConstMFColor and MFColor, NT is a multiple of 3, and NA is rounded down to a multiple of 3
   - ConstSFRotation and SFRotation, NT is exactly 4
   - ConstMFRotation and MFRotation, NT is a multiple of 4, and NA is rounded down to a multiple of 4
   - ConstSFVec2f and SFVec2f, NT is exactly 2
   - ConstMFVec2f and MFVec2f, NT is a multiple of 2, and NA is rounded down to a multiple of 2
   - ConstSFVec3f and SFVec3f, NT is exactly 3
   - ConstMFVec3f and MFVec3f, NT is a multiple of 3, and NA is rounded down to a multiple of 3
   - ConstSFImage and SFImage, NT is exactly width*height*components (width, height and number of components in the image, see 5.5, SFImage)
   1. For ConstSF* objects and SF* objects
      For all constructors and methods which take a single-dimensional array as an argument, the following rules are applied.
      NA shall be larger than or equal to NT. If NA is larger than NT, the elements from the 0-th to the (NT - 1)-th element are used and remaining elements are ignored. Otherwise, an exception(ArrayIndexOutOfBoundsException) is thrown.

      For example, when the array is used as an argument of the setValue() for SFColor, the array shall contain at least 3 float values. If the array contains more than 3 float values, the first 3 values are used.

   2. For ConstMF* objects and MF* objects
      - For constructor.

        The same rule for ConstSF* and SF* objects is applied.

        For example, when the array is used as an argument of the constructor for MFColor, the array shall contain at least 3 float values. If the array contains 3N, 3N +1 or 3N + 2 float values, the first 3N values are used.

      - For setValue() method.

        If NT is smaller than or equal to NA, NT is increased to NA and then all elements of the array are copied into the target object. If NT is larger than NA, NT is decreased to NA and then all elements of the array are copied into the target object.

      - For getValue() method.

        If NT is smaller than or equal to NA, all elements of the target object are copied into the first NT elemets of the array. If NT is larger than NA, an exception (ArrayIndexOutOfBoundsException) is thrown.

      - For set1Value() method.

        The target element (the index-th element) is treated as an SF* object. So the same rule for ConstSF* and SF* objects is applied.

      - For get1Value() method.

        The target element (the index-th element) is treated as an SF* (or ConstSF*) object. So the same rule for ConstSF* and SF* objects is applied.

      - For addValue() and insertValue() method.

        The corresponding SF* object is created using the argument, and then added to the target object or inserted into the target object.

2. A single integer and a single-dimensional array

   For all constructors and methods which take a single integer value (called size) and a single-dimensional array as arguments, for example, MFFloat(int size, float values[]), the following rule is applied.

   The size parameter specifies the number of valid elements in the array from the 0-th element to the (size - 1)-th element; all other values are ignored. This means that the method may be passed an array of length size or larger.

   The valid elements are copied to a new array and the rules for a single-dimensional array are applied to the new array for all methods.

3. An array of arrays

   This argument is used only for MF* objects and ConstMF* objects. In the following case, suppose NA is the number of arrays (for example float f[4][3], NA is 4) specified as an argument of some constructors and other methods and NT is the return value of getSize() method of each object.

   - For constructor.
     The object which has NA elements is created.
   - For setValue() method.
     If NT is smaller than or equal to NA, NT is increased to NA and then all elements of the array are copied into the target object. If NT is larger than NA, NT is decreased to NA and then all elements of the array are copied into the target object.
   - For getValue() method.
     If NT is smaller than or equal to NA, all elements of the target object are copied into the array. If NT is larger than NA, an exception(ArrayIndexOutOfBoundsException) is thrown.

### B.6.4 Node class

The Node class has several methods:

1. `String getType()`
   is the method to return the type of the node.
2. `ConstField getEventOut(String eventOutName)`
   is the method to get the reference to the node's eventOut whose name is eventOutName. The return value can be converted to the appropriate subclass of the Field class, (see B.6.2, Field class and ConstField class).
3. `Field getEventIn(String eventInName)`
   is the method to get the reference to the node's eventIn whose name is eventInName. The return value can be converted to the appropriate subclass of the Field class, (see B.6.2, Field class and ConstField class). EventIn is a write-only field. When the getValue() method is invoked on a Field object obtained by the getEventIn() method, the return value is unspecified.
4. `Field getExposedField(String exposedFieldName)`
   is the method to get the reference to the node's exposedField whose name is exposedFieldName. The return value can be converted to the appropriate subclass of the Field class, (see B.6.2, Field class and ConstField class).
5. `Browser getBrowser()`
   is the method to get the browser object that this node is contained in (see B.6.5, Browser class).
6. `String toString()`
   is the same as the toString() method of SFNode (ConstSFNode).

