| /* |
| * 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.lambda; |
| |
| import org.apache.tinkerpop.gremlin.process.traversal.Traverser; |
| import org.apache.tinkerpop.gremlin.process.traversal.util.TraversalUtil; |
| import org.apache.tinkerpop.gremlin.structure.Element; |
| |
| import java.util.Map; |
| import java.util.Objects; |
| |
| /** |
| * More efficiently extracts a value from an {@link Element} or {@code Map} to avoid strategy application costs. |
| * |
| * @author Marko A. Rodriguez (http://markorodriguez.com) |
| * @author Stephen Mallette (http://stephen.genoprime.com) |
| */ |
| public final class ValueTraversal<T, V> extends AbstractLambdaTraversal<T, V> { |
| |
| private final String propertyKey; |
| private V value; |
| |
| public ValueTraversal(final String propertyKey) { |
| this.propertyKey = propertyKey; |
| } |
| |
| @Override |
| public V next() { |
| return this.value; |
| } |
| |
| @Override |
| public boolean hasNext() { |
| return true; |
| } |
| |
| @Override |
| public void addStart(final Traverser.Admin<T> start) { |
| if (null == this.bypassTraversal) { |
| final T o = start.get(); |
| if (o instanceof Element) |
| this.value = (V)((Element) o).property(propertyKey).orElse(null); |
| else if (o instanceof Map) |
| this.value = (V) ((Map) o).get(propertyKey); |
| else |
| throw new IllegalStateException(String.format( |
| "The by(\"%s\") modulator can only be applied to a traverser that is an Element or a Map - it is being applied to [%s] a %s class instead", |
| propertyKey, o, o.getClass().getSimpleName())); |
| } else { |
| this.value = TraversalUtil.apply(start, this.bypassTraversal); |
| } |
| } |
| |
| public String getPropertyKey() { |
| return this.propertyKey; |
| } |
| |
| @Override |
| public String toString() { |
| return "value(" + (null == this.bypassTraversal ? this.propertyKey : this.bypassTraversal) + ')'; |
| } |
| |
| @Override |
| public int hashCode() { |
| return super.hashCode() ^ this.propertyKey.hashCode(); |
| } |
| |
| @Override |
| public boolean equals(final Object other) { |
| return other instanceof ValueTraversal |
| && Objects.equals(((ValueTraversal) other).propertyKey, this.propertyKey); |
| } |
| } |