Package com.openinventor.inventor.fields

Class SoField

  • Direct Known Subclasses:
    SoMField, SoSField
    public abstract class SoField
extends Inventor
    Base class for all fields. SoField is the abstract base class for all fields. Fields are the data elements contained within nodes and are the input values for engines. Each node or engine class specifies a set of fields and associates a name with each. These names define the semantics of the field (e.g., the SoCube node contains three float fields named width, height, and depth). Field classes provide the access methods that indirectly allow editing and querying of data within nodes.

    There are two abstract subclasses of SoField: SoSField is the base class for all single-valued field classes and SoMField is the base class for all multiple-valued fields, which contain dynamic arrays of values. Subclasses of SoSField have an SoSF prefix, and subclasses of SoMField have an SoMF prefix. See the reference pages for SoSField and SoMField for additional methods.

    Fields are typically constructed only within node or engine instances; if you need a field that is not part of a node or engine, you can create a GlobalField ; see the methods on SoDB for creating global fields.

    Fields can be connected either directly to another field, or can be connected to the output of an engine. The value of a field with a connection will change when the thing it is connected to changes. For example, consider a field "A" that is connected from "B" (by A->connectFrom(B) ). When B's value is changed, A's value will also change. Note that A and B may have different values, even if they are connected: if A's value is set after B's value, A's value will be different from B's until B's value is set.

    A field can be connected to several other fields, but can be connected from only one source.

    It is possible (and often useful) to create loops of field connections (for example, A connected from B and B connected from A). If there are loops, then the rule is that the last setValue() done overrides any connections in to that value. You can think of setting the value of a field as immediately propagating that value forward into all the fields it is connected to, with the propagation stopping at the place where the original setValue() occurred if there is a connection loop. (Actually, a more efficient mechanism than this is used, but the semantics are the same.)

    If you try to connect two fields of differing types, Open Inventor will automatically try to insert a field converter engine between them to convert values from one type into the other. Open Inventor has most reasonable conversions built-in (multiple-valued field to single-valued and vice versa, anything to SoSFString, anything to SoSFTrigger, float/short/unsigned short/int32_t/uint32_t/etc numeric conversions, etc). You can add field converters using SoDB's extender method addConverter(); see the SoDB.h header file for details. You can also find out if a converter is available with the SoDB.getConverter() method.

    Fields each define their own file format for reading and being written to files, but all fields follow the same conventions:

    Fields in a node or engine are written as the name of the field followed by the field's value; fields are not written if they have not been modified since they were created (if they have their default value).

    The ignored flag is written as a "~" character after the field's value (if the field's value is its default value, just the "~" is written).

    Field connections are written as an "=" followed by the container of the field or engine output that the field is connected to, followed by a "." and the name of the field or engine output. For example: 

       DEF node1 Transform translation 1 1 1
   DEF node2 Scale scaleFactor 1 1 1 = USE node1.translation
    Global fields are written as part of an internal SoFieldContainer class called GlobalField , which writes out an SoSFName field named type whose value is the type of the global field, followed by a field of that type whose name is the name of the global field. For example, a global uint32_t field called "FrameCounter" whose value is 494 would be written as: 

       GlobalField{
   type SoSFUInt32
   FrameCounter 494
   }

    See Also:
    SoSField, SoMField, SoNode, SoDB

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      boolean appendConnection​(SoEngineOutput engineOutput)
      Appends this field to the list of connections from another engineOutput.
      boolean appendConnection​(SoField field)
      Appends this field to the list of connections from another field.
      boolean connectFrom​(SoEngineOutput engineOutput)
      Connects this field from an engine output.
      boolean connectFrom​(SoField field)
      Connects this field to another field.
      void disconnect()
      Disconnect the field from whatever it was connected to.
      void disconnect​(SoEngineOutput engineOutput)
      Disconnect the field from the requested engineOutput.
      void disconnect​(SoField field)
      Disconnect the field from the requested field.
      void enableConnection​(boolean flag)
      Field connections may be enabled and disabled.
      boolean equals​(java.lang.Object obj)  
      java.lang.String get()
      Returns the value of the field in the Open Inventor file format, even if the field has its default value.
      SoEngineOutput getConnectedEngine()
      Returns true if this field is being written into by an engine, and returns the engine output it is connected to in engineOutput.
      SoField getConnectedField()
      Returns true if this field is being written into by another field, and returns the field it is connected to in writingField.
      SoFieldContainer getContainer()
      Returns the object that contains this field.
      int getNumConnections()
      Returns the number of connections to this field.
      long getValueSize()
      Gets the size of the value.
      boolean isConnected()
      Returns true if the field is connected to anything.
      boolean isConnectedFromEngine()
      Returns true if the field is connected to an engine's output.
      boolean isConnectedFromField()
      Returns true if the field is connected to another field.
      boolean isConnectedFromVRMLInterp()
      Returns true if the field is connected to a VRML interpOutput.
      boolean isConnectionEnabled()
      Returns false if connections to this field are disabled.
      boolean isDefault()
      Gets the state of default flag of the field.
      boolean isIgnored()
      Gets the ignore flag for this field.
      boolean set​(java.lang.String valueString)
      Sets the field to the given value, which is an ASCII string in the Open Inventor file format.
      void setIgnored​(boolean ig)
      Sets the ignore flag for this field.
      void touch()
      Simulates a change to the field, causing attached sensors to fire, connected fields and engines to be marked as needing evaluation, and so forth.

