net.yacy.cora.util

Class LookAheadIterator<A>

java.lang.Object

net.yacy.cora.util.LookAheadIterator<A>

All Implemented Interfaces:

java.lang.Iterable<A>, java.util.Iterator<A>

Direct Known Subclasses:

ArrayStack.BlobLengths, ArrayStack.BlobValues, ChunkIterator, DHTSelection.acceptRemoteIndexSeedEnum, DHTSelection.providesRemoteCrawlURLsEnum, HeapReader.entries, MapHeap.FullMapIterator, ReferenceIterator, Tables.HeapRowIterator, Tables.OrderedRowIterator, WebStructureGraph.StructureIterator

public abstract class LookAheadIterator<A>
extends java.lang.Object
implements java.util.Iterator<A>, java.lang.Iterable<A>

convenience class for iterator implementations that naturally terminate when the next() method would return null. This is usually implemented using a next0() method and a wrapper for next() and hasNext() that evaluates the latest return value of next0() To use this class just implement the next0() method

Field Summary

Fields

Modifier and Type	Field and Description
private boolean	fresh
private A	next

Constructor Summary

Constructors

Constructor and Description
LookAheadIterator()

Method Summary

Methods

Modifier and Type	Method and Description
private void	checkInit()
boolean	hasNext()
java.util.Iterator<A>	iterator()
A	next()
protected abstract A	next0() the internal next-method
void	remove() a remove is not possible with this implementation

Methods inherited from class java.lang.Object

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

Field Detail

fresh

private boolean fresh

next

private A next

Constructor Detail

LookAheadIterator

public LookAheadIterator()

Method Detail

iterator

public final java.util.Iterator<A> iterator()

Specified by:

iterator in interface java.lang.Iterable<A>

next0

protected abstract A next0()

the internal next-method

Returns:

a value of type A if available or null if no more value are available

checkInit

private final void checkInit()

hasNext

public final boolean hasNext()

Specified by:

hasNext in interface java.util.Iterator<A>

next

public final A next()

Specified by:

next in interface java.util.Iterator<A>

remove

public final void remove()

a remove is not possible with this implementation

Specified by:

remove in interface java.util.Iterator<A>