/*************************************************************************

"FreePastry" Peer-to-Peer Application Development Substrate 

Copyright 2002, Rice University. All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:

- Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.

- Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.

- Neither  the name  of Rice  University (RICE) nor  the names  of its
contributors may be  used to endorse or promote  products derived from
this software without specific prior written permission.

This software is provided by RICE and the contributors on an "as is"
basis, without any representations or warranties of any kind, express
or implied including, but not limited to, representations or
warranties of non-infringement, merchantability or fitness for a
particular purpose. In no event shall RICE or contributors be liable
for any direct, indirect, incidental, special, exemplary, or
consequential damages (including, but not limited to, procurement of
substitute goods or services; loss of use, data, or profits; or
business interruption) however caused and on any theory of liability,
whether in contract, strict liability, or tort (including negligence
or otherwise) arising in any way out of the use of this software, even
if advised of the possibility of such damage.

********************************************************************************/
package rice.environment.logging;

import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintStream;

import rice.environment.Environment;

/**
 * This class constructs an output stream that will send its output to a logger,
 * line by line. This could for example be wrapped in a PrintStream to capture
 * stdout or stderr to the log. As so: System.setOut(new PrintStream(new
 * LogOutputStream(environment, Logger.INFO, "out"), true)); System.setErr(new
 * PrintStream(new LogOutputStream(environment, Logger.INFO, "err"), true));
 *
 * @version $Id: pretty.settings 2305 2005-03-11 20:22:33Z jeffh $
 * @author jstewart
 */
public class LogOutputStream extends OutputStream {

  // the underlying logger to output to
  /**
   * DESCRIBE THE FIELD
   */
  protected Logger logger;

  // buffer where we build up output
  /**
   * DESCRIBE THE FIELD
   */
  protected byte[] buffer;

  // position where the next write into the buffer would go.
  /**
   * DESCRIBE THE FIELD
   */
  protected int offset;

  // log level to output as
  /**
   * DESCRIBE THE FIELD
   */
  protected int level;

  // size of the output buffer, in bytes
  /**
   * DESCRIBE THE FIELD
   */
  public static final int BUFFER_SIZE = 1024;

  /**
   * Constructs a LogOutputStream
   *
   * @param env - the environment to log to
   * @param level - the log level of this OutputStream's messages
   */
  public LogOutputStream(Environment env, int level) {
    this(env, level, "");
  }

  /**
   * Constructs a LogOutputStream
   *
   * @param env - the environment to log to
   * @param level - the log level of this OutputStream's messages
   * @param instance - an instance name string for disambiguation
   */
  public LogOutputStream(Environment env, int level, String instance) {
    logger = env.getLogManager().getLogger(LogOutputStream.class, instance);
    buffer = new byte[BUFFER_SIZE];
    offset = 0;
    this.level = level;
  }

  /**
   * DESCRIBE THE METHOD
   *
   * @param b DESCRIBE THE PARAMETER
   * @exception IOException DESCRIBE THE EXCEPTION
   */
  public void write(int b) throws IOException {
    if (b == '\n') {
      if ((offset > 0) && (buffer[offset - 1] == '\r')) {
        offset--;
      }
      flush();
      return;
    }
    if ((offset > 0) && buffer[offset - 1] == '\r') {
      // treat bare \r as a newline
      offset--;
      flush();
    }
    // I don't actually know why it needs to be - 1 but it works
    if (offset == buffer.length - 1) {
      flush();
    }
    // okay, so we're not unicode friendly. Cry me a river.
    buffer[offset++] = (byte) (b & 0xff);
  }

  /**
   * DESCRIBE THE METHOD
   */
  public void flush() {
    if (offset == 0) {
      return;
    }
    if (logger.level <= level) {
      logger.log(new String(buffer, 0, offset));
    }
    offset = 0;
  }

  /**
   * DESCRIBE THE METHOD
   */
  public void close() {
    flush();
  }

}