When the setValue(), set1Value(), addValue(), insertValue(), delete() or clear() methods are invoked on a Field object obtained by the getExposedField() method, the call generates an eventOut in the VRML scene (see also B.6.2, Field class and ConstField class, and B.6.3, Array handling). The effect of this eventOut is specified by the associated Route(s) in the VRML scene. In the case of the set1Value(), addValue(), insertValue() or delete() methods, all elements of the VRML node's exposedField are retrieved, then the value specified as an argument is set, added, inserted or deleted (as appropriate) to/from the elements, then stored as the elements in the corresponding VRML node's exposedField, and then the eventOut is sent. In the case of the clear() method, all elements of VRML node's exposedField are cleared and an eventOut with zero elements is sent (see the definition of the clear() method).

When the setValue() or clear() methods are invoked on a Field object obtained by the getEventIn() method, the call generates an eventIn in the VRML scene. When the set1Value(), addValue(), insertValue() or delete() methods are invoked on the Field object, an exception (InvalidFieldChangeException) is thrown.

### B.6.5 Browser class

This section lists the public Java platform interfaces to the Browser class, which allows scripts to get and set browser information. For descriptions of the following methods, see 4.12.10, Browser script interface. Table B.1 lists the Browser class methods.

####
Table B.1 -- Browser class methods

Return value | Method name
`String` | `getName``()`
`String` | `getVersion``()`
`float` | `getCurrentSpeed``()`
`float` | `getCurrentFrameRate``()`
`String` | `getWorldURL``()`
`void` | `replaceWorld``(BaseNode[] nodes)`
`BaseNode[]` | `createVrmlFromString``(String vrmlSyntax)`
`void` | `createVrmlFromURL``(String[] url, BaseNode node, String event)`
`void` | `addRoute``(BaseNode fromNode, String fromEventOut,` `BaseNode toNode, String toEventIn)`
`void` | `deleteRoute``(BaseNode fromNode,` `String fromEventOut,` `BaseNode toNode, String toEventIn)`
`void` | `loadURL``(String[] url, String[] parameter)`
`void` | `setDescription``(String description)`

See B.9.2.1, vrml package, for each method's definition.

Table B.2 contains conversions from the types used in Browser class to Java platform types.

#### Table B.2 -- VRML and Java platform types

VRML type | Java platform type
--- | ---
SFString | String
SFFloat | float
MFString | String[]
MFNode | BaseNode[]

When a relative URL is specified as an argument of the loadURL() and createVrmlFromURL() method, the path is relative to the script file containing these methods (see 4.5.3, Relative URLs).

### B.6.6 User-defined classes and packages

The Java platform classes defined by a user can be used in the Java program. They are first searched from the directories specified in the CLASSPATH environment variable and then the directory where the Java program's class file is placed.

If the Java platform class is in a package, this package is searched from the directories specified in the CLASSPATH environment variable and then the directory where the Java program's class file is placed.

### B.6.7 Standard Java platform packages

Java programs have access to the full set of classes available in `java.*`. All parts of the Java platform are required to work as "normal" for the Java platform. So all methods specified in this annex are required to be thread-safe. The security model is browser specific.

## B.7 Exceptions

Java platform methods may throw the following exceptions:

1. InvalidFieldException
   is thrown at the time getField() is executed and the field name is invalid.
2. InvalidEventInException
   is thrown at the time getEventIn() is executed and the eventIn name is invalid.
3. InvalidEventOutException
   is thrown at the time getEventOut() is executed and the eventOut name is invalid.
4. InvalidExposedFieldException
   is thrown at the time getExposedField() is executed and the exposedField name is invalid.
5. InvalidVRMLSyntaxException
   is thrown at the time createVrmlFromString(), createVrmlFromURL() or loadURL() is executed and the vrml syntax is invalid.
6. InvalidRouteException
   is thrown at the time addRoute() or deleteRoute() is executed and one or more of the arguments is invalid.
7. InvalidFieldChangeException
   may be thrown as a result of all sorts of illegal field changes, for example:
   1. Adding a node from one World as the child of a node in another World.
   2. Creating a circularity in a scene graph.
   3. Setting an invalid string on enumerated fields, such as the fogType field of the Fog node.
   4. Calling the set1Value(), addValue() or delete() on a Field object obtained by the getEventIn() method.
8. ArrayIndexOutOfBoundsException
   is generated at the time getValue(), set1Value(), insertValue() or delete() is executed and the index is out of bound (see B.6.2, Field class and ConstField class). This is the standard exception defined in the Java platform Array class.
9. IllegalArgumentException
   is generated at the time loadURL() or createVrmlFromURL() is executed and an error is occurred before retrieving the content of the url (see B.6.5, Browser class). This is the standard exception defined by the Java platform.

If exceptions are not caught by authors, a browser's behaviour is unspecified (see B.10, Example of exception class).

