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gnu.java.util

Class EmptyEnumeration<T>

Implemented Interfaces:
Enumeration<E>, Serializable
public final class EmptyEnumeration<T>
extends Object
implements Enumeration<E>, Serializable
This is a helper class that produces an empty Enumerations. There is only one instance of this class that can be used whenever one needs a non-null but empty enumeration. Using this class prevents multiple small objects and inner classes. getInstance() returns the only instance of this class. It can be shared by multiple objects and threads.
See Also:
Serialized Form

Method Summary

static EmptyEnumeration
getInstance()
Returns an instance of this class for Object.
boolean
hasMoreElements()
Returns false, since there are no elements.
T
nextElement()
Always throws NoSuchElementException, since it is empty.

Methods inherited from class java.lang.Object

clone, equals, extends Object> getClass, finalize, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

getInstance

public static EmptyEnumeration getInstance()
 Returns an instance of this class for Object.
 It can be shared by multiple objects and threads.

Returns:
the common empty enumeration
hasMoreElements
public boolean hasMoreElements()
 Returns false, since there are no elements.

Specified by:
hasMoreElements in interface Enumeration<E>
Returns:
false
nextElement
public T nextElement()
 Always throws NoSuchElementException, since it is empty.

Specified by:
nextElement in interface Enumeration<E>
Throws:
NoSuchElementException - this is empty
EmptyEnumeration.java -- a constant empty enumeration
   Copyright (C) 2001, 2002 Free Software Foundation, Inc.

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