Java tutorial
/** * 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.storm.streams; import com.google.common.collect.ArrayListMultimap; import com.google.common.collect.Multimap; import com.google.common.collect.Multimaps; import org.apache.storm.generated.StreamInfo; import org.apache.storm.topology.IComponent; import org.apache.storm.topology.OutputFieldsGetter; import org.apache.storm.tuple.Fields; import java.io.Serializable; import java.util.Collection; import java.util.Collections; import java.util.HashSet; import java.util.Map; import java.util.Set; /** * Base class for a Node which form the vertices of the topology DAG. */ abstract class Node implements Serializable { private final Set<String> outputStreams; protected final Fields outputFields; protected GroupingInfo groupingInfo; protected String componentId; protected int parallelism; // the parent streams that this node subscribes to private final Multimap<Node, String> parentStreams = ArrayListMultimap.create(); private boolean windowed; private boolean emitsPair; Node(Set<String> outputStreams, Fields outputFields, String componentId, int parallelism, GroupingInfo groupingInfo) { this.outputStreams = new HashSet<>(outputStreams); this.outputFields = outputFields; this.componentId = componentId; this.parallelism = parallelism; this.groupingInfo = groupingInfo; } Node(String outputStream, Fields outputFields, String componentId, int parallelism, GroupingInfo groupingInfo) { this(Collections.singleton(outputStream), outputFields, componentId, parallelism, groupingInfo); } Node(String outputStream, Fields outputFields, String componentId, GroupingInfo groupingInfo) { this(outputStream, outputFields, componentId, 1, groupingInfo); } Node(String outputStream, Fields outputFields) { this(outputStream, outputFields, null); } Node(String outputStream, Fields outputFields, GroupingInfo groupingInfo) { this(outputStream, outputFields, null, groupingInfo); } GroupingInfo getGroupingInfo() { return groupingInfo; } void setGroupingInfo(GroupingInfo groupingInfo) { this.groupingInfo = groupingInfo; } public Fields getOutputFields() { return outputFields; } String getComponentId() { return componentId; } void setComponentId(String componentId) { this.componentId = componentId; } int getParallelism() { return parallelism; } void setParallelism(int parallelism) { this.parallelism = parallelism; } void addParentStream(Node parent, String streamId) { parentStreams.put(parent, streamId); } void removeParentStreams(Node parent) { parentStreams.removeAll(parent); } Set<String> getOutputStreams() { return Collections.unmodifiableSet(outputStreams); } public boolean isWindowed() { return windowed; } public void setWindowed(boolean windowed) { this.windowed = windowed; } Collection<String> getParentStreams(Node parent) { return parentStreams.get(parent); } Set<Node> getParents(String stream) { Multimap<String, Node> rev = Multimaps.invertFrom(parentStreams, ArrayListMultimap.<String, Node>create()); return new HashSet<>(rev.get(stream)); } Set<Node> getParents() { return parentStreams.keySet(); } void addOutputStream(String streamId) { outputStreams.add(streamId); } static Fields getOutputFields(IComponent component, String streamId) { OutputFieldsGetter getter = new OutputFieldsGetter(); component.declareOutputFields(getter); Map<String, StreamInfo> fieldsDeclaration = getter.getFieldsDeclaration(); if ((fieldsDeclaration != null) && fieldsDeclaration.containsKey(streamId)) { return new Fields(fieldsDeclaration.get(streamId).get_output_fields()); } return new Fields(); } public boolean emitsPair() { return emitsPair; } public void setEmitsPair(boolean emitsPair) { this.emitsPair = emitsPair; } @Override public String toString() { return "Node{" + "outputStreams=" + outputStreams + ", outputFields=" + outputFields + ", groupingInfo=" + groupingInfo + ", componentId='" + componentId + '\'' + ", parallelism=" + parallelism + ", parentStreams=" + parentStreams + ", windowed=" + windowed + ", emitsPair=" + emitsPair + '}'; } }