/***********************************************************************************************************************
* Copyright (C) 2010-2013 by the Stratosphere project (http://stratosphere.eu)
*
* Licensed 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 eu.stratosphere.nephele.executiongraph;
import eu.stratosphere.nephele.jobgraph.DistributionPattern;
public final class DistributionPatternProvider {
/**
* Checks if two subtasks of different tasks should be wired.
*
* @param pattern
* the distribution pattern that should be used
* @param nodeLowerStage
* the index of the producing task's subtask
* @param nodeUpperStage
* the index of the consuming task's subtask
* @param sizeSetLowerStage
* the number of subtasks of the producing task
* @param sizeSetUpperStage
* the number of subtasks of the consuming task
* @return <code>true</code> if a wire between the two considered subtasks should be created, <code>false</code>
* otherwise
*/
public static boolean createWire(final DistributionPattern pattern, final int nodeLowerStage,
final int nodeUpperStage, final int sizeSetLowerStage, final int sizeSetUpperStage) {
switch (pattern) {
case BIPARTITE:
return true;
case POINTWISE:
if (sizeSetLowerStage < sizeSetUpperStage) {
if (nodeLowerStage == (nodeUpperStage % sizeSetLowerStage)) {
return true;
}
} else {
if ((nodeLowerStage % sizeSetUpperStage) == nodeUpperStage) {
return true;
}
}
return false;
/*
* case STAR:
* if (sizeSetLowerStage > sizeSetUpperStage) {
* int groupNumber = nodeLowerStage / Math.max(sizeSetLowerStage / sizeSetUpperStage, 1);
* if (nodeUpperStage == groupNumber) {
* return true;
* }
* } else {
* int groupNumber = nodeUpperStage / Math.max(sizeSetUpperStage / sizeSetLowerStage, 1);
* if (nodeLowerStage == groupNumber) {
* return true;
* }
* }
* return false;
*/
default:
// this will never happen.
throw new IllegalStateException("No Match for Distribution Pattern found.");
}
}
}