| /* |
| * 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.driver; |
| |
| import org.apache.tinkerpop.gremlin.driver.message.ResponseMessage; |
| import org.apache.tinkerpop.gremlin.process.traversal.Traversal; |
| import org.apache.tinkerpop.gremlin.process.traversal.Traverser; |
| import org.apache.tinkerpop.gremlin.process.traversal.step.util.BulkSet; |
| import org.javatuples.Pair; |
| |
| import java.util.ArrayList; |
| import java.util.Collection; |
| import java.util.Collections; |
| import java.util.HashMap; |
| import java.util.HashSet; |
| import java.util.List; |
| import java.util.Map; |
| import java.util.Queue; |
| import java.util.Set; |
| import java.util.concurrent.CompletableFuture; |
| import java.util.concurrent.ConcurrentLinkedQueue; |
| import java.util.concurrent.LinkedBlockingQueue; |
| import java.util.concurrent.atomic.AtomicReference; |
| |
| /** |
| * A queue of incoming {@link Result} objects. The queue is updated by the {@link Handler.GremlinResponseHandler} |
| * until a response terminator is identified. |
| * |
| * @author Stephen Mallette (http://stephen.genoprime.com) |
| */ |
| @SuppressWarnings("ThrowableResultOfMethodCallIgnored") |
| final class ResultQueue { |
| |
| private final LinkedBlockingQueue<Result> resultLinkedBlockingQueue; |
| |
| private Object aggregatedResult = null; |
| |
| private final AtomicReference<Throwable> error = new AtomicReference<>(); |
| |
| private final CompletableFuture<Void> readComplete; |
| |
| private final Queue<Pair<CompletableFuture<List<Result>>,Integer>> waiting = new ConcurrentLinkedQueue<>(); |
| |
| private Map<String,Object> statusAttributes = null; |
| |
| public ResultQueue(final LinkedBlockingQueue<Result> resultLinkedBlockingQueue, final CompletableFuture<Void> readComplete) { |
| this.resultLinkedBlockingQueue = resultLinkedBlockingQueue; |
| this.readComplete = readComplete; |
| } |
| |
| /** |
| * Adds a {@link Result} to the queue which will be later read by the {@link ResultSet}. |
| * |
| * @param result a return value from the {@link Traversal} or script submitted for execution |
| */ |
| public void add(final Result result) { |
| this.resultLinkedBlockingQueue.offer(result); |
| tryDrainNextWaiting(false); |
| } |
| |
| /** |
| * Adds a side-effect to the queue which may later be read by the {@link ResultSet}. Note that the side-effect |
| * is only returned when a {@link Traversal} is submitted and refers to the side-effects defined in that traversal. |
| * A "script" will not return side-effects. |
| * |
| * @param aggregateTo the value of the {@link ResponseMessage} metadata for {@link Tokens#ARGS_AGGREGATE_TO}. |
| * @param sideEffectValue the value of the side-effect itself |
| * @deprecated As of release 3.3.8, not directly replaced in the protocol as side-effect retrieval after |
| * traversal iteration is not being promoted anymore as a feature. |
| */ |
| @Deprecated |
| public void addSideEffect(final String aggregateTo, final Object sideEffectValue) { |
| switch (aggregateTo) { |
| case Tokens.VAL_AGGREGATE_TO_BULKSET: |
| if (!(sideEffectValue instanceof Traverser.Admin)) |
| throw new IllegalStateException(String.format("Side-effect value %s is a %s which does not aggregate to %s", |
| sideEffectValue, sideEffectValue.getClass().getSimpleName(), aggregateTo)); |
| |
| if (null == aggregatedResult) aggregatedResult = new BulkSet(); |
| |
| final BulkSet<Object> bs = validate(aggregateTo, BulkSet.class); |
| final Traverser.Admin traverser = (Traverser.Admin) sideEffectValue; |
| bs.add(traverser.get(), traverser.bulk()); |
| break; |
| case Tokens.VAL_AGGREGATE_TO_LIST: |
| if (null == aggregatedResult) aggregatedResult = new ArrayList(); |
| final List<Object> list = validate(aggregateTo, List.class); |
| list.add(sideEffectValue); |
| break; |
| case Tokens.VAL_AGGREGATE_TO_SET: |
| if (null == aggregatedResult) aggregatedResult = new HashSet(); |
| final Set<Object> set = validate(aggregateTo, Set.class); |
| set.add(sideEffectValue); |
| break; |
| case Tokens.VAL_AGGREGATE_TO_MAP: |
| if (!(sideEffectValue instanceof Map.Entry) && !(sideEffectValue instanceof Map)) |
| throw new IllegalStateException(String.format("Side-effect value %s is a %s which does not aggregate to %s", |
| sideEffectValue, sideEffectValue.getClass().getSimpleName(), aggregateTo)); |
