Class EmptyIterator<E>
java.lang.Object
org.apache.commons.collections4.iterators.EmptyIterator<E>
- Type Parameters:
- E- the type of elements returned by this iterator.
- All Implemented Interfaces:
- Iterator<E>,- ResettableIterator<E>
Provides an implementation of an empty iterator.
 
 This class provides an implementation of an empty iterator.
 This class provides for binary compatibility between Commons Collections
 2.1.1 and 3.1 due to issues with IteratorUtils.
 
- Since:
- 2.1.1 and 3.1
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Field SummaryFieldsModifier and TypeFieldDescriptionstatic final IteratorSingleton instance of the iterator.static final ResettableIteratorSingleton instance of the iterator.
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Constructor SummaryConstructors
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Method SummaryModifier and TypeMethodDescriptionvoidDeprecated.Will be removed in 5.0 without replacement.static <E> Iterator<E> Gets a typed empty iterator instance.booleanhasNext()Always returns false, this iterator contains no elements.booleanAlways returns false, this iterator contains no elements.next()Always throws IllegalStateException, this iterator contains no elements.intAlways returns 0, this iterator contains no elements.previous()Always throws IllegalStateException, this iterator contains no elements.intAlways returns -1, this iterator contains no elements.voidremove()Always throws IllegalStateException, this iterator contains no elements.voidreset()Resets the iterator back to the position at which the iterator was created.static <E> ResettableIterator<E> Gets a typed resettable empty iterator instance.voidAlways throws IllegalStateException, this iterator contains no elements.Methods inherited from class java.lang.Objectclone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, waitMethods inherited from interface java.util.IteratorforEachRemaining
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Field Details- 
RESETTABLE_INSTANCESingleton instance of the iterator.- Since:
- 3.1
 
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INSTANCE
 
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Constructor Details- 
EmptyIteratorprotected EmptyIterator()Constructs a new instance.
 
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Method Details- 
emptyIteratorGets a typed empty iterator instance.- Type Parameters:
- E- the element type
- Returns:
- Iterator<E>
 
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resettableEmptyIteratorGets a typed resettable empty iterator instance.- Type Parameters:
- E- the element type
- Returns:
- ResettableIterator<E>
 
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addDeprecated.Will be removed in 5.0 without replacement.Always throws UnsupportedOperationException.- Parameters:
- ignored- ignore.
- Throws:
- UnsupportedOperationException- Always thrown.
 
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hasNext
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hasPreviouspublic boolean hasPrevious()Always returns false, this iterator contains no elements.- Returns:
- Always false.
 
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nextAlways throws IllegalStateException, this iterator contains no elements.- Specified by:
- nextin interface- Iterator<E>
- Returns:
- Always throws IllegalStateException.
- Throws:
- IllegalStateException- Always thrown.
 
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nextIndexpublic int nextIndex()Always returns 0, this iterator contains no elements.- Returns:
- Always returns 0.
 
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previousAlways throws IllegalStateException, this iterator contains no elements.- Returns:
- Always throws IllegalStateException.
- Throws:
- IllegalStateException- Always thrown.
 
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previousIndexpublic int previousIndex()Always returns -1, this iterator contains no elements.- Returns:
- Always returns -1.
 
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removepublic void remove()Always throws IllegalStateException, this iterator contains no elements.- Specified by:
- removein interface- Iterator<E>
- Throws:
- IllegalStateException- Always thrown.
 
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resetpublic void reset()Description copied from interface:ResettableIteratorResets the iterator back to the position at which the iterator was created.- Specified by:
- resetin interface- ResettableIterator<E>
 
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setAlways throws IllegalStateException, this iterator contains no elements.- Parameters:
- ignored- ignored.
- Throws:
- IllegalStateException- Always thrown.
 
 
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