| /* |
| * 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.commons.lang3.ArrayUtils; |
| import org.apache.tinkerpop.gremlin.process.traversal.Compare; |
| import org.apache.tinkerpop.gremlin.process.traversal.Contains; |
| import org.apache.tinkerpop.gremlin.process.traversal.Step; |
| import org.apache.tinkerpop.gremlin.process.traversal.Traversal; |
| import org.apache.tinkerpop.gremlin.process.traversal.Traverser; |
| import org.apache.tinkerpop.gremlin.process.traversal.step.Configuring; |
| import org.apache.tinkerpop.gremlin.process.traversal.step.GraphComputing; |
| import org.apache.tinkerpop.gremlin.process.traversal.step.util.AbstractStep; |
| import org.apache.tinkerpop.gremlin.process.traversal.step.util.HasContainer; |
| import org.apache.tinkerpop.gremlin.process.traversal.step.util.Parameters; |
| import org.apache.tinkerpop.gremlin.process.traversal.util.FastNoSuchElementException; |
| import org.apache.tinkerpop.gremlin.structure.Edge; |
| import org.apache.tinkerpop.gremlin.structure.Element; |
| import org.apache.tinkerpop.gremlin.structure.T; |
| import org.apache.tinkerpop.gremlin.structure.Vertex; |
| import org.apache.tinkerpop.gremlin.structure.util.CloseableIterator; |
| import org.apache.tinkerpop.gremlin.structure.util.StringFactory; |
| import org.apache.tinkerpop.gremlin.util.iterator.EmptyIterator; |
| |
| import java.util.Arrays; |
| import java.util.Collection; |
| import java.util.Collections; |
| import java.util.Iterator; |
| import java.util.function.Supplier; |
| |
| /** |
| * @author Marko A. Rodriguez (http://markorodriguez.com) |
| * @author Pieter Martin |
| */ |
| public class GraphStep<S, E extends Element> extends AbstractStep<S, E> implements GraphComputing, AutoCloseable, Configuring { |
| |
| protected Parameters parameters = new Parameters(); |
| protected final Class<E> returnClass; |
| protected Object[] ids; |
| protected transient Supplier<Iterator<E>> iteratorSupplier; |
| protected boolean isStart; |
| protected boolean done = false; |
| private Traverser.Admin<S> head = null; |
| private Iterator<E> iterator = EmptyIterator.instance(); |
| |
| |
| public GraphStep(final Traversal.Admin traversal, final Class<E> returnClass, final boolean isStart, final Object... ids) { |
| super(traversal); |
| this.returnClass = returnClass; |
| this.ids = (ids != null && ids.length == 1 && ids[0] instanceof Collection) ? ((Collection) ids[0]).toArray(new Object[((Collection) ids[0]).size()]) : ids; |
| this.isStart = isStart; |
| this.iteratorSupplier = () -> (Iterator<E>) (Vertex.class.isAssignableFrom(this.returnClass) ? |
| this.getTraversal().getGraph().get().vertices(this.ids) : |
| this.getTraversal().getGraph().get().edges(this.ids)); |
| } |
| |
| public String toString() { |
| return StringFactory.stepString(this, this.returnClass.getSimpleName().toLowerCase(), Arrays.toString(this.ids)); |
| } |
| |
| @Override |
| public Parameters getParameters() { |
| return this.parameters; |
| } |
| |
| @Override |
| public void configure(final Object... keyValues) { |
| this.parameters.set(null, keyValues); |
| } |
| |
| public Class<E> getReturnClass() { |
| return this.returnClass; |
| } |
| |
| public boolean isStartStep() { |
| return this.isStart; |
| } |
| |
| public static boolean isStartStep(final Step<?, ?> step) { |
| return step instanceof GraphStep && ((GraphStep) step).isStart; |
| } |
| |
| public boolean returnsVertex() { |
| return this.returnClass.equals(Vertex.class); |
| } |
| |
| public boolean returnsEdge() { |