## B.8 Examples

The following is an example of a Script node which determines whether a given color contains a lot of red. The Script node exposes a field, an eventIn, and an eventOut:

        Script {
          field    SFColor currentColor 0 0 0
          eventIn  SFColor colorIn
          eventOut SFBool  isRed
          url      "Example4.class"
        }

The following is the source code for the Example4.java file that gets called every time an eventIn is routed to the above Script node:

Example4.java:

    import vrml.*;
    import vrml.field.*;
    import vrml.node.*;

    public class Example4 extends Script {
        // Declare field(s)
        private SFColor currentColor;

        // Declare eventOut
        private SFBool isRed;

        // buffer for  SFColor.getValue().
        private float colorBuff[] = new float[3];

        public void initialize(){
           currentColor = (SFColor) getField("currentColor");
           isRed = (SFBool) getEventOut("isRed");
        }

        public void processEvent(Event e){
            // This method is called when a colorIn event is received
            currentColor.setValue((ConstSFColor)e.getValue());
        }

        public void eventsProcessed(){
            currentColor.getValue(colorBuff);
            if (colorBuff[0] >= 0.5) // if red is at or above 50%
                isRed.setValue(true);
        }
    }

Details on when the methods defined in Example4.java are called may be found in 4.10.3, Execution model.

#### Example5: createVrmlFromUrl()

        Script {
          url "Example5.class"
          field   MFString target_url "foo.wrl"
          eventIn MFNode   nodesLoaded
          eventIn SFBool   trigger_event
        }

    Example5.java:
      import vrml.*;
      import vrml.field.*;
      import vrml.node.*;

      public class Example5 extends Script {
          private MFString target_url; // field
          private Browser browser;

          public void initialize(){
              target_url = (MFString)getField("target_url");
              browser = this.getBrowser();
          }

          public void processEvent(Event e){
              if(e.getName().equals("trigger_event")){
                   // do something and then fetch values
                   String[] urls;
                   urls = new String[target_url.getSize()];
                   target_url.getValue(urls);
                   browser.createVrmlFromURL(urls, this, "nodesLoaded");
              }
              if(e.getName().equals("nodesLoaded")){
                  // do something
              }
          }
      }

#### Example6: addRoute()

        DEF TS TouchSensor {}
        Script {
          url     "Example6.class"
          field   SFNode fromNode USE TS
          eventIn SFBool clicked
          eventIn SFBool trigger_event
        }

Example6.java:

      import vrml.*;
      import vrml.field.*;
      import vrml.node.*;

      public class Example6 extends Script {

          private SFNode fromNode;
          private Browser browser;

          public void initialize(){
              fromNode = (SFNode) getField("fromNode");
              browser = this.getBrowser();
          }

          public void processEvent(Event e){
              if(e.getName().equals("trigger_event")){
                  // do something and then add routing
                  browser.addRoute(fromNode.getValue(), "isActive", this, "clicked");
              }
              if(e.getName().equals("clicked")){
                  // do something
              }
          }
      }

## B.9 Class definitions

### B.9.1 Class hierarchy

The classes are divided into three packages: vrml, vrml.field and vrml.node.

    java.lang.Object
         |
         +- vrml.Event
         +- vrml.Browser
         +- vrml.Field
         |       +- vrml.field.SFBool
         |       +- vrml.field.SFColor
         |       +- vrml.field.SFFloat
         |       +- vrml.field.SFImage
         |       +- vrml.field.SFInt32
         |       +- vrml.field.SFNode
         |       +- vrml.field.SFRotation
         |       +- vrml.field.SFString
         |       +- vrml.field.SFTime
         |       +- vrml.field.SFVec2f
         |       +- vrml.field.SFVec3f
         |       |
         |       +- vrml.MField
         |       |       +- vrml.field.MFColor
         |       |       +- vrml.field.MFFloat
         |       |       +- vrml.field.MFInt32
         |       |       +- vrml.field.MFNode
         |       |       +- vrml.field.MFRotation
         |       |       +- vrml.field.MFString
         |       |       +- vrml.field.MFTime
         |       |       +- vrml.field.MFVec2f
         |       |       +- vrml.field.MFVec3f
         |       |
         |       +- vrml.ConstField
         |               +- vrml.field.ConstSFBool
         |               +- vrml.field.ConstSFColor
         |               +- vrml.field.ConstSFFloat
         |               +- vrml.field.ConstSFImage
         |               +- vrml.field.ConstSFInt32
         |               +- vrml.field.ConstSFNode
         |               +- vrml.field.ConstSFRotation
         |               +- vrml.field.ConstSFString
         |               +- vrml.field.ConstSFTime
         |               +- vrml.field.ConstSFVec2f
         |               +- vrml.field.ConstSFVec3f
         |               |
         |               +- vrml.ConstMField
         |                       +- vrml.field.ConstMFColor
         |                       +- vrml.field.ConstMFFloat
         |                       +- vrml.field.ConstMFInt32
         |                       +- vrml.field.ConstMFNode
         |                       +- vrml.field.ConstMFRotation
         |                       +- vrml.field.ConstMFString
         |                       +- vrml.field.ConstMFTime
         |                       +- vrml.field.ConstMFVec2f
         |                       +- vrml.field.ConstMFVec3f
         |
         +- vrml.BaseNode
                 +- vrml.node.Node
                 +- vrml.node.Script

