gwtupload.server.UploadListener.java Source code

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Here is the source code for gwtupload.server.UploadListener.java

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/*
 * Copyright 2009 Manuel Carrasco Moino. (manuel_carrasco at users.sourceforge.net) 
 * http://code.google.com/p/gwtupload
 * 
 * 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://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.
 */
package gwtupload.server;

import java.util.Date;

import org.apache.commons.fileupload.ProgressListener;

public class UploadListener implements ProgressListener {

    private static final int DEFAULT_SAVE_INTERVAL = 1000;
    private final FileRepository repo;
    private final Integer fileToken;
    private Date lastSaved = new Date();
    private long lastCurrentBytes = 0;
    private int uploadDelay;

    public UploadListener(FileRepository repo, Integer fileToken, int uploadDelay) {
        this.repo = repo;
        this.fileToken = fileToken;
        this.uploadDelay = uploadDelay;
    }

    /** This method is called each time the server receives a block of bytes--could be very often. */
    public void update(long currentBytes, long totalBytes, int item) {
        // To avoid cache overloading, this object is saved when the upload starts, 
        // when it has finished, or when the interval from the last save is significant. 
        boolean save = lastCurrentBytes == 0 && currentBytes > 0 || currentBytes >= totalBytes
                || (new Date()).getTime() - lastSaved.getTime() > DEFAULT_SAVE_INTERVAL;
        lastCurrentBytes = currentBytes;
        if (!save)
            return;
        lastSaved = new Date();

        // If other request has set an exception, e.g. message=cancelled, stop so the
        // commons-fileupload's parser stops and the connection is closed.
        final FileProgress p = repo.loadProgress(fileToken);
        if (p.getMessage() != null) {
            throw new UploadCancelledException();
        }

        repo.saveProgress(fileToken, currentBytes, totalBytes);

        // Just a way to slow down the upload process and see the progress bar in fast networks.
        if (uploadDelay > 0 && currentBytes < totalBytes) {
            try {
                Thread.sleep(uploadDelay);
            } catch (InterruptedException e) {
                Thread.currentThread().interrupt();
            }
        }
    }

}