| return this.returnClass.equals(Edge.class); |
| } |
| |
| public void setIteratorSupplier(final Supplier<Iterator<E>> iteratorSupplier) { |
| this.iteratorSupplier = iteratorSupplier; |
| } |
| |
| public Object[] getIds() { |
| return this.ids; |
| } |
| |
| public void addIds(final Object... newIds) { |
| if ((this.ids == null || this.ids.length == 0) && |
| newIds.length == 1 && |
| newIds[0] instanceof Collection && ((Collection) newIds[0]).isEmpty()) |
| this.ids = null; |
| else |
| this.ids = ArrayUtils.addAll(this.ids, |
| (newIds.length == 1 && newIds[0] instanceof Collection) ? |
| ((Collection) newIds[0]).toArray(new Object[((Collection) newIds[0]).size()]) : |
| newIds); |
| } |
| |
| public void clearIds() { |
| this.ids = new Object[0]; |
| } |
| |
| @Override |
| public void onGraphComputer() { |
| this.iteratorSupplier = Collections::emptyIterator; |
| convertElementsToIds(); |
| } |
| |
| public void convertElementsToIds() { |
| if (null != this.ids) { |
| for (int i = 0; i < this.ids.length; i++) { // if this is going to OLAP, convert to ids so you don't serialize elements |
| if (this.ids[i] instanceof Element) |
| this.ids[i] = ((Element) this.ids[i]).id(); |
| } |
| } |
| } |
| |
| @Override |
| protected Traverser.Admin<E> processNextStart() { |
| while (true) { |
| if (this.iterator.hasNext()) { |
| return this.isStart ? this.getTraversal().getTraverserGenerator().generate(this.iterator.next(), (Step) this, 1l) : this.head.split(this.iterator.next(), this); |
| } else { |
| if (this.isStart) { |
| if (this.done) |
| throw FastNoSuchElementException.instance(); |
| else { |
| this.done = true; |
| this.iterator = null == this.iteratorSupplier ? EmptyIterator.instance() : this.iteratorSupplier.get(); |
| } |
| } else { |
| this.head = this.starts.next(); |
| this.iterator = null == this.iteratorSupplier ? EmptyIterator.instance() : this.iteratorSupplier.get(); |
| } |
| } |
| } |
| } |
| |
| @Override |
| public void reset() { |
| super.reset(); |
| this.head = null; |
| this.done = false; |
| this.iterator = EmptyIterator.instance(); |
| } |
| |
| @Override |
| public int hashCode() { |
| int result = super.hashCode() ^ this.returnClass.hashCode(); |
| if (null != this.ids) { |
| for (final Object id : this.ids) { |
| result ^= id.hashCode(); |
| } |
| } |
| return result; |
| } |
| |
| /** |
| * Attempts to close an underlying iterator if it is of type {@link CloseableIterator}. Graph providers may choose |
| * to return this interface containing their vertices and edges if there are expensive resources that might need to |
| * be released at some point. |
| */ |
| @Override |
| public void close() { |
| CloseableIterator.closeIterator(iterator); |
| } |
| |
| /** |
| * Helper method for providers that want to "fold in" {@link HasContainer}'s based on id checking into the ids of the {@link GraphStep}. |
| * |
| * @param graphStep the GraphStep to potentially {@link GraphStep#addIds(Object...)}. |
| * @param hasContainer The {@link HasContainer} to check for id validation. |
| * @return true if the {@link HasContainer} updated ids and thus, was processed. |
| */ |
| public static boolean processHasContainerIds(final GraphStep<?, ?> graphStep, final HasContainer hasContainer) { |
| if (hasContainer.getKey().equals(T.id.getAccessor()) && graphStep.ids.length == 0 && |
| (hasContainer.getBiPredicate() == Compare.eq || hasContainer.getBiPredicate() == Contains.within)) { |
| graphStep.addIds(hasContainer.getValue()); |
| return true; |
| } |
| return false; |
| } |
| } |