    java.lang.Exception
         |
         +- java.lang.RuntimeException
         |       +- java.lang.IllegalArgumentException
         |               +- vrml.InvalidEventInException
         |               +- vrml.InvalidEventOutException
         |               +- vrml.InvalidExposedFieldException
         |               +- vrml.InvalidFieldChangeException
         |               +- vrml.InvalidFieldException
         |               +- vrml.InvalidRouteException
         |
         +- vrml.InvalidVRMLSyntaxException

### B.9.2 VRML packages

#### B.9.2.1 vrml package

    package vrml;

    public class Event implements Cloneable
    {
       public String getName();
       public double getTimeStamp();
       public ConstField getValue();
       public Object clone();

       public String toString();   // This overrides a method in Object
    }

    public class Browser
    {
       private Browser();
       public String toString();   // This overrides a method in Object

       // Browser interface
       public String getName();
       public String getVersion();

       public float getCurrentSpeed();

       public float getCurrentFrameRate();

       public String getWorldURL();
       public void replaceWorld(BaseNode[] nodes);

       public BaseNode[] createVrmlFromString(String vrmlSyntax)
         throws InvalidVRMLSyntaxException;

       public void createVrmlFromURL(String[] url, BaseNode node, String event)
         throws InvalidVRMLSyntaxException;

       public void addRoute(BaseNode fromNode, String fromEventOut,
                            BaseNode toNode, String toEventIn);

       public void deleteRoute(BaseNode fromNode, String fromEventOut,
                               BaseNode toNode, String toEventIn);

       public void loadURL(String[] url, String[] parameter)
         throws InvalidVRMLSyntaxException;

       public void setDescription(String description);
    }

    public abstract class Field implements Cloneable
    {
       public Object clone();
    }

    public abstract class MField extends Field
    {
       public abstract int getSize();
       public abstract void clear();
       public abstract void delete(int index);
    }

    public abstract class ConstField extends Field
    {
    }

    public abstract class ConstMField extends ConstField
    {
       public abstract int getSize();
    }

    //
    // This is the general BaseNode class
    //
    public abstract class BaseNode
    {
       // Returns the type of the node.  If the node is a prototype
       // it returns the name of the prototype.
       public String getType();

       // Get the Browser that this node is contained in.
       public Browser getBrowser();
    }

#### B.9.2.2 vrml.field package

    package vrml.field;

    public class SFBool extends Field
    {
       public SFBool();
       public SFBool(boolean value);

       public boolean getValue();

       public void setValue(boolean b);
       public void setValue(ConstSFBool b);
       public void setValue(SFBool b);

       public String toString();   // This overrides a method in Object
    }

    public class SFColor extends Field
    {
       public SFColor();
       public SFColor(float red, float green, float blue);

       public void getValue(float colors[]);
       public float getRed();
       public float getGreen();
       public float getBlue();

       public void setValue(float colors[]);
       public void setValue(float red, float green, float blue);
       public void setValue(ConstSFColor color);
       public void setValue(SFColor color);

       public String toString();   // This overrides a method in Object
    }

    public class SFFloat extends Field
    {
       public SFFloat();
       public SFFloat(float f);

       public float getValue();

       public void setValue(float f);
       public void setValue(ConstSFFloat f);
       public void setValue(SFFloat f);

       public String toString();   // This overrides a method in Object
    }

    public class SFImage extends Field
    {
       public SFImage();
       public SFImage(int width, int height, int components, byte pixels[]);

       public int getWidth();
       public int getHeight();
       public int getComponents();
       public void getPixels(byte pixels[]);

       public void setValue(int width, int height, int components,
                            byte pixels[]);
       public void setValue(ConstSFImage image);
       public void setValue(SFImage image);

       public String toString();   // This overrides a method in Object
    }

    public class SFInt32 extends Field
    {
       public SFInt32();
       public SFInt32(int value);

       public int getValue();

       public void setValue(int i);
       public void setValue(ConstSFInt32 i);
       public void setValue(SFInt32 i);

       public String toString();   // This overrides a method in Object
    }

    public class SFNode extends Field
    {
       public SFNode();
       public SFNode(BaseNode node);

       public BaseNode getValue();

       public void setValue(BaseNode node);
       public void setValue(ConstSFNode node);
       public void setValue(SFNode node);

       public String toString();   // This overrides a method in Object
    }

    public class SFRotation extends Field
    {
       public SFRotation();
       public SFRotation(float axisX, float axisY, float axisZ, float angle);

       public void getValue(float rotations[]);

       public void setValue(float rotations[]);
       public void setValue(float axisX, float axisY, float axisZ,
                            float angle);
       public void setValue(ConstSFRotation rotation);
       public void setValue(SFRotation rotation);

