com.twitter.heron.streamlet.impl.BuilderImpl 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;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Set;
import com.twitter.heron.api.topology.TopologyBuilder;
import com.twitter.heron.streamlet.Builder;
import com.twitter.heron.streamlet.SerializableSupplier;
import com.twitter.heron.streamlet.Source;
import com.twitter.heron.streamlet.Streamlet;
/**
* BuilderImpl implements the Builder interface.
* The builder keeps track of the all the sources of the
* computation dag and builds the Topology by traversing all
* the computation nodes.
*/
public final class BuilderImpl implements Builder {
private List> sources;
public BuilderImpl() {
sources = new LinkedList<>();
}
@Override
public Streamlet newSource(SerializableSupplier supplier) {
StreamletImpl retval = StreamletImpl.createSupplierStreamlet(supplier);
retval.setNumPartitions(1);
sources.add(retval);
return retval;
}
@Override
public Streamlet newSource(Source generator) {
StreamletImpl retval = StreamletImpl.createGeneratorStreamlet(generator);
retval.setNumPartitions(1);
sources.add(retval);
return retval;
}
/**
* We start traversing from all sources and build each node.
* @return TopologyBuilder class that represents the built topology
*/
public TopologyBuilder build() {
TopologyBuilder builder = new TopologyBuilder();
Set stageNames = new HashSet<>();
for (StreamletImpl streamlet : sources) {
streamlet.build(builder, stageNames);
}
for (StreamletImpl streamlet : sources) {
if (!streamlet.allBuilt()) {
throw new RuntimeException("Topology cannot be fully built! Are all sources added?");
}
}
return builder;
}
}