org.apache.cassandra.utils
Class MergeIterator<In,Out>

java.lang.Object
  com.google.common.collect.UnmodifiableIterator<T>
      com.google.common.collect.AbstractIterator<Out>
          org.apache.cassandra.utils.MergeIterator<In,Out>

All Implemented Interfaces:

java.io.Closeable, java.util.Iterator<Out>, CloseableIterator<Out>

public abstract class MergeIterator<In,Out>
extends com.google.common.collect.AbstractIterator<Out>
implements CloseableIterator<Out>

Merges sorted input iterators which individually contain unique items.

Nested Class Summary

protected static class	MergeIterator.Candidate<In>
static class	MergeIterator.Reducer<In,Out> Accumulator that collects values of type A, and outputs a value of type B.

Field Summary

java.util.Comparator<In>	comp
protected java.util.List<? extends CloseableIterator<In>>	iterators
protected java.util.PriorityQueue<MergeIterator.Candidate<In>>	queue

Constructor Summary

protected

MergeIterator(java.util.List<? extends CloseableIterator<In>> iters, java.util.Comparator<In> comp)

Method Summary

protected abstract void	advance() Returns consumed items to the queue.
void	close()
protected Out	computeNext()
protected abstract Out	consume() Consumes sorted items from the queue: should only remove items from the queue, not add them.
static <E> MergeIterator<E,E>	get(java.util.List<? extends CloseableIterator<E>> iters)
static <E> MergeIterator<E,E>	get(java.util.List<? extends CloseableIterator<E>> iters, java.util.Comparator<E> comp)
static <In,Out> MergeIterator<In,Out>	get(java.util.List<? extends CloseableIterator<In>> iters, java.util.Comparator<In> comp, MergeIterator.Reducer<In,Out> reducer)
java.lang.Iterable<? extends CloseableIterator<In>>	iterators()

Methods inherited from class com.google.common.collect.AbstractIterator

endOfData, hasNext, next, peek

Methods inherited from class com.google.common.collect.UnmodifiableIterator

remove

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Iterator

hasNext, next, remove

Field Detail

comp

public final java.util.Comparator<In> comp

iterators

protected final java.util.List<? extends CloseableIterator<In>> iterators

queue

protected final java.util.PriorityQueue<MergeIterator.Candidate<In>> queue

Constructor Detail

MergeIterator

protected MergeIterator(java.util.List<? extends CloseableIterator<In>> iters,
                        java.util.Comparator<In> comp)

Method Detail

get

public static <E> MergeIterator<E,E> get(java.util.List<? extends CloseableIterator<E>> iters)

get

public static <E> MergeIterator<E,E> get(java.util.List<? extends CloseableIterator<E>> iters,
                                         java.util.Comparator<E> comp)

get

public static <In,Out> MergeIterator<In,Out> get(java.util.List<? extends CloseableIterator<In>> iters,
                                                 java.util.Comparator<In> comp,
                                                 MergeIterator.Reducer<In,Out> reducer)

iterators

public java.lang.Iterable<? extends CloseableIterator<In>> iterators()

consume

protected abstract Out consume()

Consumes sorted items from the queue: should only remove items from the queue, not add them.

advance

protected abstract void advance()

Returns consumed items to the queue.

computeNext

protected final Out computeNext()

Specified by:

computeNext in class com.google.common.collect.AbstractIterator<Out>

close

public void close()

Specified by:

close in interface java.io.Closeable