       public String toString();   // This overrides a method in Object
    }

    public class SFString extends Field
    {
       public SFString();
       public SFString(String s);

       public String getValue();

       public void setValue(String s);
       public void setValue(ConstSFString s);
       public void setValue(SFString s);

       public String toString();   // This overrides a method in Object
    }

    public class SFTime extends Field
    {
       public SFTime();
       public SFTime(double time);

       public double getValue();

       public void setValue(double time);
       public void setValue(ConstSFTime time);
       public void setValue(SFTime time);

       public String toString();   // This overrides a method in Object
    }

    public class SFVec2f extends Field
    {
       public SFVec2f();
       public SFVec2f(float x, float y);

       public void getValue(float vec2s[]);
       public float getX();
       public float getY();

       public void setValue(float vec2s[]);
       public void setValue(float x, float y);
       public void setValue(ConstSFVec2f vec);
       public void setValue(SFVec2f vec);

       public String toString();   // This overrides a method in Object
    }

    public class SFVec3f extends Field
    {
       public SFVec3f();
       public SFVec3f(float x, float y, float z);

       public void getValue(float vec3s[]);
       public float getX();
       public float getY();
       public float getZ();

       public void setValue(float vec3s[]);
       public void setValue(float x, float y, float z);
       public void setValue(ConstSFVec3f vec);
       public void setValue(SFVec3f vec);

       public String toString();   // This overrides a method in Object
    }

    public class MFColor extends MField
    {
       public MFColor();
       public MFColor(float colors[][]);
       public MFColor(float colors[]);
       public MFColor(int size, float colors[]);

       public void getValue(float colors[][]);
       public void getValue(float colors[]);

       public void get1Value(int index, float colors[]);
       public void get1Value(int index, SFColor color);

       public void setValue(float colors[][]);
       public void setValue(float colors[]);
       public void setValue(int size, float colors[]);
       /****************************************************
        color[0] ... color[size - 1] are used as color data
        in the way that color[0], color[1], and color[2]
        represent the first color. The number of colors
        is defined as "size / 3".
        ***************************************************/
       public void setValue(MFColor colors);
       public void setValue(ConstMFColor colors);

       public void set1Value(int index, ConstSFColor color);
       public void set1Value(int index, SFColor color);
       public void set1Value(int index, float red, float green, float blue);

       public void addValue(ConstSFColor color);
       public void addValue(SFColor color);
       public void addValue(float red, float green, float blue);

       public void insertValue(int index, ConstSFColor color);
       public void insertValue(int index, SFColor color);
       public void insertValue(int index, float red, float green, float blue);

       public String toString();   // This overrides a method in Object
    }

    public class MFFloat extends MField
    {
       public MFFloat();
       public MFFloat(int size, float values[]);
       public MFFloat(float values[]);

       public void getValue(float values[]);

       public float get1Value(int index);

       public void setValue(float values[]);
       public void setValue(int size, float values[]);
       public void setValue(MFFloat value);
       public void setValue(ConstMFFloat value);

       public void set1Value(int index, float f);
       public void set1Value(int index, ConstSFFloat f);
       public void set1Value(int index, SFFloat f);

       public void addValue(float f);
       public void addValue(ConstSFFloat f);
       public void addValue(SFFloat f);

       public void insertValue(int index, float f);
       public void insertValue(int index, ConstSFFloat f);
       public void insertValue(int index, SFFloat f);

       public String toString();   // This overrides a method in Object
    }

    public class MFInt32 extends MField
    {
       public MFInt32();
       public MFInt32(int size, int values[]);
       public MFInt32(int values[]);

       public void getValue(int values[]);

       public int get1Value(int index);

       public void setValue(int values[]);
       public void setValue(int size, int values[]);
       public void setValue(MFInt32 value);
       public void setValue(ConstMFInt32 value);

       public void set1Value(int index, int i);
       public void set1Value(int index, ConstSFInt32 i);
       public void set1Value(int index, SFInt32 i);

       public void addValue(int i);
       public void addValue(ConstSFInt32 i);
       public void addValue(SFInt32 i);

       public void insertValue(int index, int i);
       public void insertValue(int index, ConstSFInt32 i);
       public void insertValue(int index, SFInt32 i);

       public String toString();   // This overrides a method in Object
    }

    public class MFNode extends MField
    {
       public MFNode();
       public MFNode(int size, BaseNode node[]);
       public MFNode(BaseNode node[]);

       public void getValue(BaseNode node[]);

       public BaseNode get1Value(int index);

       public void setValue(BaseNode node[]);
       public void setValue(int size, BaseNode node[]);
       public void setValue(MFNode node);
       public void setValue(ConstMFNode node);

       public void set1Value(int index, BaseNode node);
       public void set1Value(int index, ConstSFNode node);
       public void set1Value(int index, SFNode node);

