Java tutorial
/* * Copyright 2011-2013 Amazon Technologies, Inc. * * Licensed 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://aws.amazon.com/apache2.0 * * 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 pt.lunacloud.services.storage.transfer.internal; import java.util.ArrayList; import java.util.List; import java.util.concurrent.Callable; import java.util.concurrent.CancellationException; import java.util.concurrent.ExecutorService; import java.util.concurrent.Future; import java.util.concurrent.ScheduledExecutorService; import java.util.concurrent.TimeUnit; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import pt.lunacloud.LunacloudClientException; import pt.lunacloud.services.storage.LunacloudStorage; import pt.lunacloud.services.storage.model.CompleteMultipartUploadRequest; import pt.lunacloud.services.storage.model.CompleteMultipartUploadResult; import pt.lunacloud.services.storage.model.PartETag; import pt.lunacloud.services.storage.model.ProgressEvent; import pt.lunacloud.services.storage.model.PutObjectRequest; import pt.lunacloud.services.storage.transfer.TransferManager; import pt.lunacloud.services.storage.transfer.TransferManagerConfiguration; import pt.lunacloud.services.storage.transfer.Transfer.TransferState; import pt.lunacloud.services.storage.transfer.model.UploadResult; /** * Manages an upload by periodically checking to see if the upload is done, and * returning a result if so. Otherwise, schedules a copy of itself to be run in * the future and returns null. When waiting on the result of this class via a * Future object, clients must call {@link UploadMonitor#isDone()} and * {@link UploadMonitor#getFuture()} */ public class UploadMonitor implements Callable<UploadResult>, TransferMonitor { private final LunacloudStorage s3; private final ExecutorService threadPool; private final PutObjectRequest putObjectRequest; private ScheduledExecutorService timedThreadPool; private static final Log log = LogFactory.getLog(UploadMonitor.class); private final TransferManagerConfiguration configuration; private final ProgressListenerChain progressListenerChain; private final UploadCallable multipartUploadCallable; private final UploadImpl transfer; /* * State for tracking the upload's progress */ private String uploadId; private final List<Future<PartETag>> futures = new ArrayList<Future<PartETag>>(); /* * State for clients wishing to poll for completion */ private boolean isUploadDone = false; private Future<UploadResult> nextFuture; public synchronized Future<UploadResult> getFuture() { return nextFuture; } private synchronized void setNextFuture(Future<UploadResult> nextFuture) { this.nextFuture = nextFuture; } public synchronized boolean isDone() { return isUploadDone; } private synchronized void markAllDone() { isUploadDone = true; } // TODO: this could be configured in the configuration object (which we're // not using right now) private int pollInterval = 5000; /** * Constructs a new upload watcher, which immediately submits itself to the * thread pool. * * @param manager * The {@link TransferManager} that owns this upload. * @param transfer * The transfer being processed. * @param threadPool * The {@link ExecutorService} to which we should submit new * tasks. * @param multipartUploadCallable * The callable responsible for processing the upload * asynchronously * @param putObjectRequest * The original putObject request * @param progressListenerChain * A chain of listeners that wish to be notified of upload * progress */ public UploadMonitor(TransferManager manager, UploadImpl transfer, ExecutorService threadPool, UploadCallable multipartUploadCallable, PutObjectRequest putObjectRequest, ProgressListenerChain progressListenerChain) { this.s3 = manager.getAmazonS3Client(); this.configuration = manager.getConfiguration(); this.multipartUploadCallable = multipartUploadCallable; this.threadPool = threadPool; this.putObjectRequest = putObjectRequest; this.progressListenerChain = progressListenerChain; this.transfer = transfer; setNextFuture(threadPool.submit(this)); } public void setTimedThreadPool(ScheduledExecutorService timedThreadPool) { this.timedThreadPool = timedThreadPool; } public UploadResult call() throws Exception { try { if (uploadId == null) { return upload(); } else { return poll(); } } catch (CancellationException e) { transfer.setState(TransferState.Canceled); fireProgressEvent(ProgressEvent.CANCELED_EVENT_CODE); throw new LunacloudClientException("Upload canceled"); } catch (Exception e) { transfer.setState(TransferState.Failed); fireProgressEvent(ProgressEvent.FAILED_EVENT_CODE); throw e; } } /** * Polls for a result from a multipart upload and either returns it if * complete, or reschedules to poll again later if not. */ private UploadResult poll() throws InterruptedException { for (Future<PartETag> f : futures) { if (!f.isDone()) { reschedule(); return null; } } for (Future<PartETag> f : futures) { if (f.isCancelled()) { throw new CancellationException(); } } return completeMultipartUpload(); } /** * Initiates the upload and checks on the result. If it has completed, * returns the result; otherwise, reschedules to check back later. */ private UploadResult upload() throws Exception, InterruptedException { UploadResult result = multipartUploadCallable.call(); if (result != null) { uploadComplete(); } else { uploadId = multipartUploadCallable.getMultipartUploadId(); futures.addAll(multipartUploadCallable.getFutures()); reschedule(); } return result; } private void uploadComplete() { markAllDone(); transfer.setState(TransferState.Completed); // AmazonS3Client takes care of all the events for single part uploads, // so we only need to send a completed event for multipart uploads. if (multipartUploadCallable.isMultipartUpload()) { fireProgressEvent(ProgressEvent.COMPLETED_EVENT_CODE); } } private void reschedule() { setNextFuture(timedThreadPool.schedule(new Callable<UploadResult>() { public UploadResult call() throws Exception { setNextFuture(threadPool.submit(UploadMonitor.this)); return null; } }, pollInterval, TimeUnit.MILLISECONDS)); } private void fireProgressEvent(int eventType) { if (progressListenerChain == null) return; ProgressEvent event = new ProgressEvent(0); event.setEventCode(eventType); progressListenerChain.progressChanged(event); } /** * Completes the multipart upload and returns the result. */ private UploadResult completeMultipartUpload() { CompleteMultipartUploadResult completeMultipartUploadResult = s3 .completeMultipartUpload(new CompleteMultipartUploadRequest(putObjectRequest.getBucketName(), putObjectRequest.getKey(), uploadId, collectPartETags())); uploadComplete(); UploadResult uploadResult = new UploadResult(); uploadResult.setBucketName(completeMultipartUploadResult.getBucketName()); uploadResult.setKey(completeMultipartUploadResult.getKey()); uploadResult.setETag(completeMultipartUploadResult.getETag()); uploadResult.setVersionId(completeMultipartUploadResult.getVersionId()); return uploadResult; } private List<PartETag> collectPartETags() { final List<PartETag> partETags = new ArrayList<PartETag>(futures.size()); for (Future<PartETag> future : futures) { try { partETags.add(future.get()); } catch (Exception e) { throw new LunacloudClientException("Unable to upload part: " + e.getCause().getMessage(), e.getCause()); } } return partETags; } }