/*
* Copyright 2013-2014 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License").
* You may not use this file except in compliance with the License.
* A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file 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 com.amazonaws.services.s3.transfer.internal;
import java.util.concurrent.Future;
import org.apache.commons.logging.LogFactory;
import com.amazonaws.event.DeliveryMode;
import com.amazonaws.event.ProgressListener;
import com.amazonaws.event.SDKProgressPublisher;
import com.amazonaws.services.s3.transfer.PersistableTransfer;
/**
* Used to publish transfer events.
*/
public class S3ProgressPublisher extends SDKProgressPublisher {
/**
* Used to deliver a persistable transfer to the given s3 listener.
*
* @param listener only listener of type {@link S3ProgressListener} will be
* notified.
*
* @return the future of a submitted task; or null if the delivery is
* synchronous with no future task involved. Note a listener should never
* block, and therefore returning null is the typical case.
*/
public static Future<?> publishTransferPersistable(
final ProgressListener listener,
final PersistableTransfer persistableTransfer) {
if (persistableTransfer == null
|| !(listener instanceof S3ProgressListener))
return null;
final S3ProgressListener s3listener = (S3ProgressListener)listener;
return deliverEvent(s3listener, persistableTransfer);
}
private static Future<?> deliverEvent(final S3ProgressListener listener,
final PersistableTransfer persistableTransfer) {
if (SYNC) { // forces all callbacks to be made synchronously
return quietlyCallListener(listener, persistableTransfer);
}
if (!ASYNC) { // forces all callbacks to be made asynchronously
if (listener instanceof DeliveryMode) {
DeliveryMode mode = (DeliveryMode) listener;
if (mode.isSyncCallSafe()) {
// Safe to call the listener directly
return quietlyCallListener(listener, persistableTransfer);
}
}
}
// Not safe to call the listener directly; so submit an async task.
// This is unfortunate as the listener should never block in the first
// place, but such task submission is necessary to remain backward
// compatible.
return setLatestFutureTask(getExecutorService().submit(new Runnable() {
@Override public void run() {
listener.onPersistableTransfer(persistableTransfer);
}
}));
}
private static Future<?> quietlyCallListener(
final S3ProgressListener listener,
final PersistableTransfer persistableTransfer) {
try {
listener.onPersistableTransfer(persistableTransfer);
} catch(Throwable t) {
// That's right, we need to suppress all errors so as to be on par
// with the async mode where all failures will be ignored.
LogFactory.getLog(S3ProgressPublisher.class)
.debug("Failure from the event listener", t);
}
return null;
}
}