       public void addValue(BaseNode node);
       public void addValue(ConstSFNode node);
       public void addValue(SFNode node);

       public void insertValue(int index, BaseNode node);
       public void insertValue(int index, ConstSFNode node);
       public void insertValue(int index, SFNode node);

       public String toString();   // This overrides a method in Object
    }

    public class MFRotation extends MField
    {
       public MFRotation();
       public MFRotation(float rotations[][]);
       public MFRotation(float rotations[]);
       public MFRotation(int size, float rotations[]);

       public void getValue(float rotations[][]);
       public void getValue(float rotations[]);

       public void get1Value(int index, float rotations[]);
       public void get1Value(int index, SFRotation rotation);

       public void setValue(float rotations[][]);
       public void setValue(float rotations[]);
       public void setValue(int size, float rotations[]);
       public void setValue(MFRotation rotations);
       public void setValue(ConstMFRotation rotations);

       public void set1Value(int index, ConstSFRotation rotation);
       public void set1Value(int index, SFRotation rotation);
       public void set1Value(int index, float axisX, float axisY, float axisZ, float angle);

       public void addValue(ConstSFRotation rotation);
       public void addValue(SFRotation rotation);
       public void addValue(float axisX, float axisY, float axisZ, float angle);

       public void insertValue(int index, ConstSFRotation rotation);
       public void insertValue(int index, SFRotation rotation);
       public void insertValue(int index, float axisX, float axisY, float axisZ, float angle);

       public String toString();   // This overrides a method in Object
    }

    public class MFString extends MField
    {
       public MFString();
       public MFString(int size, String s[]);
       public MFString(String s[]);

       public void getValue(String s[]);

       public String get1Value(int index);

       public void setValue(String s[]);
       public void setValue(int size, String s[]);
       public void setValue(MFString s);
       public void setValue(ConstMFString s);

       public void set1Value(int index, String s);
       public void set1Value(int index, ConstSFString s);
       public void set1Value(int index, SFString s);

       public void addValue(String s);
       public void addValue(ConstSFString s);
       public void addValue(SFString s);

       public void insertValue(int index, String s);
       public void insertValue(int index, ConstSFString s);
       public void insertValue(int index, SFString s);

       public String toString();   // This overrides a method in Object
    }

    public class MFTime extends MField
    {
       public MFTime();
       public MFTime(int size, double times[]);
       public MFTime(double times[]);

       public void getValue(double times[]);

       public double get1Value(int index);

       public void setValue(double times[]);
       public void setValue(int size, double times[]);
       public void setValue(MFTime times);
       public void setValue(ConstMFTime times);

       public void set1Value(int index, double time);
       public void set1Value(int index, ConstSFTime time);
       public void set1Value(int index, SFTime time);

       public void addValue(double time);
       public void addValue(ConstSFTime time);
       public void addValue(SFTime time);

       public void insertValue(int index, double time);
       public void insertValue(int index, ConstSFTime time);
       public void insertValue(int index, SFTime time);

       public String toString();   // This overrides a method in Object
    }

    public class MFVec2f extends MField
    {
       public MFVec2f();
       public MFVec2f(float vec2s[][]);
       public MFVec2f(float vec2s[]);
       public MFVec2f(int size, float vec2s[]);

       public void getValue(float vec2s[][]);
       public void getValue(float vec2s[]);

       public void get1Value(int index, float vec2s[]);
       public void get1Value(int index, SFVec2f vec);

       public void setValue(float vec2s[][]);
       public void setValue(float vec2s[]);
       public void setValue(int size, float vec2s[]);
       public void setValue(MFVec2f vecs);
       public void setValue(ConstMFVec2f vecs);

       public void set1Value(int index, float x, float y);
       public void set1Value(int index, ConstSFVec2f vec);
       public void set1Value(int index, SFVec2f vec);

       public void addValue(float x, float y);
       public void addValue(ConstSFVec2f vec);
       public void addValue(SFVec2f vec);

       public void insertValue(int index, float x, float y);
       public void insertValue(int index, ConstSFVec2f vec);
       public void insertValue(int index, SFVec2f vec);

       public String toString();   // This overrides a method in Object
    }

    public class MFVec3f extends MField
    {
       public MFVec3f();
       public MFVec3f(float vec3s[][]);
       public MFVec3f(float vec3s[]);
       public MFVec3f(int size, float vec3s[]);

       public void getValue(float vec3s[][]);
       public void getValue(float vec3s[]);

       public void get1Value(int index, float vec3s[]);
       public void get1Value(int index, SFVec3f vec);

       public void setValue(float vec3s[][]);
       public void setValue(float vec3s[]);
       public void setValue(int size, float vec3s[]);
       public void setValue(MFVec3f vecs);
       public void setValue(ConstMFVec3f vecs);

       public void set1Value(int index, float x, float y, float z);
       public void set1Value(int index, ConstSFVec3f vec);
       public void set1Value(int index, SFVec3f vec);

