org.apache.flink.runtime.operators.sort.AbstractMergeInnerJoinIterator Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.flink.runtime.operators.sort;
import org.apache.flink.api.common.functions.FlatJoinFunction;
import org.apache.flink.api.common.typeutils.TypeComparator;
import org.apache.flink.api.common.typeutils.TypePairComparator;
import org.apache.flink.api.common.typeutils.TypeSerializer;
import org.apache.flink.runtime.io.disk.iomanager.IOManager;
import org.apache.flink.runtime.jobgraph.tasks.AbstractInvokable;
import org.apache.flink.runtime.memory.MemoryAllocationException;
import org.apache.flink.runtime.memory.MemoryManager;
import org.apache.flink.util.Collector;
import org.apache.flink.util.MutableObjectIterator;
import java.util.Iterator;
/**
* An implementation of the {@link org.apache.flink.runtime.operators.util.JoinTaskIterator} that realizes the
* joining through a sort-merge join strategy.
*/
public abstract class AbstractMergeInnerJoinIterator extends AbstractMergeIterator {
public AbstractMergeInnerJoinIterator(
MutableObjectIterator input1, MutableObjectIterator input2,
TypeSerializer serializer1, TypeComparator comparator1,
TypeSerializer serializer2, TypeComparator comparator2,
TypePairComparator pairComparator,
MemoryManager memoryManager,
IOManager ioManager,
int numMemoryPages,
AbstractInvokable parentTask)
throws MemoryAllocationException {
super(input1, input2, serializer1, comparator1, serializer2, comparator2, pairComparator, memoryManager, ioManager, numMemoryPages, parentTask);
}
/**
* Calls the JoinFunction#join() method for all two key-value pairs that share the same key and come
* from different inputs. The output of the join() method is forwarded.
*
* This method first zig-zags between the two sorted inputs in order to find a common
* key, and then calls the join stub with the cross product of the values.
*
* @throws Exception Forwards all exceptions from the user code and the I/O system.
* @see org.apache.flink.runtime.operators.util.JoinTaskIterator#callWithNextKey(org.apache.flink.api.common.functions.FlatJoinFunction, org.apache.flink.util.Collector)
*/
@Override
public boolean callWithNextKey(final FlatJoinFunction joinFunction, final Collector collector)
throws Exception {
if (!this.iterator1.nextKey() || !this.iterator2.nextKey()) {
// consume all remaining keys (hack to prevent remaining inputs during iterations, lets get rid of this soon)
while (this.iterator1.nextKey()) {
}
while (this.iterator2.nextKey()) {
}
return false;
}
final TypePairComparator comparator = this.pairComparator;
comparator.setReference(this.iterator1.getCurrent());
T2 current2 = this.iterator2.getCurrent();
// zig zag
while (true) {
// determine the relation between the (possibly composite) keys
final int comp = comparator.compareToReference(current2);
if (comp == 0) {
break;
}
if (comp < 0) {
if (!this.iterator2.nextKey()) {
return false;
}
current2 = this.iterator2.getCurrent();
} else {
if (!this.iterator1.nextKey()) {
return false;
}
comparator.setReference(this.iterator1.getCurrent());
}
}
// here, we have a common key! call the join function with the cross product of the
// values
final Iterator values1 = this.iterator1.getValues();
final Iterator values2 = this.iterator2.getValues();
crossMatchingGroup(values1, values2, joinFunction, collector);
return true;
}
}