org.apache.flink.runtime.operators.sort

Class MergeMatchIterator<T1,T2,O>

java.lang.Object

org.apache.flink.runtime.operators.sort.MergeMatchIterator<T1,T2,O>

All Implemented Interfaces:

JoinTaskIterator<T1,T2,O>

public class MergeMatchIterator<T1,T2,O>
extends Object
implements JoinTaskIterator<T1,T2,O>

An implementation of the JoinTaskIterator that realizes the matching through a sort-merge join strategy.

Constructor Summary

Constructors

Constructor and Description
MergeMatchIterator(MutableObjectIterator<T1> input1, MutableObjectIterator<T2> input2, TypeSerializer<T1> serializer1, TypeComparator<T1> comparator1, TypeSerializer<T2> serializer2, TypeComparator<T2> comparator2, TypePairComparator<T1,T2> pairComparator, MemoryManager memoryManager, IOManager ioManager, int numMemoryPages, AbstractInvokable parentTask)

Method Summary

Modifier and Type	Method and Description
void	abort() Aborts the matching process.
boolean	callWithNextKey(FlatJoinFunction<T1,T2,O> matchFunction, Collector<O> collector) Calls the JoinFunction#match() method for all two key-value pairs that share the same key and come from different inputs.
void	close() General-purpose close method.
void	open() General-purpose open method.

Methods inherited from class java.lang.Object

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

Constructor Detail

MergeMatchIterator

public MergeMatchIterator(MutableObjectIterator<T1> input1,
                          MutableObjectIterator<T2> input2,
                          TypeSerializer<T1> serializer1,
                          TypeComparator<T1> comparator1,
                          TypeSerializer<T2> serializer2,
                          TypeComparator<T2> comparator2,
                          TypePairComparator<T1,T2> pairComparator,
                          MemoryManager memoryManager,
                          IOManager ioManager,
                          int numMemoryPages,
                          AbstractInvokable parentTask)
                   throws MemoryAllocationException

Throws:

MemoryAllocationException

Method Detail

open

public void open()
          throws IOException

Description copied from interface: JoinTaskIterator

General-purpose open method. Initializes the internal strategy (for example triggers the sorting of the inputs or starts building hash tables).

Specified by:

open in interface JoinTaskIterator<T1,T2,O>

Throws:

IOException - Thrown, if an I/O error occurred while preparing the data. An example is a failing external sort.

close

public void close()

Description copied from interface: JoinTaskIterator

General-purpose close method. Works after the principle of best effort. The internal structures are released, but errors that occur on the way are not reported.

Specified by:

close in interface JoinTaskIterator<T1,T2,O>

abort

public void abort()

Description copied from interface: JoinTaskIterator

Aborts the matching process. This extra abort method is supplied, because a significant time may pass while calling the match stub with the cross product of all values that share the same key. A call to this abort method signals an interrupt to that procedure.

Specified by:

abort in interface JoinTaskIterator<T1,T2,O>

callWithNextKey

public boolean callWithNextKey(FlatJoinFunction<T1,T2,O> matchFunction,
                               Collector<O> collector)
                        throws Exception

Calls the JoinFunction#match() method for all two key-value pairs that share the same key and come from different inputs. The output of the match() method is forwarded.

This method first zig-zags between the two sorted inputs in order to find a common key, and then calls the match stub with the cross product of the values.

Specified by:

callWithNextKey in interface JoinTaskIterator<T1,T2,O>

Parameters:

matchFunction - The match stub containing the match function which is called with the keys.

collector - The collector to pass the match function.

Returns:

True, if a next key exists, false if no more keys exist.

Throws:

Exception - Forwards all exceptions from the user code and the I/O system.

See Also:

JoinTaskIterator.callWithNextKey(FlatJoinFunction, Collector)