       public void addValue(float x, float y, float z);
       public void addValue(ConstSFVec3f vec);
       public void addValue(SFVec3f vec);

       public void insertValue(int index, float x, float y, float z);
       public void insertValue(int index, ConstSFVec3f vec);
       public void insertValue(int index, SFVec3f vec);

       public String toString();   // This overrides a method in Object
    }

    public class ConstSFBool extends ConstField
    {
       public ConstSFBool(boolean value);

       public boolean getValue();

       public String toString();   // This overrides a method in Object
    }

    public class ConstSFColor extends ConstField
    {
       public ConstSFColor(float red, float green, float blue);

       public void getValue(float colors[]);
       public float getRed();
       public float getGreen();
       public float getBlue();

       public String toString();   // This overrides a method in Object
    }

    public class ConstSFFloat extends ConstField
    {
       public ConstSFFloat(float value);

       public float getValue();

       public String toString();   // This overrides a method in Object
    }

    public class ConstSFImage extends ConstField
    {
       public ConstSFImage(int width, int height, int components, byte pixels[]);

       public int getWidth();
       public int getHeight();
       public int getComponents();
       public void getPixels(byte pixels[]);

       public String toString();   // This overrides a method in Object
    }

    public class ConstSFInt32 extends ConstField
    {
       public ConstSFInt32(int value);

       public int getValue();

       public String toString();   // This overrides a method in Object
    }

    public class ConstSFNode extends ConstField
    {
       public ConstSFNode(BaseNode node);

       public BaseNode getValue();

       public String toString();   // This overrides a method in Object
    }

    public class ConstSFRotation extends ConstField
    {
       public ConstSFRotation(float axisX, float axisY, float axisZ, float angle);

       public void getValue(float rotations[]);

       public String toString();   // This overrides a method in Object
    }

    public class ConstSFString extends ConstField
    {
       public ConstSFString(String value);

       public String getValue();

       public String toString();   // This overrides a method in Object
    }

    public class ConstSFTime extends ConstField
    {
       public ConstSFTime(double time);

       public double getValue();

       public String toString();   // This overrides a method in Object
    }

    public class ConstSFVec2f extends ConstField
    {
       public ConstSFVec2f(float x, float y);

       public void getValue(float vec2s[]);
       public float getX();
       public float getY();

       public String toString();   // This overrides a method in Object
    }

    public class ConstSFVec3f extends ConstField
    {
       public ConstSFVec3f(float x, float y, float z);

       public void getValue(float vec3s[]);
       public float getX();
       public float getY();
       public float getZ();

       public String toString();   // This overrides a method in Object
    }

    public class ConstMFColor extends ConstMField
    {
       public ConstMFColor(float colors[][]);
       public ConstMFColor(float colors[]);
       public ConstMFColor(int size, float colors[]);

       public void getValue(float colors[][]);
       public void getValue(float colors[]);

       public void get1Value(int index, float colors[]);
       public void get1Value(int index, SFColor color);

       public String toString();   // This overrides a method in Object
    }

    public class ConstMFFloat extends ConstMField
    {
       public ConstMFFloat(int size, float values[]);
       public ConstMFFloat(float values[]);

       public void getValue(float values[]);

       public float get1Value(int index);

       public String toString();   // This overrides a method in Object
    }

    public class ConstMFInt32 extends ConstMField
    {
       public ConstMFInt32(int size, int values[]);
       public ConstMFInt32(int values[]);

       public void getValue(int values[]);

       public int get1Value(int index);

       public String toString();   // This overrides a method in Object
    }

    public class ConstMFNode extends ConstMField
    {
       public ConstMFNode(int size, BaseNode node[]);
       public ConstMFNode(BaseNode node[]);

       public void getValue(BaseNode node[]);

       public BaseNode get1Value(int index);

       public String toString();   // This overrides a method in Object
    }

    public class ConstMFRotation extends ConstMField
    {
       public ConstMFRotation(float rotations[][]);
       public ConstMFRotation(float rotations[]);
       public ConstMFRotation(int size, float rotations[]);

       public void getValue(float rotations[][]);
       public void getValue(float rotations[]);

       public void get1Value(int index, float rotations[]);
       public void get1Value(int index, SFRotation rotation);

       public String toString();   // This overrides a method in Object
    }

    public class ConstMFString extends ConstMField
    {
       public ConstMFString(int size, String s[]);
       public ConstMFString(String s[]);

       public void getValue(String values[]);

       public String get1Value(int index);

       public String toString();   // This overrides a method in Object
    }

    public class ConstMFTime extends ConstMField
    {
       public ConstMFTime(int size, double times[]);
       public ConstMFTime(double times[]);

       public void getValue(double times[]);

       public double get1Value(int index);

