| /* |
| * 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.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.Configuring; |
| import org.apache.tinkerpop.gremlin.process.traversal.step.TraversalParent; |
| import org.apache.tinkerpop.gremlin.process.traversal.step.util.AbstractStep; |
| import org.apache.tinkerpop.gremlin.process.traversal.step.util.Parameters; |
| import org.apache.tinkerpop.gremlin.process.traversal.traverser.TraverserRequirement; |
| import org.apache.tinkerpop.gremlin.process.traversal.traverser.util.DummyTraverser; |
| import org.apache.tinkerpop.gremlin.process.traversal.traverser.util.TraverserSet; |
| import org.apache.tinkerpop.gremlin.process.traversal.util.FastNoSuchElementException; |
| import org.apache.tinkerpop.gremlin.process.traversal.util.TraversalUtil; |
| import org.apache.tinkerpop.gremlin.structure.Graph; |
| import org.apache.tinkerpop.gremlin.structure.service.Service; |
| import org.apache.tinkerpop.gremlin.structure.service.ServiceRegistry; |
| import org.apache.tinkerpop.gremlin.structure.util.CloseableIterator; |
| import org.apache.tinkerpop.gremlin.structure.util.StringFactory; |
| |
| import java.util.ArrayList; |
| import java.util.Collections; |
| import java.util.HashSet; |
| import java.util.LinkedHashMap; |
| import java.util.List; |
| import java.util.Map; |
| import java.util.Set; |
| |
| import static org.apache.tinkerpop.gremlin.structure.util.CloseableIterator.EmptyCloseableIterator; |
| import static org.apache.tinkerpop.gremlin.structure.service.Service.ServiceCallContext; |
| |
| /** |
| * Reference implementation for service calls via the {@link ServiceRegistry} and {@link Service} APIs. This step |
| * can be used to start a traversal or it can be used mid-traversal with one at a time or barrier execution. |
| * |
| * @author Mike Personick (http://github.com/mikepersonick) |
| */ |
| public final class CallStep<S, E> extends AbstractStep<S, E> implements TraversalParent, AutoCloseable, Configuring { |
| |
| private final boolean isStart; |
| private boolean first = true; |
| |
| private ServiceCallContext ctx; |
| private String serviceName; |
| private Service<S, E> service; |
| private Map staticParams; |
| private Traversal.Admin<S,Map> mapTraversal; |
| private Parameters parameters; |
| |
| private transient Traverser.Admin<S> head = null; |
| private transient CloseableIterator iterator = EmptyCloseableIterator.instance(); |
| |
| public CallStep(final Traversal.Admin traversal, final boolean isStart) { |
| this(traversal, isStart, null); |
| } |
| |
| public CallStep(final Traversal.Admin traversal, final boolean isStart, final String service) { |
| this(traversal, isStart, service, null); |
| } |
| |
| public CallStep(final Traversal.Admin traversal, final boolean isStart, final String service, final Map staticParams) { |
| this(traversal, isStart, service, staticParams, null); |
| } |
| |
| public CallStep(final Traversal.Admin traversal, final boolean isStart, final String service, final Map staticParams, |
| final Traversal.Admin<S, Map> mapTraversal) { |
| super(traversal); |
| |
| this.isStart = isStart; |
| this.serviceName = service; |
| this.staticParams = staticParams == null ? new LinkedHashMap() : staticParams; |
| this.mapTraversal = mapTraversal == null ? null : integrateChild(mapTraversal); |
| this.parameters = new Parameters(); |
| this.ctx = new ServiceCallContext(traversal, this); |
| } |
| |
| protected Service<S, E> service() { |
| // throws exception for unrecognized service |
| return service != null ? service : (service = getServiceRegistry().get(serviceName, isStart, staticParams)); |
| } |
| |
| @Override |
| protected Traverser.Admin<E> processNextStart() { |
