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/*
* ====================================================================
* 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 ch.boye.httpclientandroidlib.impl.client.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 ch.boye.httpclientandroidlib.androidextra.HttpClientAndroidLog;
/* LogFactory removed by HttpClient for Android script. */
import ch.boye.httpclientandroidlib.client.cache.HttpCacheEntry;
import ch.boye.httpclientandroidlib.client.methods.HttpExecutionAware;
import ch.boye.httpclientandroidlib.client.methods.HttpRequestWrapper;
import ch.boye.httpclientandroidlib.client.protocol.HttpClientContext;
import ch.boye.httpclientandroidlib.conn.routing.HttpRoute;
/**
* 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;
public HttpClientAndroidLog log = new HttpClientAndroidLog(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<String>();
this.cacheKeyGenerator = new CacheKeyGenerator();
this.failureCache = new DefaultFailureCache();
}
public void close() throws IOException {
schedulingStrategy.close();
}
/**
* Schedules an asynchronous revalidation
*/
public synchronized void revalidateCacheEntry(
final CachingExec cachingExec,
final HttpRoute route,
final HttpRequestWrapper request,
final HttpClientContext context,
final HttpExecutionAware execAware,
final HttpCacheEntry entry) {
// getVariantURI will fall back on getURI if no variants exist
final String uri = cacheKeyGenerator.getVariantURI(context.getTargetHost(), request, entry);
if (!queued.contains(uri)) {
final int consecutiveFailedAttempts = failureCache.getErrorCount(uri);
final AsynchronousValidationRequest revalidationRequest =
new AsynchronousValidationRequest(
this, cachingExec, route, request, context, execAware, 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);
}
}
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