org.jason.mapmaker.server.util.UploadProgressInputStream.java Source code

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Here is the source code for org.jason.mapmaker.server.util.UploadProgressInputStream.java

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/**
 * Copyright 2011 Jason Ferguson.
 *
 * 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 org.jason.mapmaker.server.util;

import org.apache.commons.fileupload.ProgressListener;

import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

/**
 * UploadProgressInputStream.java
 *
 * An InputStream that can be used to monitor file upload progress. I'll implement using this as I go.
 *
 * Based on code written by Adrian Walker:
 * http://www.adrianwalker.org/2011/03/gwt-file-upload-with-event-based.html
 *
 * @author Jason Ferguson
 */
public class UploadProgressInputStream extends FilterInputStream {

    private List<ProgressListener> listeners;
    private long bytesRead = 0;
    private long totalBytes = 0;

    public UploadProgressInputStream(final InputStream in, final long totalBytes) {
        super(in);

        this.totalBytes = totalBytes;

        listeners = new ArrayList<ProgressListener>();
    }

    public void addListener(final ProgressListener listener) {
        listeners.add(listener);
    }

    @Override
    public int read() throws IOException {
        int b = super.read();

        this.bytesRead++;

        updateListeners(bytesRead, totalBytes);

        return b;
    }

    @Override
    public int read(final byte b[]) throws IOException {
        return read(b, 0, b.length);
    }

    @Override
    public int read(final byte b[], final int off, final int len) throws IOException {
        int bytesRead = in.read(b, off, len);

        this.bytesRead = this.bytesRead + bytesRead;

        updateListeners(this.bytesRead, totalBytes);

        return bytesRead;
    }

    @Override
    public void close() throws IOException {
        super.close();

        updateListeners(totalBytes, totalBytes);
    }

    private void updateListeners(final long bytesRead, final long totalBytes) {

        for (ProgressListener listener : listeners) {

            listener.update(bytesRead, totalBytes, listeners.size());
        }
    }

}