| /* |
| * 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.traversal.step.map; |
| |
| import org.apache.tinkerpop.gremlin.process.traversal.Traversal; |
| import org.apache.tinkerpop.gremlin.process.traversal.Traverser; |
| import org.apache.tinkerpop.gremlin.process.traversal.step.TraversalParent; |
| import org.apache.tinkerpop.gremlin.process.traversal.traverser.TraverserRequirement; |
| import org.apache.tinkerpop.gremlin.structure.util.StringFactory; |
| import org.apache.tinkerpop.gremlin.util.iterator.EmptyIterator; |
| |
| import java.util.ArrayList; |
| import java.util.Arrays; |
| import java.util.Collections; |
| import java.util.Iterator; |
| import java.util.List; |
| import java.util.Set; |
| |
| /** |
| * @author Daniel Kuppitz (http://gremlin.guru) |
| */ |
| public final class CoalesceStep<S, E> extends FlatMapStep<S, E> implements TraversalParent { |
| |
| private List<Traversal.Admin<S, E>> coalesceTraversals; |
| |
| @SafeVarargs |
| public CoalesceStep(final Traversal.Admin traversal, final Traversal.Admin<S, E>... coalesceTraversals) { |
| super(traversal); |
| this.coalesceTraversals = Arrays.asList(coalesceTraversals); |
| for (final Traversal.Admin<S, ?> conjunctionTraversal : this.coalesceTraversals) { |
| this.integrateChild(conjunctionTraversal); |
| } |
| } |
| |
| @Override |
| protected Iterator<E> flatMap(final Traverser.Admin<S> traverser) { |
| for (final Traversal.Admin<S, E> coalesceTraversal : this.coalesceTraversals) { |
| coalesceTraversal.reset(); |
| coalesceTraversal.addStart(traverser.split()); |
| if (coalesceTraversal.hasNext()) |
| return coalesceTraversal; |
| } |
| return EmptyIterator.instance(); |
| } |
| |
| @Override |
| public Set<TraverserRequirement> getRequirements() { |
| return this.getSelfAndChildRequirements(); |
| } |
| |
| @Override |
| public List<Traversal.Admin<S, E>> getLocalChildren() { |
| return Collections.unmodifiableList(this.coalesceTraversals); |
| } |
| |
| @Override |
| public CoalesceStep<S, E> clone() { |
| final CoalesceStep<S, E> clone = (CoalesceStep<S, E>) super.clone(); |
| clone.coalesceTraversals = new ArrayList<>(); |
| for (final Traversal.Admin<S, E> conjunctionTraversal : this.coalesceTraversals) { |
| clone.coalesceTraversals.add(conjunctionTraversal.clone()); |
| } |
| return clone; |
| } |
| |
| @Override |
| public void setTraversal(final Traversal.Admin<?, ?> parentTraversal) { |
| super.setTraversal(parentTraversal); |
| for (final Traversal.Admin<S, E> conjunctionTraversal : this.coalesceTraversals) { |
| this.integrateChild(conjunctionTraversal); |
| } |
| } |
| |
| @Override |
| public String toString() { |
| return StringFactory.stepString(this, this.coalesceTraversals); |
| } |
| |
| @Override |
| public int hashCode() { |
| int result = super.hashCode(), i = 0; |
| for (final Traversal.Admin<S, E> traversal : this.coalesceTraversals) { |
| result ^= Integer.rotateLeft(traversal.hashCode(), i++); |
| } |
| return result; |
| } |
| } |