| |
| // some serialization formats (e.g. graphson) may deserialize a Map.Entry to a Map with a single entry |
| if (sideEffectValue instanceof Map && ((Map) sideEffectValue).size() != 1) |
| throw new IllegalStateException(String.format("Side-effect value %s is a %s which does not aggregate to %s as it is a Map that does not have one entry", |
| sideEffectValue, sideEffectValue.getClass().getSimpleName(), aggregateTo)); |
| |
| if (null == aggregatedResult) aggregatedResult = new HashMap(); |
| |
| final Map<Object,Object > m = validate(aggregateTo, Map.class); |
| final Map.Entry entry = sideEffectValue instanceof Map.Entry ? |
| (Map.Entry) sideEffectValue : (Map.Entry) ((Map) sideEffectValue).entrySet().iterator().next(); |
| m.put(entry.getKey(), entry.getValue()); |
| break; |
| case Tokens.VAL_AGGREGATE_TO_NONE: |
| if (null == aggregatedResult) aggregatedResult = sideEffectValue; |
| break; |
| default: |
| throw new IllegalStateException(String.format("%s is an invalid value for %s", aggregateTo, Tokens.ARGS_AGGREGATE_TO)); |
| } |
| } |
| |
| private <V> V validate(final String aggregateTo, final Class<?> expected) { |
| if (!(expected.isAssignableFrom(aggregatedResult.getClass()))) |
| throw new IllegalStateException(String.format("Side-effect \"%s\" contains the type %s that is not acceptable for %s", |
| aggregatedResult.getClass().getSimpleName(), aggregateTo)); |
| |
| return (V) aggregatedResult; |
| } |
| |
| public CompletableFuture<List<Result>> await(final int items) { |
| final CompletableFuture<List<Result>> result = new CompletableFuture<>(); |
| waiting.add(Pair.with(result, items)); |
| |
| tryDrainNextWaiting(false); |
| |
| return result; |
| } |
| |
| public int size() { |
| if (error.get() != null) throw new RuntimeException(error.get()); |
| return this.resultLinkedBlockingQueue.size(); |
| } |
| |
| public boolean isEmpty() { |
| if (error.get() != null) throw new RuntimeException(error.get()); |
| return this.size() == 0; |
| } |
| |
| public boolean isComplete() { |
| return readComplete.isDone(); |
| } |
| |
| void drainTo(final Collection<Result> collection) { |
| if (error.get() != null) throw new RuntimeException(error.get()); |
| resultLinkedBlockingQueue.drainTo(collection); |
| } |
| |
| void markComplete(final Map<String,Object> statusAttributes) { |
| // if there was some aggregation performed in the queue then the full object is hanging out waiting to be |
| // added to the ResultSet |
| if (aggregatedResult != null) |
| add(new Result(aggregatedResult)); |
| |
| this.statusAttributes = null == statusAttributes ? Collections.emptyMap() : statusAttributes; |
| |
| this.readComplete.complete(null); |
| |
| this.drainAllWaiting(); |
| } |
| |
| void markError(final Throwable throwable) { |
| error.set(throwable); |
| this.readComplete.completeExceptionally(throwable); |
| this.drainAllWaiting(); |
| } |
| |
| Map<String,Object> getStatusAttributes() { |
| return statusAttributes; |
| } |
| |
| /** |
| * Completes the next waiting future if there is one. |
| */ |
| private synchronized void tryDrainNextWaiting(final boolean force) { |
| // need to peek because the number of available items needs to be >= the expected size for that future. if not |
| // it needs to keep waiting |
| final Pair<CompletableFuture<List<Result>>, Integer> nextWaiting = waiting.peek(); |
| if (nextWaiting != null && (force || (resultLinkedBlockingQueue.size() >= nextWaiting.getValue1() || readComplete.isDone()))) { |
| final int items = nextWaiting.getValue1(); |
| final CompletableFuture<List<Result>> future = nextWaiting.getValue0(); |
| final List<Result> results = new ArrayList<>(items); |
| resultLinkedBlockingQueue.drainTo(results, items); |
| |
| // it's important to check for error here because a future may have already been queued in "waiting" prior |
| // to the first response back from the server. if that happens, any "waiting" futures should be completed |
| // exceptionally otherwise it will look like success. |
| if (null == error.get()) |
| future.complete(results); |
| else |
| future.completeExceptionally(error.get()); |
| |
| waiting.remove(nextWaiting); |
| } |
| } |
| |
| /** |
| * Completes all remaining futures. |
| */ |
| private void drainAllWaiting() { |
| while (!waiting.isEmpty()) { |
| tryDrainNextWaiting(true); |
| } |
| } |
| } |