| /* |
| * 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.util; |
| |
| import org.apache.tinkerpop.gremlin.process.traversal.Step; |
| import org.apache.tinkerpop.gremlin.process.traversal.Traverser; |
| import org.apache.tinkerpop.gremlin.process.traversal.traverser.util.TraverserSet; |
| |
| import java.io.Serializable; |
| import java.util.Iterator; |
| |
| /** |
| * @author Marko A. Rodriguez (http://markorodriguez.com) |
| */ |
| public final class ExpandableStepIterator<S> implements Iterator<Traverser.Admin<S>>, Serializable { |
| |
| private final TraverserSet<S> traverserSet = new TraverserSet<>(); |
| private final Step<S, ?> hostStep; |
| |
| public ExpandableStepIterator(final Step<S, ?> hostStep) { |
| this.hostStep = hostStep; |
| } |
| |
| @Override |
| public boolean hasNext() { |
| return !this.traverserSet.isEmpty() || this.hostStep.getPreviousStep().hasNext(); |
| } |
| |
| @Override |
| public Traverser.Admin<S> next() { |
| if (!this.traverserSet.isEmpty()) |
| return this.traverserSet.remove(); |
| ///////////// |
| if (this.hostStep.getPreviousStep().hasNext()) |
| return this.hostStep.getPreviousStep().next(); |
| ///////////// |
| return this.traverserSet.remove(); |
| } |
| |
| public void add(final Iterator<Traverser.Admin<S>> iterator) { |
| iterator.forEachRemaining(this.traverserSet::add); |
| } |
| |
| public void add(final Traverser.Admin<S> traverser) { |
| this.traverserSet.add(traverser); |
| } |
| |
| @Override |
| public String toString() { |
| return this.traverserSet.toString(); |
| } |
| |
| public void clear() { |
| this.traverserSet.clear(); |
| } |
| } |