Source Code : Size Limit InputStream

Java Is Open Source Programming Language You Can Download From Java and Java Libraries From http://www.oracle.com. Click Here to download
We provide this code related to title for you to solve your developing problem easily. Libraries which is import in this program you can download from http://www.oracle.com. Click Here or search from google with Libraries Name you get jar file related it

Size Limit InputStream

    
/*
 * Input stream wrapper with a byte limit.
 * Copyright (C) 2004 Stephen Ostermiller
 * http://ostermiller.org/contact.pl?regarding=Java+Utilities
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 for more details.
 *
 * See COPYING.TXT for details.
 */

import java.io.*;

/**
 * An input stream wrapper that will read only a set number of bytes from the
 * underlying stream.
 *
 * @author Stephen Ostermiller http://ostermiller.org/contact.pl?regarding=Java+Utilities
 * @since ostermillerutils 1.04.00
 */
public class SizeLimitInputStream extends InputStream {

  /**
   * The input stream that is being protected.
   * All methods should be forwarded to it,
   * after checking the size that has been read.
   *
   * @since ostermillerutils 1.04.00
   */
  protected InputStream in;

  /**
   * The number of bytes to read at most from this
   * Stream.  Read methods should
   * check to ensure that bytesRead never
   * exceeds maxBytesToRead.
   *
   * @since ostermillerutils 1.04.00
   */
  protected long maxBytesToRead = 0;

  /**
   * The number of bytes that have been read
   * from this stream.  Read methods should
   * check to ensure that bytesRead never
   * exceeds maxBytesToRead.
   *
   * @since ostermillerutils 1.04.00
   */
  protected long bytesRead = 0;

  /**
   * The number of bytes that have been read
   * from this stream since mark() was called.
   *
   * @since ostermillerutils 1.04.00
   */
  protected long bytesReadSinceMark = 0;

  /**
   * The number of bytes the user has request
   * to have been marked for reset.
   *
   * @since ostermillerutils 1.04.00
   */
  protected long markReadLimitBytes = -1;

  /**
   * Get the number of bytes actually read
   * from this stream.
   *
   * @return number of bytes that have already been taken from this stream.
   *
   * @since ostermillerutils 1.04.00
   */
  public long getBytesRead(){
    return bytesRead;
  }

  /**
   * Get the maximum number of bytes left to read
   * before the limit (set in the constructor) is reached.
   *
   * @return The number of bytes that (at a maximum) are left to be taken from this stream.
   *
   * @since ostermillerutils 1.04.00
   */
  public long getBytesLeft(){
    return maxBytesToRead - bytesRead;
  }

  /**
   * Tell whether the number of bytes specified
   * in the constructor have been read yet.
   *
   * @return true iff the specified number of bytes have all been read.
   *
   * @since ostermillerutils 1.04.00
   */
  public boolean allBytesRead(){
    return getBytesLeft() == 0;
  }

  /**
   * Get the number of total bytes (including bytes already read)
   * that can be read from this stream (as set in the constructor).
   * @return Maximum bytes that can be read until the size limit runs out
   *
   * @since ostermillerutils 1.04.00
   */
  public long getMaxBytesToRead(){
    return maxBytesToRead;
  }

  /**
   * Create a new size limit input stream from
   * another stream given a size limit.
   *
   * @param in The input stream.
   * @param maxBytesToRead the max number of bytes to allow to be read from the underlying stream.
   *
   * @since ostermillerutils 1.04.00
   */
  public SizeLimitInputStream(InputStream in, long maxBytesToRead){
    this.in = in;
    this.maxBytesToRead = maxBytesToRead;
  }

  /**
   * {@inheritDoc}
   */
  @Override public int read() throws IOException {
    if (bytesRead >= maxBytesToRead){
      return -1;
    }
    int b = in.read();
    if(b != -1){
      bytesRead++;
      bytesReadSinceMark++;
    }
    return b;
  }

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

  /**
   * {@inheritDoc}
   */
  @Override public int read(byte[] b, int off, int len) throws IOException {
    if (bytesRead >= maxBytesToRead){
      return -1;
    }
    long bytesLeft = getBytesLeft();
    if (len > bytesLeft){
      len = (int)bytesLeft;
    }
    int bytesJustRead = in.read(b, off, len);
    bytesRead += bytesJustRead;
    bytesReadSinceMark += bytesJustRead;
    return bytesJustRead;
  }

  /**
   * {@inheritDoc}
   */
  @Override public long skip(long n) throws IOException {
    if (bytesRead >= maxBytesToRead){
      return -1;
    }
    long bytesLeft = getBytesLeft();
    if (n > bytesLeft){
      n = bytesLeft;
    }
    return in.skip(n);
  }

  /**
   * {@inheritDoc}
   */
  @Override public int available() throws IOException {
    int available = in.available();
    long bytesLeft = getBytesLeft();
    if (available > bytesLeft){
      available = (int)bytesLeft;
    }
    return available;
  }

  /**
   * Close this stream and underlying streams.
   * Calling this method may make data on the
   * underlying stream unavailable.
   * <p>
   * Consider wrapping this stream in a NoCloseStream
   * so that clients can
   * call close() with no effect.
   *
   * @since ostermillerutils 1.04.00
   */
  @Override public void close() throws IOException {
    in.close();
  }

  /**
   * {@inheritDoc}
   */
  @Override public void mark(int readlimit){
    if (in.markSupported()){
      markReadLimitBytes = readlimit;
      bytesReadSinceMark = 0;
      in.mark(readlimit);
    }
  }

  /**
   * {@inheritDoc}
   */
  @Override public void reset() throws IOException {
    if (in.markSupported() && bytesReadSinceMark <= markReadLimitBytes){
      bytesRead -= bytesReadSinceMark;
      in.reset();
      bytesReadSinceMark = 0;
    }
  }

  /**
   * {@inheritDoc}
   */
  @Override public boolean markSupported(){
    return in.markSupported();
  }
}

   
    
    
    
  

Thank with us