/*
* 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.BulkSet;
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.TraversalHelper;
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.ArrayList;
import java.util.Collection;
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)
* @deprecated As of release 3.1.0, replaced by {@link GroupStep}.
*/
public final class GroupStepV3d0<S, K, V, R> extends ReducingBarrierStep<S, Map<K, R>> implements TraversalParent, ByModulating {
private char state = 'k';
private Traversal.Admin<S, K> keyTraversal = null;
private Traversal.Admin<S, V> valueTraversal = null;
private Traversal.Admin<Collection<V>, R> reduceTraversal = null;
public GroupStepV3d0(final Traversal.Admin traversal) {
super(traversal);
this.setSeedSupplier(HashMapSupplier.instance());
this.setReducingBiOperator(GroupBiOperatorV3d0.instance());
}
@Override
public Map<K, R> projectTraverser(final Traverser.Admin<S> traverser) {
final K key = TraversalUtil.applyNullable(traverser, this.keyTraversal);
final BulkSet<V> values = new BulkSet<>();
final V value = TraversalUtil.applyNullable(traverser, this.valueTraversal);
TraversalHelper.addToCollectionUnrollIterator(values, value, traverser.bulk());
return Collections.singletonMap(key, (R) values);
}
@Override
public String toString() {
return StringFactory.stepString(this, this.keyTraversal, this.valueTraversal, this.reduceTraversal);
}
@Override
public Map<K, R> generateFinalResult(final Map<K, R> valueMap) {
final Map<K, R> reducedMap = new HashMap<>();
for (final K key : valueMap.keySet()) {
final R r = TraversalUtil.applyNullable(((Map<K, Collection<V>>) valueMap).get(key), this.reduceTraversal);
reducedMap.put(key, r);
}
return reducedMap;
}
@Override
public <A, B> List<Traversal.Admin<A, B>> getLocalChildren() {
final List<Traversal.Admin<A, B>> children = new ArrayList<>(3);
if (null != this.keyTraversal)
children.add((Traversal.Admin) this.keyTraversal);
if (null != this.valueTraversal)
children.add((Traversal.Admin) this.valueTraversal);
if (null != this.reduceTraversal)
children.add((Traversal.Admin) this.reduceTraversal);
return children;
}
@Override
public void modulateBy(final Traversal.Admin<?, ?> kvrTraversal) {
if ('k' == this.state) {
this.keyTraversal = this.integrateChild(kvrTraversal);
this.state = 'v';
} else if ('v' == this.state) {
this.valueTraversal = this.integrateChild(kvrTraversal);
this.state = 'r';
} else if ('r' == this.state) {
this.reduceTraversal = this.integrateChild(kvrTraversal);
this.state = 'x';
} else {
throw new IllegalStateException("The key, value, and reduce functions for group()-step have already been set");
}
}
@Override
public Set<TraverserRequirement> getRequirements() {
return this.getSelfAndChildRequirements(TraverserRequirement.SIDE_EFFECTS, TraverserRequirement.BULK);
}
@Override
public GroupStepV3d0<S, K, V, R> clone() {
final GroupStepV3d0<S, K, V, R> clone = (GroupStepV3d0<S, K, V, R>) super.clone();
if (null != this.keyTraversal)
clone.keyTraversal = this.keyTraversal.clone();
if (null != this.valueTraversal)
clone.valueTraversal = this.valueTraversal.clone();
if (null != this.reduceTraversal)
clone.reduceTraversal = this.reduceTraversal.clone();
return clone;
}
@Override
public void setTraversal(final Traversal.Admin<?, ?> parentTraversal) {
super.setTraversal(parentTraversal);
integrateChild(this.keyTraversal);
integrateChild(this.valueTraversal);
integrateChild(this.reduceTraversal);
}
@Override
public int hashCode() {
int result = super.hashCode();
if (this.keyTraversal != null) result ^= this.keyTraversal.hashCode();
if (this.valueTraversal != null) result ^= this.valueTraversal.hashCode();
if (this.reduceTraversal != null) result ^= this.reduceTraversal.hashCode();
return result;
}
//////////
@Deprecated
public static class GroupBiOperatorV3d0<K, V> implements BinaryOperator<Map<K, V>>, Serializable {
private final static GroupBiOperatorV3d0 INSTANCE = new GroupBiOperatorV3d0();
@Override
public Map<K, V> apply(final Map<K, V> mutatingSeed, final Map<K, V> map) {
for (final K key : map.keySet()) {
final BulkSet<V> values = (BulkSet<V>) map.get(key);
BulkSet<V> seedValues = (BulkSet<V>) mutatingSeed.get(key);
if (null == seedValues) {
seedValues = new BulkSet<>();
mutatingSeed.put(key, (V) seedValues);
}
seedValues.addAll(values);
}
return mutatingSeed;
}
public static final <K, V> GroupBiOperatorV3d0<K, V> instance() {
return INSTANCE;
}
}
}