org.foray.ps
Class PsNull

java.lang.Object
  org.foray.ps.PsNull

All Implemented Interfaces:

PsObject, PsObjectSimple

public final class PsNull
extends Object
implements PsObjectSimple

A PostScript null object.

Method Summary

PsObject	duplicate() This is a shallow copy.
boolean	equals(Object anObject)
PsNull	getInstance() Returns the singleton instance of this class.
PsName	getTypeName() Needed for the "type" operator.
boolean	isComparable(PsObject object) Test the comparability of two PSObjects.
boolean	isComposite() The method should be overridden by composite objects.
boolean	isExecutable() Indicates whether this object is executable.

Methods inherited from class java.lang.Object

clone, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

getInstance

public PsNull getInstance()

Returns the singleton instance of this class.

Returns:

The singleton instance of this class.

duplicate

public PsObject duplicate()

Description copied from interface: PsObject

This is a shallow copy. Specifically, composite objects should generally return themselves. Simple objects should return copies of themselves.

Specified by:

duplicate in interface PsObject

Returns:

A duplicate of this that conforms to what is expected by the "dup" operator.

isComposite

public boolean isComposite()

Description copied from interface: PsObject

The method should be overridden by composite objects.

Specified by:

isComposite in interface PsObject

Returns:

True iff this object is a composite PostScript object.

equals

public boolean equals(Object anObject)

Overrides:

equals in class Object

isExecutable

public boolean isExecutable()

Description copied from interface: PsObject

Indicates whether this object is executable.

Specified by:

isExecutable in interface PsObject

Returns:

True iff this object is executable.

isComparable

public boolean isComparable(PsObject object)

Description copied from interface: PsObject

Test the comparability of two PSObjects. Used in the eq, ne, lt, etc. operators.

Specified by:

isComparable in interface PsObject

Parameters:

object - The object that should be tested for comparability.

Returns:

True if this is comparable to object, false otherwise.

getTypeName

public PsName getTypeName()

Description copied from interface: PsObject

Needed for the "type" operator.

Specified by:

getTypeName in interface PsObject

Returns:

The type name as defined in PSRM2, Chapter 8, "type" operator.