Package org.apache.commons.configuration2

Class PrefixedKeysIterator

java.lang.Object

org.apache.commons.configuration2.PrefixedKeysIterator

All Implemented Interfaces:

Iterator<String>

final class PrefixedKeysIterator
extends Object
implements Iterator<String>

A specialized iterator implementation used by AbstractConfiguration to return an iteration over all keys starting with a specified prefix.

This class is basically a stripped-down version of the FilterIterator class of Commons Collections

Field Summary

Fields

Modifier and Type	Field	Description
private final String	delimiter	Stores the prefix delimiter.
private final Iterator<String>	iterator	Stores the wrapped iterator.
private String	nextElement	Stores the next element in the iteration.
private boolean	nextElementSet	A flag whether the next element has been calculated.
private final String	prefix	Stores the prefix.

Constructor Summary

Constructors

Constructor	Description
PrefixedKeysIterator(Iterator<String> wrappedIterator, String keyPrefix)	Creates a new instance of PrefixedKeysIterator and sets the wrapped iterator and the prefix for the accepted keys.
PrefixedKeysIterator(Iterator<String> wrappedIterator, String keyPrefix, String prefixDelimiter)	Creates a new instance of PrefixedKeysIterator and sets the wrapped iterator and the prefix as well as the delimiter for the preix for the accepted keys.

Method Summary

Modifier and Type	Method	Description
boolean	hasNext()	Tests whether there are more elements in the iteration.
String	next()	Returns the next element in the iteration.
void	remove()	Removes from the underlying collection of the base iterator the last element returned by this iterator.
private boolean	setNextElement()	Sets the next element in the iteration.
String	toString()

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Iterator

forEachRemaining

Field Details

iterator

private final Iterator<String> iterator

Stores the wrapped iterator.

prefix

private final String prefix

Stores the prefix.

delimiter

private final String delimiter

Stores the prefix delimiter. Default delimiter is "."

nextElement

private String nextElement

Stores the next element in the iteration.

nextElementSet

private boolean nextElementSet

A flag whether the next element has been calculated.

Constructor Details

PrefixedKeysIterator

public PrefixedKeysIterator(Iterator<String> wrappedIterator,
 String keyPrefix)

Creates a new instance of PrefixedKeysIterator and sets the wrapped iterator and the prefix for the accepted keys.

Parameters:

wrappedIterator - the wrapped iterator

keyPrefix - the prefix of the allowed keys

PrefixedKeysIterator

public PrefixedKeysIterator(Iterator<String> wrappedIterator,
 String keyPrefix,
 String prefixDelimiter)

Creates a new instance of PrefixedKeysIterator and sets the wrapped iterator and the prefix as well as the delimiter for the preix for the accepted keys.

Parameters:

wrappedIterator - the wrapped iterator

keyPrefix - the prefix of the allowed keys

prefixDelimiter - the prefix delimiter

Since:

2.10.0

Method Details

hasNext

public boolean hasNext()

Tests whether there are more elements in the iteration.

Specified by:

hasNext in interface Iterator<String>

Returns:

whether there are more elements in the iteration.

next

public String next()

Returns the next element in the iteration. This is the next key that matches the specified prefix.

Specified by:

next in interface Iterator<String>

Returns:

the next element in the iteration

Throws:

NoSuchElementException - if there is no next element

remove

public void remove()

Removes from the underlying collection of the base iterator the last element returned by this iterator. This method can only be called if next() was called, but not after hasNext(), because the hasNext() call changes the base iterator.

Specified by:

remove in interface Iterator<String>

Throws:

IllegalStateException - if hasNext() has already been called.

setNextElement

private boolean setNextElement()

Sets the next element in the iteration. The return value indicates whether such an element can be found.

Returns:

a flag whether a next element exists

toString

public String toString()

Overrides:

toString in class Object