| /* |
| * 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.nemo.common.ir.vertex.executionproperty; |
| |
| import org.apache.nemo.common.ir.executionproperty.VertexExecutionProperty; |
| |
| /** |
| * This property decides the number of parallel tasks to use for executing the corresponding IRVertex. |
| * |
| * Changing the parallelism requires also changing other execution properties that refer to task offsets. |
| * Such execution properties include: |
| * {@link ResourceSiteProperty} |
| * {@link ResourceAntiAffinityProperty} |
| * {@link org.apache.nemo.common.ir.edge.executionproperty.PartitionerProperty} |
| * {@link org.apache.nemo.common.ir.edge.executionproperty.PartitionSetProperty} |
| * |
| * Moreover, vertices with one-to-one relationships must have the same parallelism. |
| * {@link org.apache.nemo.common.ir.edge.executionproperty.CommunicationPatternProperty} |
| * |
| * Finally, the parallelism cannot be larger than the number of source (e.g., HDFS) input data partitions. |
| * {@link org.apache.nemo.common.ir.vertex.SourceVertex} |
| * |
| * A violation of any of the above criteria will be caught by Nemo, to ensure correct application semantics. |
| */ |
| public final class ParallelismProperty extends VertexExecutionProperty<Integer> { |
| /** |
| * Constructor. |
| * |
| * @param value value of the execution property. |
| */ |
| private ParallelismProperty(final Integer value) { |
| super(value); |
| } |
| |
| /** |
| * Static method exposing the constructor. |
| * |
| * @param value value of the new execution property. |
| * @return the newly created execution property. |
| */ |
| public static ParallelismProperty of(final Integer value) { |
| return new ParallelismProperty(value); |
| } |
| } |