gcc/libjava/classpath/javax/swing/ProgressMonitorInputStream.java

/* ProgressMonitorInputStream.java --
   Copyright (C) 2002, 2004, 2005, 2006, Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
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General Public License for more details.

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Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA.

Linking this library statically or dynamically with other modules is
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As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
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package javax.swing;

import java.awt.Component;

import java.io.FilterInputStream;
import java.io.InputStream;
import java.io.InterruptedIOException;
import java.io.IOException;

/**
 * An input stream with a {@link ProgressMonitor}.
 * 
 * @author	Andrew Selkirk
 * @author  Robert Schuster (robertschuster@fsfe.org)
 * @status updated to 1.2
 * @since 1.2
 */
public class ProgressMonitorInputStream extends FilterInputStream
{

  /**
   * The monitor watching the progress of the input stream.
   */
  private ProgressMonitor monitor;

  /**
   * read
   */
  private int read;

  /**
   * Creates a new <code>ProgressMonitorInputStream</code>.
   * 
   * @param component  the parent component for the progress monitor dialog.
   * @param message  the task description.
   * @param stream  the underlying input stream.
   */
  public ProgressMonitorInputStream(Component component, Object message,
                                    InputStream stream)
  {
    super(stream);

    int max = 0;
	
    try
      {
        max = stream.available();
      }
    catch ( IOException ioe )
      {
        // Behave like the JDK here.
      }

    monitor = new ProgressMonitor(component, message, null, 0, max);
  }

  /**
   * Resets the input stream to the point where {@link #mark(int)} was called.
   * 
   * @exception IOException TODO
   */
  public void reset() throws IOException
  {
    super.reset();

    checkMonitorCanceled();

    // TODO: The docs says the monitor should be resetted. But to which
    // value? (mark is not overridden)
  }

  /**
   * Reads an unsigned byte from the input stream and returns it as an 
   * <code>int</code> in the range of 0-255.  Returns -1 if the end of the 
   * stream has been reached.  The progress monitor is updated.
   * 
   * @return int
   * 
   * @exception IOException if there is a problem reading the stream.
   */
  public int read() throws IOException
  {
    int t = super.read();

    monitor.setProgress(++read);

    checkMonitorCanceled();

    return t;
  }

  /**
   * Reads bytes from the input stream and stores them in the supplied array,
   * and updates the progress monitor (or closes it if the end of the stream 
   * is reached).
   * 
   * @param data  the data array for returning bytes read from the stream.
   * 
   * @return The number of bytes read, or -1 if there are no more bytes in the
   *         stream.
   *         
   * @throws IOException if there is a problem reading bytes from the stream.
   */
  public int read(byte[] data) throws IOException
  {
    int t = super.read(data);

    if ( t > 0 )
      {
        read += t;
        monitor.setProgress(read);

        checkMonitorCanceled();
      }
    else
      {
        monitor.close();
      }

    return t;
  }

  /**
   * Reads up to <code>length</code> bytes from the input stream and stores 
   * them in the supplied array at the given index, and updates the progress 
   * monitor (or closes it if the end of the stream is reached).
   *
   * @param data  the data array for returning bytes read from the stream.
   * @param offset  the offset into the array where the bytes should be written. 
   * @param length  the maximum number of bytes to read from the stream.
   * 
   * @return The number of bytes read, or -1 if there are no more bytes in the
   *         stream.
   *         
   * @throws IOException if there is a problem reading bytes from the stream.
   */
  public int read(byte[] data, int offset, int length) throws IOException
  {
    int t = super.read(data, offset, length);

    if ( t > 0 )
      {
        read += t;
        monitor.setProgress(read);

        checkMonitorCanceled();
      }
    else
      {
        monitor.close();
      }

    return t;
  }

  /**
   * Skips the specified number of bytes and updates the 
   * {@link ProgressMonitor}.
   * 
   * @param length the number of bytes to skip.
   *
   * @return The actual number of bytes skipped.
   * 
   * @throws IOException if there is a problem skipping bytes in the stream.
   */
  public long skip(long length) throws IOException
  {
    long t = super.skip(length);

    // 'read' may overflow here in rare situations.
    assert ( (long) read + t <= (long) Integer.MAX_VALUE );

    read += (int) t;

    monitor.setProgress(read);

    checkMonitorCanceled();

    return t;
  }

  /**
   * Closes the input stream and the associated {@link ProgressMonitor}.
   * 
   * @throws IOException if there is a problem closing the input stream.
   */
  public void close() throws IOException
  {
    super.close();
    monitor.close();
  }

  /**
   * Returns the {@link ProgressMonitor} used by this input stream.
   * 
   * @return The progress monitor.
   */
  public ProgressMonitor getProgressMonitor()
  {
    return monitor;
  }

  private void checkMonitorCanceled() throws InterruptedIOException
  {
    if (monitor.isCanceled())
      {
        throw new InterruptedIOException("ProgressMonitor was canceled");
      }
  }

}