/*

 * Copyright (c) 1997, 1999, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package javax.swing;

import java.io.*;

import java.awt.Component;

/**

 * Monitors the progress of reading from some InputStream. This ProgressMonitor

 * is normally invoked in roughly this form:

 * <pre>

 * InputStream in = new BufferedInputStream(

 *                          new ProgressMonitorInputStream(

 *                                  parentComponent,

 *                                  "Reading " + fileName,

 *                                  new FileInputStream(fileName)));

 * </pre><p>

 * This creates a progress monitor to monitor the progress of reading

 * the input stream.  If it's taking a while, a ProgressDialog will

 * be popped up to inform the user.  If the user hits the Cancel button

 * an InterruptedIOException will be thrown on the next read.

 * All the right cleanup is done when the stream is closed.

 *

 *

 * <p>

 *

 * For further documentation and examples see

 * <a href="http://java.sun.com/docs/books/tutorial/uiswing/components/progress.html">How to Monitor Progress</a>,

 * a section in <em>The Java Tutorial.</em>

 *

 * @see ProgressMonitor

 * @see JOptionPane

 * @author James Gosling

 */

public class ProgressMonitorInputStream extends FilterInputStream

{

    private ProgressMonitor monitor;

    private int             nread = 0;

    private int             size = 0;

    /**

     * Constructs an object to monitor the progress of an input stream.

     *

     * @param message Descriptive text to be placed in the dialog box

     *                if one is popped up.

     * @param parentComponent The component triggering the operation

     *                        being monitored.

     * @param in The input stream to be monitored.

     */

    public ProgressMonitorInputStream(Component parentComponent,

                                      Object message,

                                      InputStream in) {

        super(in);

        try {

            size = in.available();

        }

        catch(IOException ioe) {

            size = 0;

        }

        monitor = new ProgressMonitor(parentComponent, message, null, 0, size);

    }

    /**

     * Get the ProgressMonitor object being used by this stream. Normally

     * this isn't needed unless you want to do something like change the

     * descriptive text partway through reading the file.

     * @return the ProgressMonitor object used by this object

     */

    public ProgressMonitor getProgressMonitor() {

        return monitor;

    }

    /**

     * Overrides <code>FilterInputStream.read</code>

     * to update the progress monitor after the read.

     */

    public int read() throws IOException {

        int c = in.read();

        if (c >= 0) monitor.setProgress(++nread);

        if (monitor.isCanceled()) {

            InterruptedIOException exc =

                                    new InterruptedIOException("progress");

            exc.bytesTransferred = nread;

            throw exc;

        }

        return c;

    }

    /**

     * Overrides <code>FilterInputStream.read</code>

     * to update the progress monitor after the read.

     */

    public int read(byte b[]) throws IOException {

        int nr = in.read(b);

        if (nr > 0) monitor.setProgress(nread += nr);

        if (monitor.isCanceled()) {

            InterruptedIOException exc =

                                    new InterruptedIOException("progress");

            exc.bytesTransferred = nread;

            throw exc;

        }

        return nr;

    }

    /**

     * Overrides <code>FilterInputStream.read</code>

     * to update the progress monitor after the read.

     */

    public int read(byte b[],

                    int off,

                    int len) throws IOException {

        int nr = in.read(b, off, len);

        if (nr > 0) monitor.setProgress(nread += nr);

        if (monitor.isCanceled()) {

            InterruptedIOException exc =

                                    new InterruptedIOException("progress");

            exc.bytesTransferred = nread;

            throw exc;

        }

        return nr;

    }

    /**

     * Overrides <code>FilterInputStream.skip</code>

     * to update the progress monitor after the skip.

     */

    public long skip(long n) throws IOException {

        long nr = in.skip(n);

        if (nr > 0) monitor.setProgress(nread += nr);

        return nr;

    }

    /**

     * Overrides <code>FilterInputStream.close</code>

     * to close the progress monitor as well as the stream.

     */

    public void close() throws IOException {

        in.close();

        monitor.close();

    }

    /**

     * Overrides <code>FilterInputStream.reset</code>

     * to reset the progress monitor as well as the stream.

     */

    public synchronized void reset() throws IOException {

        in.reset();

        nread = size - in.available();

        monitor.setProgress(nread);

    }

}