Class SingletonListIterator
- java.lang.Object
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- org.apache.commons.collections.iterators.SingletonListIterator
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- All Implemented Interfaces:
java.util.Iterator
,java.util.ListIterator
,ResettableIterator
,ResettableListIterator
public class SingletonListIterator extends java.lang.Object implements java.util.ListIterator, ResettableListIterator
SingletonIterator
is anListIterator
over a single object instance.- Since:
- Commons Collections 2.1
- Version:
- $Revision: 646777 $ $Date: 2008-04-10 14:33:15 +0200 (Thu, 10 Apr 2008) $
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Field Summary
Fields Modifier and Type Field Description private boolean
beforeFirst
private boolean
nextCalled
private java.lang.Object
object
private boolean
removed
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Constructor Summary
Constructors Constructor Description SingletonListIterator(java.lang.Object object)
Constructs a newSingletonListIterator
.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description void
add(java.lang.Object obj)
Add always throwsUnsupportedOperationException
.boolean
hasNext()
Is another object available from the iterator?boolean
hasPrevious()
Is a previous object available from the iterator?java.lang.Object
next()
Get the next object from the iterator.int
nextIndex()
Returns the index of the element that would be returned by a subsequent call to next.java.lang.Object
previous()
Get the previous object from the iterator.int
previousIndex()
Returns the index of the element that would be returned by a subsequent call to previous.void
remove()
Remove the object from this iterator.void
reset()
Reset the iterator back to the start.void
set(java.lang.Object obj)
Set sets the value of the singleton.
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Method Detail
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hasNext
public boolean hasNext()
Is another object available from the iterator?This returns true if the single object hasn't been returned yet.
- Specified by:
hasNext
in interfacejava.util.Iterator
- Specified by:
hasNext
in interfacejava.util.ListIterator
- Returns:
- true if the single object hasn't been returned yet
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hasPrevious
public boolean hasPrevious()
Is a previous object available from the iterator?This returns true if the single object has been returned.
- Specified by:
hasPrevious
in interfacejava.util.ListIterator
- Returns:
- true if the single object has been returned
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nextIndex
public int nextIndex()
Returns the index of the element that would be returned by a subsequent call to next.- Specified by:
nextIndex
in interfacejava.util.ListIterator
- Returns:
- 0 or 1 depending on current state.
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previousIndex
public int previousIndex()
Returns the index of the element that would be returned by a subsequent call to previous. A return value of -1 indicates that the iterator is currently at the start.- Specified by:
previousIndex
in interfacejava.util.ListIterator
- Returns:
- 0 or -1 depending on current state.
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next
public java.lang.Object next()
Get the next object from the iterator.This returns the single object if it hasn't been returned yet.
- Specified by:
next
in interfacejava.util.Iterator
- Specified by:
next
in interfacejava.util.ListIterator
- Returns:
- the single object
- Throws:
java.util.NoSuchElementException
- if the single object has already been returned
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previous
public java.lang.Object previous()
Get the previous object from the iterator.This returns the single object if it has been returned.
- Specified by:
previous
in interfacejava.util.ListIterator
- Returns:
- the single object
- Throws:
java.util.NoSuchElementException
- if the single object has not already been returned
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remove
public void remove()
Remove the object from this iterator.- Specified by:
remove
in interfacejava.util.Iterator
- Specified by:
remove
in interfacejava.util.ListIterator
- Throws:
java.lang.IllegalStateException
- if the next or previous method has not yet been called, or the remove method has already been called after the last call to next or previous.
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add
public void add(java.lang.Object obj)
Add always throwsUnsupportedOperationException
.- Specified by:
add
in interfacejava.util.ListIterator
- Throws:
java.lang.UnsupportedOperationException
- always
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set
public void set(java.lang.Object obj)
Set sets the value of the singleton.- Specified by:
set
in interfacejava.util.ListIterator
- Parameters:
obj
- the object to set- Throws:
java.lang.IllegalStateException
- if next has not been called or the object has been removed
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reset
public void reset()
Reset the iterator back to the start.- Specified by:
reset
in interfaceResettableIterator
- Specified by:
reset
in interfaceResettableListIterator
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