/*
* 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.filter;
import org.apache.tinkerpop.gremlin.process.computer.MemoryComputeKey;
import org.apache.tinkerpop.gremlin.process.traversal.Operator;
import org.apache.tinkerpop.gremlin.process.traversal.Pop;
import org.apache.tinkerpop.gremlin.process.traversal.Traversal;
import org.apache.tinkerpop.gremlin.process.traversal.Traverser;
import org.apache.tinkerpop.gremlin.process.traversal.step.Barrier;
import org.apache.tinkerpop.gremlin.process.traversal.step.ByModulating;
import org.apache.tinkerpop.gremlin.process.traversal.step.GraphComputing;
import org.apache.tinkerpop.gremlin.process.traversal.step.PathProcessor;
import org.apache.tinkerpop.gremlin.process.traversal.step.Scoping;
import org.apache.tinkerpop.gremlin.process.traversal.step.TraversalParent;
import org.apache.tinkerpop.gremlin.process.traversal.traverser.TraverserRequirement;
import org.apache.tinkerpop.gremlin.process.traversal.util.FastNoSuchElementException;
import org.apache.tinkerpop.gremlin.process.traversal.util.TraversalUtil;
import org.apache.tinkerpop.gremlin.structure.util.StringFactory;
import org.apache.tinkerpop.gremlin.structure.util.detached.DetachedFactory;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.Set;
import java.util.function.BinaryOperator;
/**
* @author Marko A. Rodriguez (http://markorodriguez.com)
*/
public final class DedupGlobalStep<S> extends FilterStep<S> implements TraversalParent, Scoping, GraphComputing, Barrier<Map<Object, Traverser.Admin<S>>>, ByModulating, PathProcessor {
private Traversal.Admin<S, Object> dedupTraversal = null;
private Set<Object> duplicateSet = new HashSet<>();
private boolean onGraphComputer = false;
private final Set<String> dedupLabels;
private Set<String> keepLabels;
private boolean executingAtMaster = false;
private Map<Object, Traverser.Admin<S>> barrier;
private Iterator<Map.Entry<Object, Traverser.Admin<S>>> barrierIterator;
public DedupGlobalStep(final Traversal.Admin traversal, final String... dedupLabels) {
super(traversal);
this.dedupLabels = dedupLabels.length == 0 ? null : Collections.unmodifiableSet(new HashSet<>(Arrays.asList(dedupLabels)));
}
@Override
protected boolean filter(final Traverser.Admin<S> traverser) {
if (this.onGraphComputer && !this.executingAtMaster) return true;
traverser.setBulk(1L);
if (null == this.dedupLabels) {
return this.duplicateSet.add(TraversalUtil.applyNullable(traverser, this.dedupTraversal));
} else {
final List<Object> objects = new ArrayList<>(this.dedupLabels.size());
this.dedupLabels.forEach(label -> objects.add(TraversalUtil.applyNullable((S) this.getScopeValue(Pop.last, label, traverser), this.dedupTraversal)));
return this.duplicateSet.add(objects);
}
}
@Override
public void atMaster(final boolean atMaster) {
this.executingAtMaster = atMaster;
}
@Override
public ElementRequirement getMaxRequirement() {
return null == this.dedupLabels ? ElementRequirement.ID : PathProcessor.super.getMaxRequirement();
}
@Override
protected Traverser.Admin<S> processNextStart() {
if (null != this.barrier) {
this.barrierIterator = this.barrier.entrySet().iterator();
this.barrier = null;
}
while (this.barrierIterator != null && this.barrierIterator.hasNext()) {
if (null == this.barrierIterator)
this.barrierIterator = this.barrier.entrySet().iterator();
final Map.Entry<Object, Traverser.Admin<S>> entry = this.barrierIterator.next();
if (this.duplicateSet.add(entry.getKey()))
return PathProcessor.processTraverserPathLabels(entry.getValue(), this.keepLabels);
}
return PathProcessor.processTraverserPathLabels(super.processNextStart(), this.keepLabels);
}
@Override
public List<Traversal<S, Object>> getLocalChildren() {
return null == this.dedupTraversal ? Collections.emptyList() : Collections.singletonList(this.dedupTraversal);
}
@Override
public void modulateBy(final Traversal.Admin<?, ?> dedupTraversal) {
this.dedupTraversal = this.integrateChild(dedupTraversal);
}
@Override
public DedupGlobalStep<S> clone() {
final DedupGlobalStep<S> clone = (DedupGlobalStep<S>) super.clone();
clone.duplicateSet = new HashSet<>();
if (null != this.dedupTraversal)
clone.dedupTraversal = this.dedupTraversal.clone();
return clone;
}
@Override
public void setTraversal(final Traversal.Admin<?, ?> parentTraversal) {
super.setTraversal(parentTraversal);
this.integrateChild(this.dedupTraversal);
}
@Override
public int hashCode() {
int result = super.hashCode();
if (this.dedupTraversal != null)
result ^= this.dedupTraversal.hashCode();
if (this.dedupLabels != null)
result ^= this.dedupLabels.hashCode();
return result;
}
@Override
public void reset() {
super.reset();
this.duplicateSet.clear();
this.barrier = null;
this.barrierIterator = null;
}
@Override
public String toString() {
return StringFactory.stepString(this, this.dedupLabels, this.dedupTraversal);
}
@Override
public Set<TraverserRequirement> getRequirements() {
return this.dedupLabels == null ?
this.getSelfAndChildRequirements(TraverserRequirement.BULK) :
this.getSelfAndChildRequirements(TraverserRequirement.LABELED_PATH, TraverserRequirement.BULK);
}
@Override
public void onGraphComputer() {
this.onGraphComputer = true;
}
@Override
public Set<String> getScopeKeys() {
return null == this.dedupLabels ? Collections.emptySet() : this.dedupLabels;
}
@Override
public void processAllStarts() {
}
@Override
public boolean hasNextBarrier() {
return null != this.barrier || this.starts.hasNext();
}
@Override
public Map<Object, Traverser.Admin<S>> nextBarrier() throws NoSuchElementException {
final Map<Object, Traverser.Admin<S>> map = null != this.barrier ? this.barrier : new HashMap<>();
while (this.starts.hasNext()) {
final Traverser.Admin<S> traverser = this.starts.next();
final Object object;
if (null != this.dedupLabels) {
object = new ArrayList<>(this.dedupLabels.size());
for (final String label : this.dedupLabels) {
((List) object).add(TraversalUtil.applyNullable((S) this.getScopeValue(Pop.last, label, traverser), this.dedupTraversal));
}
} else {
object = TraversalUtil.applyNullable(traverser, this.dedupTraversal);
}
if (!map.containsKey(object)) {
traverser.setBulk(1L);
// traverser.detach();
traverser.set(DetachedFactory.detach(traverser.get(), true)); // TODO: detect required detachment accordingly
map.put(object, traverser);
}
}
this.barrier = null;
this.barrierIterator = null;
if (map.isEmpty())
throw FastNoSuchElementException.instance();
else
return map;
}
@Override
public void addBarrier(final Map<Object, Traverser.Admin<S>> barrier) {
if (null == this.barrier)
this.barrier = new HashMap<>(barrier);
else
this.barrier.putAll(barrier);
}
@Override
public MemoryComputeKey<Map<Object, Traverser.Admin<S>>> getMemoryComputeKey() {
return MemoryComputeKey.of(this.getId(), (BinaryOperator) Operator.addAll, false, true);
}
@Override
public void setKeepLabels(Set<String> labels) {
this.keepLabels = labels;
}
@Override
public Set<String> getKeepLabels() {
return this.keepLabels;
}
}