| /* |
| * 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.tinkerpop.gremlin.process.computer.traversal.step.map; |
| |
| import org.apache.tinkerpop.gremlin.process.computer.GraphFilter; |
| import org.apache.tinkerpop.gremlin.process.computer.Memory; |
| import org.apache.tinkerpop.gremlin.process.computer.ranking.pagerank.PageRankVertexProgram; |
| import org.apache.tinkerpop.gremlin.process.computer.traversal.lambda.HaltedTraversersCountTraversal; |
| import org.apache.tinkerpop.gremlin.process.traversal.Traversal; |
| import org.apache.tinkerpop.gremlin.process.traversal.TraversalStrategies; |
| import org.apache.tinkerpop.gremlin.process.traversal.dsl.graph.__; |
| import org.apache.tinkerpop.gremlin.process.traversal.step.ByModulating; |
| import org.apache.tinkerpop.gremlin.process.traversal.step.TimesModulating; |
| import org.apache.tinkerpop.gremlin.process.traversal.step.TraversalParent; |
| import org.apache.tinkerpop.gremlin.process.traversal.traverser.TraverserRequirement; |
| import org.apache.tinkerpop.gremlin.process.traversal.util.PureTraversal; |
| import org.apache.tinkerpop.gremlin.structure.Edge; |
| import org.apache.tinkerpop.gremlin.structure.Graph; |
| import org.apache.tinkerpop.gremlin.structure.Vertex; |
| import org.apache.tinkerpop.gremlin.structure.util.StringFactory; |
| |
| import java.util.Collections; |
| import java.util.List; |
| import java.util.Set; |
| |
| /** |
| * @author Marko A. Rodriguez (http://markorodriguez.com) |
| */ |
| public final class PageRankVertexProgramStep extends VertexProgramStep implements TraversalParent, ByModulating, TimesModulating { |
| |
| private PureTraversal<Vertex, Edge> edgeTraversal; |
| private String pageRankProperty = PageRankVertexProgram.PAGE_RANK; |
| private int times = 20; |
| private final double alpha; |
| |
| public PageRankVertexProgramStep(final Traversal.Admin traversal, final double alpha) { |
| super(traversal); |
| this.alpha = alpha; |
| this.modulateBy(__.<Vertex>outE().asAdmin()); |
| } |
| |
| @Override |
| public void modulateBy(final Traversal.Admin<?, ?> edgeTraversal) { |
| this.edgeTraversal = new PureTraversal<>((Traversal.Admin<Vertex, Edge>) edgeTraversal); |
| this.integrateChild(this.edgeTraversal.get()); |
| } |
| |
| @Override |
| public void modulateBy(final String pageRankProperty) { |
| this.pageRankProperty = pageRankProperty; |
| } |
| |
| @Override |
| public void modulateTimes(int times) { |
| this.times = times; |
| } |
| |
| @Override |
| public List<Traversal.Admin<Vertex, Edge>> getLocalChildren() { |
| return Collections.singletonList(this.edgeTraversal.get()); |
| } |
| |
| @Override |
| public String toString() { |
| return StringFactory.stepString(this, this.edgeTraversal.get(), this.pageRankProperty, this.times, new GraphFilter(this.computer)); |
| } |
| |
| @Override |
| public PageRankVertexProgram generateProgram(final Graph graph, final Memory memory) { |
| final Traversal.Admin<Vertex, Edge> detachedTraversal = this.edgeTraversal.getPure(); |
| detachedTraversal.setStrategies(TraversalStrategies.GlobalCache.getStrategies(graph.getClass())); |
| final PageRankVertexProgram.Builder builder = PageRankVertexProgram.build() |
| .property(this.pageRankProperty) |
| .iterations(this.times + 1) |
| .alpha(this.alpha) |
| .edges(detachedTraversal); |
| if (this.previousTraversalVertexProgram()) |
| builder.initialRank(new HaltedTraversersCountTraversal()); |
| return builder.create(graph); |
| } |
| |
| @Override |
| public Set<TraverserRequirement> getRequirements() { |
| return TraversalParent.super.getSelfAndChildRequirements(); |
| } |
| |
| @Override |
| public PageRankVertexProgramStep clone() { |
| final PageRankVertexProgramStep clone = (PageRankVertexProgramStep) super.clone(); |
| clone.edgeTraversal = this.edgeTraversal.clone(); |
| return clone; |
| } |
| |
| @Override |
| public void setTraversal(final Traversal.Admin<?, ?> parentTraversal) { |
| super.setTraversal(parentTraversal); |
| this.integrateChild(this.edgeTraversal.get()); |
| } |
| |
| @Override |
| public int hashCode() { |
| return super.hashCode() ^ this.edgeTraversal.hashCode() ^ this.pageRankProperty.hashCode() ^ this.times; |
| } |
| } |