| /* |
| * 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.ByModulating; |
| import org.apache.tinkerpop.gremlin.process.traversal.step.TraversalParent; |
| import org.apache.tinkerpop.gremlin.process.traversal.step.util.MapHelper; |
| import org.apache.tinkerpop.gremlin.process.traversal.step.util.ReducingBarrierStep; |
| import org.apache.tinkerpop.gremlin.process.traversal.traverser.TraverserRequirement; |
| import org.apache.tinkerpop.gremlin.process.traversal.util.TraversalUtil; |
| import org.apache.tinkerpop.gremlin.structure.util.StringFactory; |
| import org.apache.tinkerpop.gremlin.util.function.HashMapSupplier; |
| |
| import java.io.Serializable; |
| import java.util.Collections; |
| import java.util.HashMap; |
| import java.util.List; |
| import java.util.Map; |
| import java.util.Set; |
| import java.util.function.BinaryOperator; |
| |
| /** |
| * @author Marko A. Rodriguez (http://markorodriguez.com) |
| */ |
| public final class GroupCountStep<S, E> extends ReducingBarrierStep<S, Map<E, Long>> implements TraversalParent, ByModulating { |
| |
| private Traversal.Admin<S, E> keyTraversal = null; |
| |
| public GroupCountStep(final Traversal.Admin traversal) { |
| super(traversal); |
| this.setSeedSupplier(HashMapSupplier.instance()); |
| this.setReducingBiOperator(GroupCountBiOperator.instance()); |
| } |
| |
| @Override |
| public Map<E, Long> projectTraverser(final Traverser.Admin<S> traverser) { |
| final Map<E, Long> map = new HashMap<>(1); |
| map.put(TraversalUtil.applyNullable(traverser, this.keyTraversal), traverser.bulk()); |
| return map; |
| } |
| |
| @Override |
| public void addLocalChild(final Traversal.Admin<?, ?> groupTraversal) { |
| this.keyTraversal = this.integrateChild(groupTraversal); |
| } |
| |
| @Override |
| public List<Traversal.Admin<S, E>> getLocalChildren() { |
| return null == this.keyTraversal ? Collections.emptyList() : Collections.singletonList(this.keyTraversal); |
| } |
| |
| @Override |
| public Set<TraverserRequirement> getRequirements() { |
| return this.getSelfAndChildRequirements(TraverserRequirement.BULK); |
| } |
| |
| @Override |
| public void modulateBy(final Traversal.Admin<?, ?> keyTraversal) throws UnsupportedOperationException { |
| this.keyTraversal = this.integrateChild(keyTraversal); |
| } |
| |
| @Override |
| public GroupCountStep<S, E> clone() { |
| final GroupCountStep<S, E> clone = (GroupCountStep<S, E>) super.clone(); |
| if (null != this.keyTraversal) |
| clone.keyTraversal = this.keyTraversal.clone(); |
| return clone; |
| } |
| |
| @Override |
| public void setTraversal(final Traversal.Admin<?, ?> parentTraversal) { |
| super.setTraversal(parentTraversal); |
| integrateChild(this.keyTraversal); |
| } |
| |
| @Override |
| public int hashCode() { |
| int result = super.hashCode(); |
| if (this.keyTraversal != null) result ^= this.keyTraversal.hashCode(); |
| return result; |
| } |
| |
| @Override |
| public String toString() { |
| return StringFactory.stepString(this, this.keyTraversal); |
| } |
| |
| /////////////////////////// |
| |
| public static final class GroupCountBiOperator<E> implements BinaryOperator<Map<E, Long>>, Serializable { |
| |
| private static final GroupCountBiOperator INSTANCE = new GroupCountBiOperator(); |
| |
| @Override |
| public Map<E, Long> apply(final Map<E, Long> mutatingSeed, final Map<E, Long> map) { |
| for (final Map.Entry<E, Long> entry : map.entrySet()) { |
| MapHelper.incr(mutatingSeed, entry.getKey(), entry.getValue()); |
| } |
| return mutatingSeed; |
| } |
| |
| public static final <E> GroupCountBiOperator<E> instance() { |
| return INSTANCE; |
| } |
| } |
| } |