| if (isStart && first) { |
| first = false; |
| |
| /* |
| * Start of a traversal (no input). Obtain the one-time service iterator. |
| */ |
| |
| if (this.starts.hasNext()) { |
| throw new IllegalStateException("This service must be called without input: " + serviceName); |
| } |
| |
| this.iterator = start(); |
| } |
| |
| while (true) { |
| if (this.iterator.hasNext()) { |
| |
| /* |
| * Still draining the current iterator. |
| */ |
| |
| final Object next = this.iterator.next(); |
| if (next instanceof Traverser.Admin) { |
| /* |
| * Service is producing its own traversers (or is a pass-through on the input). Possible for |
| * streaming or barrier. |
| */ |
| return (Traverser.Admin<E>) next; |
| } else if (this.head != null) { |
| /* |
| * Streaming service mapping input (head) to non-traverser output. This applies to streaming |
| * service execution only. |
| */ |
| return this.head.split((E) next, this); |
| } else { |
| /* |
| * Barrier service producing non-traverser output, we have no head to split against. This loses |
| * all path information. |
| */ |
| return this.traversal.getTraverserGenerator().generate(next, (Step) this, 1l); |
| } |
| } else { |
| |
| /* |
| * Time to obtain another iterator from upstream input. |
| */ |
| |
| closeIterator(); |
| if (!this.starts.hasNext()) { |
| // no more input |
| throw FastNoSuchElementException.instance(); |
| } |
| if (service().isBarrier()) { |
| /* |
| * Barrier service - gather upstream input and call. |
| */ |
| final TraverserSet<S> traverserSet = (TraverserSet<S>) this.traversal.getTraverserSetSupplier().get(); |
| final int maxBarrierSize = service().getMaxBarrierSize(); |
| if (maxBarrierSize == Integer.MAX_VALUE) { |
| // all-at-once |
| this.starts.forEachRemaining(traverserSet::add); |
| } else { |
| // chunked |
| while (this.starts.hasNext() && traverserSet.size() < maxBarrierSize) { |
| traverserSet.add(this.starts.next()); |
| } |
| } |
| this.iterator = this.flatMap(traverserSet); |
| } else { |
| /* |
| * Streaming service, mark the next start and call. |
| */ |
| this.head = this.starts.next(); |
| this.iterator = this.flatMap(this.head); |
| } |
| } |
| } |
| } |
| |
| @Override |
| public void close() { |
| closeIterator(); |
| if (service != null) |
| service.close(); |
| service = null; |
| } |
| |
| protected void closeIterator() { |
| CloseableIterator.closeIterator(iterator); |
| this.iterator = EmptyCloseableIterator.instance(); |
| } |
| |
| protected Map getMergedParams() { |
| if (mapTraversal == null && parameters.isEmpty()) { |
| // static params only |
| return Collections.unmodifiableMap(this.staticParams); |
| } |
| |
| return getMergedParams(new DummyTraverser(this.traversal.getTraverserGenerator())); |
| } |
| |
| protected Map getMergedParams(final Traverser.Admin<S> traverser) { |
| if (mapTraversal == null && parameters.isEmpty()) { |
| // static params only |
| return Collections.unmodifiableMap(this.staticParams); |
| } |
| |
| // merge dynamic with static params |
| final Map params = new LinkedHashMap(this.staticParams); |
| if (mapTraversal != null) params.putAll(TraversalUtil.apply(traverser, mapTraversal)); |
| final Object[] kvs = this.parameters.getKeyValues(traverser); |
| for (int i = 0; i < kvs.length; i += 2) { |
| // this will overwrite any multi-valued kvs |
| params.put(kvs[i], kvs[i + 1]); |
| } |
| return params; |
| } |
| |
| protected Map getMergedParams(final TraverserSet<S> traverserSet) { |
| if (mapTraversal == null && parameters.isEmpty()) { |
| // static params only |
| return Collections.unmodifiableMap(this.staticParams); |
| } |
| |
| /* |
