| /* |
| * 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.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.Bypassing; |
| import org.apache.tinkerpop.gremlin.process.traversal.step.Ranging; |
| import org.apache.tinkerpop.gremlin.process.traversal.traverser.TraverserRequirement; |
| import org.apache.tinkerpop.gremlin.process.traversal.traverser.util.TraverserSet; |
| import org.apache.tinkerpop.gremlin.process.traversal.util.FastNoSuchElementException; |
| import org.apache.tinkerpop.gremlin.structure.util.CloseableIterator; |
| import org.apache.tinkerpop.gremlin.structure.util.StringFactory; |
| import org.apache.tinkerpop.gremlin.util.iterator.IteratorUtils; |
| |
| import java.io.Serializable; |
| import java.util.Collections; |
| import java.util.NoSuchElementException; |
| import java.util.Set; |
| import java.util.concurrent.atomic.AtomicLong; |
| import java.util.function.BinaryOperator; |
| |
| /** |
| * @author Bob Briody (http://bobbriody.com) |
| * @author Marko A. Rodriguez (http://markorodriguez.com) |
| */ |
| public final class RangeGlobalStep<S> extends FilterStep<S> implements Ranging, Bypassing, Barrier<TraverserSet<S>> { |
| |
| private long low; |
| private final long high; |
| private AtomicLong counter = new AtomicLong(0l); |
| private boolean bypass; |
| |
| public RangeGlobalStep(final Traversal.Admin traversal, final long low, final long high) { |
| super(traversal); |
| if (low != -1 && high != -1 && low > high) { |
| throw new IllegalArgumentException("Not a legal range: [" + low + ", " + high + ']'); |
| } |
| this.low = low; |
| this.high = high; |
| } |
| |
| @Override |
| protected boolean filter(final Traverser.Admin<S> traverser) { |
| if (this.bypass) return true; |
| |
| if (this.high != -1 && this.counter.get() >= this.high) { |
| // This is a global step and this place would be the end of the traversal. |
| // Close the traversal to free up resources. |
| CloseableIterator.closeIterator(traversal); |
| throw FastNoSuchElementException.instance(); |
| } |
| |
| long avail = traverser.bulk(); |
| if (this.counter.get() + avail <= this.low) { |
| // Will not surpass the low w/ this traverser. Skip and filter the whole thing. |
| this.counter.getAndAdd(avail); |
| return false; |
| } |
| |
| // Skip for the low and trim for the high. Both can happen at once. |
| |
| long toSkip = 0; |
| if (this.counter.get() < this.low) { |
| toSkip = this.low - this.counter.get(); |
| } |
| |
| long toTrim = 0; |
| if (this.high != -1 && this.counter.get() + avail >= this.high) { |
| toTrim = this.counter.get() + avail - this.high; |
| } |
| |
| long toEmit = avail - toSkip - toTrim; |
| this.counter.getAndAdd(toSkip + toEmit); |
| traverser.setBulk(toEmit); |
| |
| return true; |
| } |
| |
| @Override |
| public void reset() { |
| super.reset(); |
| this.counter.set(0l); |
| } |
| |
| @Override |
| public String toString() { |
| return StringFactory.stepString(this, this.low, this.high); |
| } |
| |
| @Override |
| public long getLowRange() { |
| return this.low; |
| } |
| |
| @Override |
| public long getHighRange() { |
| return this.high; |
| } |
| |
| @Override |
| public RangeGlobalStep<S> clone() { |
| final RangeGlobalStep<S> clone = (RangeGlobalStep<S>) super.clone(); |
| clone.counter = new AtomicLong(0l); |
| return clone; |
| } |
| |
| @Override |
| public int hashCode() { |
| return super.hashCode() ^ Long.hashCode(this.low) ^ Long.hashCode(this.high); |
| } |
| |
| @Override |
| public boolean equals(final Object other) { |
| if (super.equals(other)) { |
| final RangeGlobalStep typedOther = (RangeGlobalStep) other; |
| return typedOther.low == this.low && typedOther.high == this.high; |
| } |
| return false; |
| } |
| |
| @Override |
| public Set<TraverserRequirement> getRequirements() { |
| return Collections.singleton(TraverserRequirement.BULK); |
| } |
| |
| |
| @Override |
| public MemoryComputeKey<TraverserSet<S>> getMemoryComputeKey() { |
| return MemoryComputeKey.of(this.getId(), new RangeBiOperator<>(this.high), false, true); |
| } |
| |
| @Override |
| public void setBypass(final boolean bypass) { |
| this.bypass = bypass; |
| } |
| |
| @Override |
| public void processAllStarts() { |
| |
| } |
| |
| @Override |
| public boolean hasNextBarrier() { |
| return this.starts.hasNext(); |
| } |
| |
| @Override |
| public TraverserSet<S> nextBarrier() throws NoSuchElementException { |
| if(!this.starts.hasNext()) |
| throw FastNoSuchElementException.instance(); |
| final TraverserSet<S> barrier = (TraverserSet<S>) this.traversal.getTraverserSetSupplier().get(); |
| while (this.starts.hasNext()) { |
| barrier.add(this.starts.next()); |
| } |
| return barrier; |
| } |
| |
| @Override |
| public void addBarrier(final TraverserSet<S> barrier) { |
| IteratorUtils.removeOnNext(barrier.iterator()).forEachRemaining(traverser -> { |
| traverser.setSideEffects(this.getTraversal().getSideEffects()); |
| this.addStart(traverser); |
| }); |
| } |
| |
| //////////////// |
| |
| public static final class RangeBiOperator<S> implements BinaryOperator<TraverserSet<S>>, Serializable { |
| |
| private final long highRange; |
| |
| public RangeBiOperator() { |
| this(-1); |
| } |
| |
| public RangeBiOperator(final long highRange) { |
| this.highRange = highRange; |
| } |
| |
| @Override |
| public TraverserSet<S> apply(final TraverserSet<S> mutatingSeed, final TraverserSet<S> set) { |
| if (this.highRange == -1 || mutatingSeed.size() < this.highRange) |
| mutatingSeed.addAll(set); |
| return mutatingSeed; |
| } |
| } |
| } |