/*
* 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.branch;
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.TraversalParent;
import org.apache.tinkerpop.gremlin.process.traversal.step.util.ComputerAwareStep;
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.iterator.IteratorUtils;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.NoSuchElementException;
import java.util.Set;
/**
* @author Marko A. Rodriguez (http://markorodriguez.com)
*/
public final class RepeatStep<S> extends ComputerAwareStep<S, S> implements TraversalParent {
private Traversal.Admin<S, S> repeatTraversal = null;
private Traversal.Admin<S, ?> untilTraversal = null;
private Traversal.Admin<S, ?> emitTraversal = null;
public boolean untilFirst = false;
public boolean emitFirst = false;
public RepeatStep(final Traversal.Admin traversal) {
super(traversal);
}
@Override
public Set<TraverserRequirement> getRequirements() {
final Set<TraverserRequirement> requirements = this.getSelfAndChildRequirements(TraverserRequirement.BULK);
if (requirements.contains(TraverserRequirement.SINGLE_LOOP))
requirements.add(TraverserRequirement.NESTED_LOOP);
requirements.add(TraverserRequirement.SINGLE_LOOP);
return requirements;
}
@SuppressWarnings("unchecked")
public void setRepeatTraversal(final Traversal.Admin<S, S> repeatTraversal) {
if (null != this.repeatTraversal)
throw new IllegalStateException("The repeat()-step already has its loop section declared: " + this);
this.repeatTraversal = repeatTraversal; // .clone();
this.repeatTraversal.addStep(new RepeatEndStep(this.repeatTraversal));
this.integrateChild(this.repeatTraversal);
}
public void setUntilTraversal(final Traversal.Admin<S, ?> untilTraversal) {
if (null != this.untilTraversal)
throw new IllegalStateException("The repeat()-step already has its until()-modulator declared: " + this);
if (null == this.repeatTraversal) this.untilFirst = true;
this.untilTraversal = this.integrateChild(untilTraversal);
}
public Traversal.Admin<S, ?> getUntilTraversal() {
return this.untilTraversal;
}
public void setEmitTraversal(final Traversal.Admin<S, ?> emitTraversal) {
if (null != this.emitTraversal)
throw new IllegalStateException("The repeat()-step already has its emit()-modulator declared: " + this);
if (null == this.repeatTraversal) this.emitFirst = true;
this.emitTraversal = this.integrateChild(emitTraversal);
}
public Traversal.Admin<S, ?> getEmitTraversal() {
return this.emitTraversal;
}
public Traversal.Admin<S, S> getRepeatTraversal() {
return this.repeatTraversal;
}
public List<Traversal.Admin<S, S>> getGlobalChildren() {
return null == this.repeatTraversal ? Collections.emptyList() : Collections.singletonList(this.repeatTraversal);
}
public List<Traversal.Admin<S, ?>> getLocalChildren() {
final List<Traversal.Admin<S, ?>> list = new ArrayList<>(2);
if (null != this.untilTraversal)
list.add(this.untilTraversal);
if (null != this.emitTraversal)
list.add(this.emitTraversal);
return list;
}
public final boolean doUntil(final Traverser.Admin<S> traverser, boolean utilFirst) {
return utilFirst == this.untilFirst && null != this.untilTraversal && TraversalUtil.test(traverser, this.untilTraversal);
}
public final boolean doEmit(final Traverser.Admin<S> traverser, boolean emitFirst) {
return emitFirst == this.emitFirst && null != this.emitTraversal && TraversalUtil.test(traverser, this.emitTraversal);
}
@Override
public String toString() {
if (this.untilFirst && this.emitFirst)
return StringFactory.stepString(this, untilString(), emitString(), this.repeatTraversal);
else if (this.emitFirst)
return StringFactory.stepString(this, emitString(), this.repeatTraversal, untilString());
else if (this.untilFirst)
return StringFactory.stepString(this, untilString(), this.repeatTraversal, emitString());
else
return StringFactory.stepString(this, this.repeatTraversal, untilString(), emitString());
}
@Override
public void reset() {
super.reset();
if (null != this.emitTraversal)
this.emitTraversal.reset();
if (null != this.untilTraversal)
this.untilTraversal.reset();
if (null != this.repeatTraversal)
this.repeatTraversal.reset();
}
private final String untilString() {
return null == this.untilTraversal ? "until(false)" : "until(" + this.untilTraversal + ')';
}
private final String emitString() {
return null == this.emitTraversal ? "emit(false)" : "emit(" + this.emitTraversal + ')';
}
/////////////////////////
@Override
public RepeatStep<S> clone() {
final RepeatStep<S> clone = (RepeatStep<S>) super.clone();
clone.repeatTraversal = this.repeatTraversal.clone();
if (null != this.untilTraversal)
clone.untilTraversal = this.untilTraversal.clone();
if (null != this.emitTraversal)
clone.emitTraversal = this.emitTraversal.clone();
return clone;
}
@Override
public void setTraversal(final Traversal.Admin<?, ?> parentTraversal) {
super.setTraversal(parentTraversal);
