com.twitter.heron.streamlet.impl.streamlets.UnionStreamlet Maven / Gradle / Ivy
// Copyright 2017 Twitter. All rights reserved.
//
// 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 com.twitter.heron.streamlet.impl.streamlets;
import java.util.Set;
import com.twitter.heron.api.topology.TopologyBuilder;
import com.twitter.heron.streamlet.impl.StreamletImpl;
import com.twitter.heron.streamlet.impl.operators.UnionOperator;
/**
* UnionStreamlet is a Streamlet composed of all the elements of two
* parent streamlets.
*/
public class UnionStreamlet extends StreamletImpl {
private StreamletImpl left;
private StreamletImpl right;
public UnionStreamlet(StreamletImpl left, StreamletImpl right) {
this.left = left;
this.right = right;
setNumPartitions(left.getNumPartitions());
}
@Override
public boolean doBuild(TopologyBuilder bldr, Set stageNames) {
if (!left.isBuilt() || !right.isBuilt()) {
// We can only continue to build us if both of our parents are built.
// The system will call us again later
return false;
}
setDefaultNameIfNone(StreamletNamePrefix.UNION, stageNames);
bldr.setBolt(getName(), new UnionOperator(),
getNumPartitions()).shuffleGrouping(left.getName()).shuffleGrouping(right.getName());
return true;
}
}