Package ptolemy.data

Class ObjectToken

  • Direct Known Subclasses:
    ConceptToken, ImageToken

    public class ObjectToken
    extends Token
    A token that contains a reference to an arbitrary object. Note that when this token constructed, the object passed to the constructor is not cloned. Thus, care must be exercised to ensure that actors do not modify that object in a nondeterministic way, unless such nondeterminism is acceptable.
    Since:
    Ptolemy II 0.2
    Version:
    $Id$
    Author:
    Edward A. Lee
    Pt.AcceptedRating:
    Yellow (wbwu)
    Pt.ProposedRating:
    Yellow (yuhong)
    • Field Detail

      • NULL

        public static final ObjectToken NULL
        A new empty ObjectToken.
      • _class

        protected java.lang.Class _class
        The class of the object.
      • _value

        protected java.lang.Object _value
        The actual Object. This is protected to allow access in derived classes only.
    • Constructor Detail

      • ObjectToken

        public ObjectToken()
        Construct an empty token.
      • ObjectToken

        public ObjectToken​(java.lang.Object value)
                    throws IllegalActionException
        Construct a token with a reference to the specified object.
        Parameters:
        value - The specified object referred to by this token.
        Throws:
        IllegalActionException - If the argument is not of the appropriate type (may be thrown by derived classes, but is not thrown here).
      • ObjectToken

        public ObjectToken​(java.lang.Object value,
                           java.lang.Class<?> valueClass)
                    throws IllegalActionException
        Construct a token with the given value and the given class as the value's type.
        Parameters:
        value - The value.
        valueClass - The class of the value.
        Throws:
        IllegalActionException - If the argument is not of the appropriate type.
    • Method Detail

      • convert

        public static ObjectToken convert​(Token token)
                                   throws IllegalActionException
        Convert the specified token into an instance of ObjectToken. This method does lossless conversion. If the argument is already an instance of ObjectToken, it is returned without any change. Otherwise, if the argument is below ObjectToken in the type hierarchy, it is converted to an instance of ObjectToken or one of the subclasses of ObjectToken and returned. If none of the above condition is met, an exception is thrown.
        Parameters:
        token - The token to be converted to an ObjectToken.
        Returns:
        An ObjectToken.
        Throws:
        IllegalActionException - If the conversion cannot be carried out.
      • equals

        public boolean equals​(java.lang.Object object)
        Return true if the argument is an instance of ObjectToken and its contained object is equal to the object contained in this token, as tested by the equals() method of the contained object.
        Overrides:
        equals in class java.lang.Object
        Parameters:
        object - An instance of Object.
        Returns:
        True if the argument is an instance of ObjectToken and its contained object is equal to the object contained in this token.
      • getType

        public Type getType()
        Return the type of this token.
        Overrides:
        getType in class Token
        Returns:
        BaseType.OBJECT
      • getValue

        public java.lang.Object getValue()
        Return the value of the token, a reference to an object.
        Returns:
        The Object in this token.
      • getValueClass

        public java.lang.Class getValueClass()
        Return the class of the object contained in this token.
        Returns:
        The class of the object.
      • hashCode

        public int hashCode()
        Return a hash code value for this token. This method returns the hash code of the contained object.
        Overrides:
        hashCode in class java.lang.Object
        Returns:
        A hash code value for this token.
      • isCloseTo

        public final BooleanToken isCloseTo​(Token token,
                                            double epsilon)
                                     throws IllegalActionException
        Test that the value of this token is close to the first argument, where "close" means that the distance between them is less than or equal to the second argument. This method only makes sense for tokens where the distance between them is reasonably represented as a double. If the argument token is not of the same type as this token, then either this token or the argument will be converted, if possible, to the type of the other.

        Subclasses should not generally override this method, but override the protected _isCloseTo() method to ensure that type conversion is performed consistently.

        Overrides:
        isCloseTo in class Token
        Parameters:
        token - The token to test closeness of this token with.
        epsilon - The value that we use to determine whether two tokens are close. Ignored in this class.
        Returns:
        A boolean token that contains the value true if the value and units of this token are close to those of the argument token.
        Throws:
        IllegalActionException - If the argument token and this token are of incomparable types, or the operation does not make sense for the given types.
      • isEqualTo

        public BooleanToken isEqualTo​(Token rightArgument)
        Compare this ObjectToken to the given argument, and return true if the values contained in the two are the same Java object.
        Overrides:
        isEqualTo in class Token
        Parameters:
        rightArgument - The argument.
        Returns:
        true if the values are the same Java object, or false otherwise.
      • object

        public static ObjectToken object​(java.lang.String className)
                                  throws IllegalActionException
        Return an ObjectToken with value null and class specified by the className argument.
        Parameters:
        className - The className.
        Returns:
        The ObjectToken.
        Throws:
        IllegalActionException - If the class with className as its name cannot be loaded.
      • toString

        public java.lang.String toString()
        Return the value of this token as a string. The returned syntax looks like a function call to a one argument method named "object". The argument is the string representation of the contained object, or the string "null" if the object is null. Notice that this syntax is not currently parsable by the expression language.
        Overrides:
        toString in class Token
        Returns:
        A String representing the object.
      • _isCloseTo

        protected BooleanToken _isCloseTo​(Token rightArgument,
                                          double epsilon)
                                   throws IllegalActionException
        Test for closeness of the values of this Token and the argument Token. It is assumed that the type of the argument is an ObjectToken.
        Parameters:
        rightArgument - The token to add to this token.
        epsilon - The value that we use to determine whether two tokens are close. This parameter is ignored by this class.
        Returns:
        A BooleanToken containing the result.
        Throws:
        IllegalActionException - If this method is not supported by the derived class.
      • _isEqualTo

        protected BooleanToken _isEqualTo​(Token rightArgument)
                                   throws IllegalActionException
        Test for equality of the values of this Token and the argument Token. It is assumed that the type of the argument is ObjectToken.
        Parameters:
        rightArgument - The token to add to this token.
        Returns:
        A BooleanToken containing the result.
        Throws:
        IllegalActionException - If this method is not supported by the derived class.