       public String toString();   // This overrides a method in Object
    }

    public class ConstMFVec2f extends ConstMField
    {
       public ConstMFVec2f(float vec2s[][]);
       public ConstMFVec2f(float vec2s[]);
       public ConstMFVec2f(int size, float vec2s[]);

       public void getValue(float vec2s[][]);
       public void getValue(float vec2s[]);

       public void get1Value(int index, float vec2s[]);
       public void get1Value(int index, SFVec2f vec);

       public String toString();   // This overrides a method in Object
    }

    public class ConstMFVec3f extends ConstMField
    {
       public ConstMFVec3f(float vec3s[][]);
       public ConstMFVec3f(float vec3s[]);
       public ConstMFVec3f(int size, float vec3s[]);

       public void getValue(float vec3s[][]);
       public void getValue(float vec3s[]);

       public void get1Value(int index, float vec3s[]);
       public void get1Value(int index, SFVec3f vec);

       public String toString();   // This overrides a method in Object
    }

#### B.9.2.3 vrml.node package

    package vrml.node;

    //
    // This is the general Node class
    //
    public abstract class Node extends BaseNode
    {
       // Get an EventIn by name. Return value is write-only.
       //   Throws an InvalidEventInException if eventInName isn't a valid
       //   eventIn name for a node of this type.
       public final Field getEventIn(String eventInName);

       // Get an EventOut by name. Return value is read-only.
       //   Throws an InvalidEventOutException if eventOutName isn't a valid
       //   eventOut name for a node of this type.
       public final ConstField getEventOut(String eventOutName);

       // Get an exposed field by name.
       //   Throws an InvalidExposedFieldException if exposedFieldName isn't a valid
       //   exposedField name for a node of this type.
       public final Field getExposedField(String exposedFieldName);

       public String toString();   // This overrides a method in Object
    }

    //
    // This is the general Script class, to be subclassed by all scripts.
    // Note that the provided methods allow the script author to explicitly
    // throw tailored exceptions in case something goes wrong in the
    // script.
    //
    public abstract class Script extends BaseNode
    {
       // This method is called before any event is generated
       public void initialize();

       // Get a Field by name.
       //   Throws an InvalidFieldException if fieldName isn't a valid
       //   field name for a node of this type.
       protected final Field getField(String fieldName);

       // Get an EventOut by name.
       //   Throws an InvalidEventOutException if eventOutName isn't a valid
       //   eventOut name for a node of this type.
       protected final Field getEventOut(String eventOutName);

       // Get an EventIn by name.
       //   Throws an InvalidEventInException if eventInName isn't a valid
       //   eventIn name for a node of this type.
       protected final Field getEventIn(String eventInName);

       // processEvents() is called automatically when the script receives
       //   some set of events. It shall not be called directly except by its subclass.
       //   count indicates the number of events delivered.
       public void processEvents(int count, Event events[]);

       // processEvent() is called automatically when the script receives
       // an event.
       public void processEvent(Event event);

       // eventsProcessed() is called after every invocation of processEvents().
       public void eventsProcessed()

       // shutdown() is called when this Script node is deleted.
       public void shutdown();

       public String toString();   // This overrides a method in Object
    }

## B.10 Example of exception class

public class InvalidEventInException extends IllegalArgumentException

    {
       /**
        * Constructs an InvalidEventInException with no detail message.
        */
       public InvalidEventInException(){
          super();
       }
       /**
        * Constructs an InvalidEventInException with the specified detail message.
        * A detail message is a String that describes this particular exception.
        * @param s the detail message
        */
       public InvalidEventInException(String s){
          super(s);
       }
    }

    public class InvalidEventOutException extends IllegalArgumentException
    {
       public InvalidEventOutException(){
          super();
       }
       public InvalidEventOutException(String s){
          super(s);
       }
    }

    public class InvalidExposedFieldException extends IllegalArgumentException
    {
       public InvalidExposedFieldException(){
          super();
       }
       public InvalidExposedFieldException(String s){
          super(s);
       }
    }

    public class InvalidFieldChangeException extends IllegalArgumentException
    {
       public InvalidFieldChangeException(){
          super();
       }
       public InvalidFieldChangeException(String s){
          super(s);
       }
    }

    public class InvalidFieldException extends IllegalArgumentException
    {
       public InvalidFieldException(){
          super();
       }
       public InvalidFieldException(String s){
          super(s);
       }
    }

    public class InvalidRouteException extends IllegalArgumentException
    {
       public InvalidRouteException(){
          super();
       }
       public InvalidRouteException(String s){
          super(s);
       }
    }

    public class InvalidVRMLSyntaxException extends Exception
    {
       public InvalidVRMLSyntaxException(){
          super();
       }
       public InvalidVRMLSyntaxException(String s){
          super(s);
       }

       public String getMessage();  // This overrides a method in Exception
    }

Questions or comments.
Copyright © 1997 The VRML Consortium Incorporated.
`http://www.vrml.org/Specifications/VRML97/part1/java.html`