      • Methods inherited from class java.lang.Object

        getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Method Detail

      • connectFrom

        public boolean connectFrom​(SoField field)
        Connects this field to another field. If the field was connected to something before, it will be automatically disconnected (a field may have only one connection writing into it at a time). Unless connections to the field are disabled (see enableConnection()), the field's value will be set to the value of the thing it is connected to.

      • set

        public boolean set​(java.lang.String valueString)
        Sets the field to the given value, which is an ASCII string in the Open Inventor file format. Each field subclass defines its own file format; see their reference pages for information on their file format. The string should contain only the field's value, not the field's name (e.g., "1.0", not "width 1.0"). This method returns true if the string is valid, false if it is not.

      • getConnectedEngine

        public SoEngineOutput getConnectedEngine()
        Returns true if this field is being written into by an engine, and returns the engine output it is connected to in engineOutput. Returns false and does not modify engineOutput if it is not connected to an engine.

      • getContainer

        public SoFieldContainer getContainer()
        Returns the object that contains this field. The type of the object will be either SoNode, SoEngine, or will be a global field container (note that the global field container class is internal to Open Inventor; see the methods for creating and accessing global fields on SoDB).

      • connectFrom

        public boolean connectFrom​(SoEngineOutput engineOutput)
        Connects this field from an engine output. If the field was connected to something before, it will be automatically disconnected (a field may have only one connection writing into it at a time). Unless connections to the field are disabled (see enableConnection()), the field's value will be set to the value of the thing it is connected to.

      • isIgnored

        public boolean isIgnored()
        Gets the ignore flag for this field.

      • setIgnored

        public void setIgnored​(boolean ig)
        Sets the ignore flag for this field. When a field's ignore flag is set to true, the field is not used during traversal for rendering and other actions. This flag enables you to ignore certain fields in a node and to use others. For example, to ignore the specular color in a material node so the value is inherited from the previous material. Some fields are not inherited and are thus not affected by the Ignore flag.

        Examples of fields that are not inherited are the fields of shape nodes, light-source nodes, some groups, and cameras, as well as the fields in the SoEnvironment node. If you set the Ignore flag for a field whose values are not inherited, Open Inventor simply uses the field's default values.

        The default value for this flag is false.

      • getConnectedField

        public SoField getConnectedField()
        Returns true if this field is being written into by another field, and returns the field it is connected to in writingField. Returns false and does not modify writingField if it is not connected to a field.

      • isConnectionEnabled

        public boolean isConnectionEnabled()
        Returns false if connections to this field are disabled. Note that this may return false even if the field is not connected to anything.

      • enableConnection

        public void enableConnection​(boolean flag)
        Field connections may be enabled and disabled. Disabling a field's connection is almost exactly like disconnecting it; the only difference is that you can later re-enable the connection by calling enableConnection()( true ). Note that disconnecting an engine output can cause the engine's reference count to be decremented and the engine to be deleted, but disabling the connection does not decrement its reference count.

        Re-enabling a connection will cause the value of the field to be changed to the engine output or field to which it is connected.

        A field's connection-enabled status is maintained even if the field is disconnected or reconnected. By default, connections are enabled.

      • isDefault

        public boolean isDefault()
        Gets the state of default flag of the field. This flag will be true for any field whose value is not modified after construction and will be false for those that have changed (each node or engine determines what the default values for its fields are). Note: the state of this flag should not be set explicitly from within applications.

      • isConnectedFromField

        public boolean isConnectedFromField()
        Returns true if the field is connected to another field.

      • getNumConnections

        public int getNumConnections()
        Returns the number of connections to this field.

      • equals

        public boolean equals​(java.lang.Object obj)
        Overrides:
        equals in class java.lang.Object

      • disconnect

        public void disconnect()
        Disconnect the field from whatever it was connected to. This does nothing if the field was not connected.

      • disconnect

        public void disconnect​(SoField field)
        Disconnect the field from the requested field. All other connections remain.

      • appendConnection

        public boolean appendConnection​(SoEngineOutput engineOutput)
        Appends this field to the list of connections from another engineOutput. Previous connections remain unchanged. Unless connections to the field are disabled, the field value will be set to that of the engineOutput that was last touched.

      • appendConnection

        public boolean appendConnection​(SoField field)
        Appends this field to the list of connections from another field. Previous connections remain unchanged. Unless connections to the field are disabled, the field value will be set to that of the field that was last touched.

      • disconnect

        public void disconnect​(SoEngineOutput engineOutput)
        Disconnect the field from the requested engineOutput. All other connections remain.

      • get

        public java.lang.String get()
        Returns the value of the field in the Open Inventor file format, even if the field has its default value.

      • isConnectedFromEngine

        public boolean isConnectedFromEngine()
        Returns true if the field is connected to an engine's output.

      • isConnectedFromVRMLInterp

        public boolean isConnectedFromVRMLInterp()
        Returns true if the field is connected to a VRML interpOutput.

      • touch

        public void touch()
        Simulates a change to the field, causing attached sensors to fire, connected fields and engines to be marked as needing evaluation, and so forth. Calling touch() on an instance of a derived field class is equivalent to calling setValue(getValue()) using the derived class's methods, except that the field's isDefault() status remains unchanged.

      • isConnected

        public boolean isConnected()
        Returns true if the field is connected to anything.

      • getValueSize

        public long getValueSize()
        Gets the size of the value.