| /* |
| * ==================================================================== |
| * 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. |
| * ==================================================================== |
| * |
| * This software consists of voluntary contributions made by many |
| * individuals on behalf of the Apache Software Foundation. For more |
| * information on the Apache Software Foundation, please see |
| * <http://www.apache.org/>. |
| * |
| */ |
| package org.apache.hc.client5.http.impl.cache; |
| |
| import java.io.Closeable; |
| import java.io.IOException; |
| import java.util.Collections; |
| import java.util.HashSet; |
| import java.util.Set; |
| import java.util.concurrent.RejectedExecutionException; |
| |
| import org.apache.hc.client5.http.cache.HttpCacheEntry; |
| import org.apache.hc.client5.http.sync.ExecChain; |
| import org.apache.hc.core5.http.ClassicHttpRequest; |
| import org.apache.hc.core5.http.HttpHost; |
| import org.apache.logging.log4j.LogManager; |
| import org.apache.logging.log4j.Logger; |
| |
| /** |
| * Class used for asynchronous revalidations to be used when the "stale- |
| * while-revalidate" directive is present |
| */ |
| class AsynchronousValidator implements Closeable { |
| private final SchedulingStrategy schedulingStrategy; |
| private final Set<String> queued; |
| private final CacheKeyGenerator cacheKeyGenerator; |
| private final FailureCache failureCache; |
| |
| private final Logger log = LogManager.getLogger(getClass()); |
| |
| /** |
| * Create AsynchronousValidator which will make revalidation requests |
| * using an {@link ImmediateSchedulingStrategy}. Its thread |
| * pool will be configured according to the given {@link CacheConfig}. |
| * @param config specifies thread pool settings. See |
| * {@link CacheConfig#getAsynchronousWorkersMax()}, |
| * {@link CacheConfig#getAsynchronousWorkersCore()}, |
| * {@link CacheConfig#getAsynchronousWorkerIdleLifetimeSecs()}, |
| * and {@link CacheConfig#getRevalidationQueueSize()}. |
| */ |
| public AsynchronousValidator(final CacheConfig config) { |
| this(new ImmediateSchedulingStrategy(config)); |
| } |
| |
| /** |
| * Create AsynchronousValidator which will make revalidation requests |
| * using the supplied {@link SchedulingStrategy}. Closing the validator |
| * will also close the given schedulingStrategy. |
| * @param schedulingStrategy used to maintain a pool of worker threads and |
| * schedules when requests are executed |
| */ |
| AsynchronousValidator(final SchedulingStrategy schedulingStrategy) { |
| this.schedulingStrategy = schedulingStrategy; |
| this.queued = new HashSet<>(); |
| this.cacheKeyGenerator = new CacheKeyGenerator(); |
| this.failureCache = new DefaultFailureCache(); |
| } |
| |
| @Override |
| public void close() throws IOException { |
| schedulingStrategy.close(); |
| } |
| |
| /** |
| * Schedules an asynchronous revalidation |
| */ |
| public synchronized void revalidateCacheEntry( |
| final CachingExec cachingExec, |
| final HttpHost target, |
| final ClassicHttpRequest request, |
| final ExecChain.Scope scope, |
| final ExecChain chain, |
| final HttpCacheEntry entry) { |
| // getVariantURI will fall back on getURI if no variants exist |
| final String uri = cacheKeyGenerator.generateVariantURI(target, request, entry); |
| |
| if (!queued.contains(uri)) { |
| final int consecutiveFailedAttempts = failureCache.getErrorCount(uri); |
| final AsynchronousValidationRequest revalidationRequest = |
| new AsynchronousValidationRequest( |
| this, cachingExec, target, request, scope, chain, entry, uri, consecutiveFailedAttempts); |
| |
| try { |
| schedulingStrategy.schedule(revalidationRequest); |
| queued.add(uri); |
| } catch (final RejectedExecutionException ree) { |
| log.debug("Revalidation for [" + uri + "] not scheduled: " + ree); |
| } |
| } |
| } |
| |
| /** |
| * Removes an identifier from the internal list of revalidation jobs in |
| * progress. This is meant to be called by |
| * {@link AsynchronousValidationRequest#run()} once the revalidation is |
| * complete, using the identifier passed in during constructions. |
| * @param identifier |
| */ |
| synchronized void markComplete(final String identifier) { |
| queued.remove(identifier); |
| } |
| |
| /** |
| * The revalidation job was successful thus the number of consecutive |
| * failed attempts will be reset to zero. Should be called by |
| * {@link AsynchronousValidationRequest#run()}. |
| * @param identifier the revalidation job's unique identifier |
| */ |
| void jobSuccessful(final String identifier) { |
| failureCache.resetErrorCount(identifier); |
| } |
| |
| /** |
| * The revalidation job did fail and thus the number of consecutive failed |
| * attempts will be increased. Should be called by |
| * {@link AsynchronousValidationRequest#run()}. |
| * @param identifier the revalidation job's unique identifier |
| */ |
| void jobFailed(final String identifier) { |
| failureCache.increaseErrorCount(identifier); |
| } |
| |
| Set<String> getScheduledIdentifiers() { |
| return Collections.unmodifiableSet(queued); |
| } |
| } |