this.integrateChild(this.repeatTraversal);
this.integrateChild(this.untilTraversal);
this.integrateChild(this.emitTraversal);
}
@Override
public int hashCode() {
int result = super.hashCode() ^ this.repeatTraversal.hashCode();
result ^= Boolean.hashCode(this.untilFirst);
result ^= Boolean.hashCode(this.emitFirst) << 1;
if (this.untilTraversal != null)
result ^= this.untilTraversal.hashCode();
if (this.emitTraversal != null)
result ^= this.emitTraversal.hashCode();
return result;
}
@Override
protected Iterator<Traverser.Admin<S>> standardAlgorithm() throws NoSuchElementException {
while (true) {
if (this.repeatTraversal.getEndStep().hasNext()) {
return this.repeatTraversal.getEndStep();
} else {
final Traverser.Admin<S> start = this.starts.next();
if (doUntil(start, true)) {
start.resetLoops();
return IteratorUtils.of(start);
}
this.repeatTraversal.addStart(start);
if (doEmit(start, true)) {
final Traverser.Admin<S> emitSplit = start.split();
emitSplit.resetLoops();
return IteratorUtils.of(emitSplit);
}
}
}
}
@Override
protected Iterator<Traverser.Admin<S>> computerAlgorithm() throws NoSuchElementException {
final Traverser.Admin<S> start = this.starts.next();
if (doUntil(start, true)) {
start.resetLoops();
start.setStepId(this.getNextStep().getId());
start.addLabels(this.labels);
return IteratorUtils.of(start);
} else {
start.setStepId(this.repeatTraversal.getStartStep().getId());
if (doEmit(start, true)) {
final Traverser.Admin<S> emitSplit = start.split();
emitSplit.resetLoops();
emitSplit.setStepId(this.getNextStep().getId());
return IteratorUtils.of(start, emitSplit);
} else {
return IteratorUtils.of(start);
}
}
}
/////////////////////////
public static <A, B, C extends Traversal<A, B>> C addRepeatToTraversal(final C traversal, final Traversal.Admin<B, B> repeatTraversal) {
final Step<?, B> step = traversal.asAdmin().getEndStep();
if (step instanceof RepeatStep && null == ((RepeatStep) step).repeatTraversal) {
((RepeatStep<B>) step).setRepeatTraversal(repeatTraversal);
} else {
final RepeatStep<B> repeatStep = new RepeatStep<>(traversal.asAdmin());
repeatStep.setRepeatTraversal(repeatTraversal);
traversal.asAdmin().addStep(repeatStep);
}
return traversal;
}
public static <A, B, C extends Traversal<A, B>> C addUntilToTraversal(final C traversal, final Traversal.Admin<B, ?> untilPredicate) {
final Step<?, B> step = traversal.asAdmin().getEndStep();
if (step instanceof RepeatStep && null == ((RepeatStep) step).untilTraversal) {
((RepeatStep<B>) step).setUntilTraversal(untilPredicate);
} else {
final RepeatStep<B> repeatStep = new RepeatStep<>(traversal.asAdmin());
repeatStep.setUntilTraversal(untilPredicate);
traversal.asAdmin().addStep(repeatStep);
}
return traversal;
}
public static <A, B, C extends Traversal<A, B>> C addEmitToTraversal(final C traversal, final Traversal.Admin<B, ?> emitPredicate) {
final Step<?, B> step = traversal.asAdmin().getEndStep();
if (step instanceof RepeatStep && null == ((RepeatStep) step).emitTraversal) {
((RepeatStep<B>) step).setEmitTraversal(emitPredicate);
} else {
final RepeatStep<B> repeatStep = new RepeatStep<>(traversal.asAdmin());
repeatStep.setEmitTraversal(emitPredicate);
traversal.asAdmin().addStep(repeatStep);
}
return traversal;
}
///////////////////////////////////
public static class RepeatEndStep<S> extends ComputerAwareStep<S, S> {
public RepeatEndStep(final Traversal.Admin traversal) {
super(traversal);
}
@Override
protected Iterator<Traverser.Admin<S>> standardAlgorithm() throws NoSuchElementException {
final RepeatStep<S> repeatStep = (RepeatStep<S>) this.getTraversal().getParent();
while (true) {
final Traverser.Admin<S> start = this.starts.next();
start.incrLoops(this.getId());
if (repeatStep.doUntil(start, false)) {
start.resetLoops();
return IteratorUtils.of(start);
} else {
if (!repeatStep.untilFirst && !repeatStep.emitFirst)
repeatStep.repeatTraversal.addStart(start);
else
repeatStep.addStart(start);
if (repeatStep.doEmit(start, false)) {
final Traverser.Admin<S> emitSplit = start.split();
emitSplit.resetLoops();
return IteratorUtils.of(emitSplit);
}
}
}
}
@Override
protected Iterator<Traverser.Admin<S>> computerAlgorithm() throws NoSuchElementException {
final RepeatStep<S> repeatStep = (RepeatStep<S>) this.getTraversal().getParent();
final Traverser.Admin<S> start = this.starts.next();
start.incrLoops(repeatStep.getId());
if (repeatStep.doUntil(start, false)) {
start.resetLoops();
start.setStepId(repeatStep.getNextStep().getId());
start.addLabels(repeatStep.labels);
return IteratorUtils.of(start);
} else {
start.setStepId(repeatStep.getId());
if (repeatStep.doEmit(start, false)) {
final Traverser.Admin<S> emitSplit = start.split();
emitSplit.resetLoops();
emitSplit.setStepId(repeatStep.getNextStep().getId());
emitSplit.addLabels(repeatStep.labels);
return IteratorUtils.of(start, emitSplit);
}
return IteratorUtils.of(start);
}
}
}
}