com.davidsoergel.s3napback.StreamingTransferManager.java Source code

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Here is the source code for com.davidsoergel.s3napback.StreamingTransferManager.java

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/*
 * Copyright (c) 2008-2013  David Soergel  <dev@davidsoergel.com>
 * Licensed under the Apache License, Version 2.0
 * http://www.apache.org/licenses/LICENSE-2.0
 */

package com.davidsoergel.s3napback;

import com.amazonaws.auth.AWSCredentials;
import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.AmazonS3Client;
import com.amazonaws.services.s3.model.GetObjectRequest;
import com.amazonaws.services.s3.model.S3Object;
import com.amazonaws.services.s3.transfer.Download;
import com.amazonaws.services.s3.transfer.Transfer;
import com.amazonaws.services.s3.transfer.TransferManager;
import com.amazonaws.services.s3.transfer.internal.DownloadImpl;
import com.amazonaws.services.s3.transfer.internal.DownloadMonitor;
import com.amazonaws.services.s3.transfer.internal.ProgressListenerChain;
import com.amazonaws.services.s3.transfer.internal.TransferManagerUtils;
import com.amazonaws.services.s3.transfer.internal.TransferProgressImpl;
import com.amazonaws.services.s3.transfer.internal.TransferProgressUpdatingListener;
import com.amazonaws.services.s3.transfer.internal.TransferStateChangeListener;
import com.amazonaws.util.VersionInfoUtils;

import java.io.BufferedOutputStream;
import java.util.concurrent.Callable;
import java.util.concurrent.Future;
import java.util.concurrent.ThreadPoolExecutor;

/**
 * @author <a href="mailto:dev@davidsoergel.com">David Soergel</a>
 * @version $Id$
 */
public class StreamingTransferManager extends TransferManager {
    private static final String USER_AGENT = TransferManager.class.getName() + "/" + VersionInfoUtils.getVersion();

    public StreamingTransferManager(AWSCredentials credentials) {
        this(new AmazonS3Client(credentials));
    }

    public StreamingTransferManager(AmazonS3 s3) {
        this(s3, TransferManagerUtils.createDefaultExecutorService());
    }

    private AmazonS3 s3;
    private ThreadPoolExecutor threadPool;

    public StreamingTransferManager(final AmazonS3 s3, final ThreadPoolExecutor threadPool) {
        super(s3, threadPool);
        this.s3 = s3;
        this.threadPool = threadPool;
    }

    public Download download(String bucket, String key, final BufferedOutputStream os) {
        return download(new GetObjectRequest(bucket, key), os);
    }

    public Download download(final GetObjectRequest getObjectRequest, final BufferedOutputStream os) {
        return download(getObjectRequest, os, null);
    }

    private Download download(final GetObjectRequest getObjectRequest, final BufferedOutputStream os,
            final TransferStateChangeListener stateListener) {

        appendUserAgent(getObjectRequest, USER_AGENT);

        String description = "Downloading from " + getObjectRequest.getBucketName() + "/"
                + getObjectRequest.getKey();

        // Add our own transfer progress listener
        TransferProgressImpl transferProgress = new TransferProgressImpl();
        ProgressListenerChain listenerChain = new ProgressListenerChain(
                new TransferProgressUpdatingListener(transferProgress), getObjectRequest.getProgressListener());
        getObjectRequest.setProgressListener(listenerChain);

        final S3Object s3Object = s3.getObject(getObjectRequest);
        final DownloadImpl download = new DownloadImpl(description, transferProgress, listenerChain, s3Object,
                stateListener);

        // null is returned when constraints aren't met
        if (s3Object == null) {
            download.setState(Transfer.TransferState.Canceled);
            download.setMonitor(new DownloadMonitor(download, null));
            return download;
        }

        long contentLength = s3Object.getObjectMetadata().getContentLength();
        if (getObjectRequest.getRange() != null && getObjectRequest.getRange().length == 2) {
            long startingByte = getObjectRequest.getRange()[0];
            long lastByte = getObjectRequest.getRange()[1];
            contentLength = lastByte - startingByte;
        }
        transferProgress.setTotalBytesToTransfer(contentLength);

        Future<?> future = threadPool.submit(new Callable<Object>() {
            //@Override
            public Object call() throws Exception {
                try {
                    download.setState(Transfer.TransferState.InProgress);
                    StreamingServiceUtils.downloadObjectToStream(s3Object, os);
                    download.setState(Transfer.TransferState.Completed);
                    return true;
                } catch (Exception e) {
                    // Downloads aren't allowed to move from canceled to failed
                    if (download.getState() != Transfer.TransferState.Canceled) {
                        download.setState(Transfer.TransferState.Failed);
                    }
                    throw e;
                }
            }
        });
        download.setMonitor(new DownloadMonitor(download, future));

        return download;
    }
}