| * Dynamic params with a barrier service. We need to reduce to one set of params. For now just disallow |
| * multiple property sets. Also could be sensible to group traversers by parameter set. |
| */ |
| final Set<Map> paramsSet = new HashSet<>(); |
| for (final Traverser.Admin<S> traverser : traverserSet) { |
| paramsSet.add(getMergedParams(traverser)); |
| } |
| if (paramsSet.size() > 1) { |
| throw new UnsupportedOperationException("Cannot use multiple dynamic parameter sets with a barrier service call."); |
| } |
| return paramsSet.iterator().next(); |
| } |
| |
| protected CloseableIterator start() { |
| final Map params = getMergedParams(); |
| return service().execute(this.ctx, params); |
| } |
| |
| protected CloseableIterator flatMap(final Traverser.Admin<S> traverser) { |
| final Map params = getMergedParams(traverser); |
| return service().execute(this.ctx, traverser, params); |
| } |
| |
| protected CloseableIterator flatMap(final TraverserSet<S> traverserSet) { |
| final Map params = getMergedParams(traverserSet); |
| return service().execute(this.ctx, traverserSet, params); |
| } |
| |
| protected ServiceRegistry getServiceRegistry() { |
| final Graph graph = (Graph) this.traversal.getGraph().get(); |
| return graph.getServiceRegistry(); |
| } |
| |
| @Override |
| public void reset() { |
| super.reset(); |
| first = true; |
| if (mapTraversal != null) |
| mapTraversal.reset(); |
| parameters.getTraversals().forEach(Traversal.Admin::reset); |
| |
| closeIterator(); |
| head = null; |
| } |
| |
| @Override |
| public <S, E> List<Traversal.Admin<S, E>> getLocalChildren() { |
| final List<Traversal.Admin<S, E>> children = new ArrayList<>(); |
| if (mapTraversal != null) children.add((Traversal.Admin<S, E>) mapTraversal); |
| children.addAll(parameters.getTraversals()); |
| return children; |
| } |
| |
| @Override |
| public void setTraversal(final Traversal.Admin<?, ?> parentTraversal) { |
| super.setTraversal(parentTraversal); |
| if (mapTraversal != null) |
| this.integrateChild(mapTraversal); |
| parameters.getTraversals().forEach(this::integrateChild); |
| ctx = new ServiceCallContext(parentTraversal, this); |
| } |
| |
| @Override |
| public Set<TraverserRequirement> getRequirements() { |
| final Set<TraverserRequirement> requirements = this.getSelfAndChildRequirements(); |
| requirements.addAll(service().getRequirements()); |
| return requirements; |
| } |
| |
| @Override |
| public String toString() { |
| final ArrayList args = new ArrayList(); |
| args.add(serviceName); |
| if (!staticParams.isEmpty()) |
| args.add(staticParams); |
| if (mapTraversal != null) |
| args.add(mapTraversal); |
| if (!parameters.isEmpty()) |
| args.add(parameters); |
| return StringFactory.stepString(this, args.toArray()); |
| } |
| |
| @Override |
| public int hashCode() { |
| int hashCode = super.hashCode() ^ this.serviceName.hashCode(); |
| if (!staticParams.isEmpty()) |
| hashCode ^= staticParams.hashCode(); |
| if (mapTraversal != null) |
| hashCode ^= mapTraversal.hashCode(); |
| if (!parameters.isEmpty()) |
| hashCode ^= parameters.hashCode(); |
| return hashCode; |
| } |
| |
| @Override |
| public CallStep<S, E> clone() { |
| final CallStep<S, E> clone = (CallStep<S, E>) super.clone(); |
| clone.mapTraversal = mapTraversal != null ? mapTraversal.clone() : null; |
| clone.parameters = parameters.clone(); |
| clone.ctx = new ServiceCallContext(traversal, clone); |
| clone.iterator = EmptyCloseableIterator.instance(); |
| clone.head = null; |
| return clone; |
| } |
| |
| @Override |
| public void configure(final Object... keyValues) { |
| this.parameters.set(this, keyValues); |
| } |
| |
| @Override |
| public Parameters getParameters() { |
| return this.parameters; |
| } |
| } |