source: src/main/java/weka/core/Tee.java @ 24

/*
 *    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.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program; if not, write to the Free Software
 *    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

/*
 * Tee.java
 * Copyright (C) 2005 University of Waikato, Hamilton, New Zealand
 *
 */

package weka.core;

import java.io.PrintStream;
import java.util.Date;
import java.util.Vector;

/**
* This class pipelines print/println's to several PrintStreams. Useful for
* redirecting System.out and System.err to files etc.<br/>
* E.g., for redirecting stderr/stdout to files with timestamps and:<br/>
* <pre>
*    import java.io.*;
*    import weka.core.Tee;
*
*    ...
*    // stdout
*    Tee teeOut = new Tee(System.out);
*    teeOut.add(new PrintStream(new FileOutputStream("out.txt")), true);
*    System.setOut(teeOut);
*    
*    // stderr
*    Tee teeErr = new Tee(System.err);
*    teeErr.add(new PrintStream(new FileOutputStream("err.txt")), true);
*    System.setOut(teeErr);
*    ...
* </pre>
*
* @author   FracPete (fracpete at waikato dot ac dot nz)
* @version  $Revision: 5953 $
*/

public class Tee
  extends PrintStream
  implements RevisionHandler {
  
  /** the different PrintStreams. */
  protected Vector<PrintStream> m_Streams = new Vector<PrintStream>();
  
  /** whether to add timestamps or not. */
  protected Vector<Boolean> m_Timestamps = new Vector<Boolean>();
  
  /** whether to add a prefix or not. */
  protected Vector<String> m_Prefixes = new Vector<String>();
  
  /** the default printstream. */
  protected PrintStream m_Default = null;

  /**
   * initializes the object, with a default printstream.
   */
  public Tee() {
    this(null);
  }

  /**
   * initializes the object with the given default printstream, e.g.,
   * System.out.
   * 
   * @param def     the default printstream, remains also after calling clear()
   */
  public Tee(PrintStream def) {
    super(def);

    m_Default = def;
    clear();
  }

  /**
   * removes all streams and places the default printstream, if any, again in
   * the list.
   * 
   * @see #getDefault()
   */
  public void clear() {
    m_Streams.clear();
    m_Timestamps.clear();
    m_Prefixes.clear();
    
    if (getDefault() != null)
      add(getDefault());
  }

  /**
   * returns the default printstrean, can be NULL.
   * 
   * @return the default printstream
   * @see #m_Default
   */
  public PrintStream getDefault() {
    return m_Default;
  }

  /**
   * adds the given PrintStream to the list of streams, with NO timestamp and
   * NO prefix.
   * 
   * @param p       the printstream to add
   */
  public void add(PrintStream p) {
    add(p, false);
  }

  /**
   * adds the given PrintStream to the list of streams, with NO prefix.
   * 
   * @param p           the printstream to add
   * @param timestamp   whether to use timestamps or not
   */
  public void add(PrintStream p, boolean timestamp) {
    add(p, timestamp, "");
  }

  /**
   * adds the given PrintStream to the list of streams.
   * 
   * @param p           the printstream to add
   * @param timestamp   whether to use timestamps or not
   * @param prefix      the prefix to use
   */
  public void add(PrintStream p, boolean timestamp, String prefix) {
    if (m_Streams.contains(p))
      remove(p);

    // make sure it's not null
    if (prefix == null)
      prefix = "";

    m_Streams.add(p);
    m_Timestamps.add(new Boolean(timestamp));
    m_Prefixes.add(prefix);
  }

  /**
   * returns the specified PrintStream from the list.
   * 
   * @param index the index of the PrintStream to return
   * @return the specified PrintStream, or null if invalid index
   */
  public PrintStream get(int index) {
    if ( (index >= 0) && (index < size()) )
      return (PrintStream) m_Streams.get(index);
    else
      return null;
  }

  /**
   * removes the given PrintStream from the list.
   * 
   * @param p the PrintStream to remove
   * @return returns the removed PrintStream if it could be removed, null otherwise
   */
  public PrintStream remove(PrintStream p) {
    int         index;

    if (contains(p)) {
      index = m_Streams.indexOf(p);
      m_Timestamps.remove(index);
      m_Prefixes.remove(index);
      return (PrintStream) m_Streams.remove(index);
    }
    else {
      return null;
    }
  }

  /**
   * removes the given PrintStream from the list.
   * 
   * @param index the index of the PrintStream to remove
   * @return returns the removed PrintStream if it could be removed, null otherwise
   */
  public PrintStream remove(int index) {
    if ( (index >= 0) && (index < size()) ) {
      m_Timestamps.remove(index);
      m_Prefixes.remove(index);
      return (PrintStream) m_Streams.remove(index);
    }
    else {
      return null;
    }
  }

  /**
   * checks whether the given PrintStream is already in the list.
   * 
   * @param p the PrintStream to look for
   * @return true if the PrintStream is in the list
   */
  public boolean contains(PrintStream p) {
    return m_Streams.contains(p);
  }

  /**
   * returns the number of streams currently in the list.
   * 
   * @return the number of streams in the list
   */
  public int size() {
    return m_Streams.size();
  }

  /**
   * prints the prefix/timestamp (timestampe only to those streams that want
   * one).
   */
  private void printHeader() {
    for (int i = 0; i < size(); i++) {
      // prefix
      if (!((String) m_Prefixes.get(i)).equals(""))
        ((PrintStream) m_Streams.get(i)).print("[" + m_Prefixes.get(i) + "]\t");
      
      // timestamp
      if (((Boolean) m_Timestamps.get(i)).booleanValue())
        ((PrintStream) m_Streams.get(i)).print("[" + new Date() + "]\t");
    }
  }

  /**
   * flushes all the printstreams.
   */
  public void flush() {
    for (int i = 0; i < size(); i++)
      ((PrintStream) m_Streams.get(i)).flush();
  }

  /**
   * prints the given int to the streams.
   * 
   * @param x the object to print
   */
  public void print(int x) {
    printHeader();
    for (int i = 0; i < size(); i++)
      ((PrintStream) m_Streams.get(i)).print(x);
    flush();
  }

  /**
   * prints the given long to the streams.
   * 
   * @param x the object to print
   */
  public void print(long x) {
    printHeader();
    for (int i = 0; i < size(); i++)
      ((PrintStream) m_Streams.get(i)).print(x);
    flush();
  }

  /**
   * prints the given float to the streams.
   * 
   * @param x the object to print
   */
  public void print(float x) {
    printHeader();
    for (int i = 0; i < size(); i++)
      ((PrintStream) m_Streams.get(i)).print(x);
    flush();
  }

  /**
   * prints the given double to the streams.
   * 
   * @param x the object to print
   */
  public void print(double x) {
    printHeader();
    for (int i = 0; i < size(); i++)
      ((PrintStream) m_Streams.get(i)).print(x);
    flush();
  }

  /**
   * prints the given boolean to the streams.
   * 
   * @param x the object to print
   */
  public void print(boolean x) {
    printHeader();
    for (int i = 0; i < size(); i++)
      ((PrintStream) m_Streams.get(i)).print(x);
    flush();
  }

  /**
   * prints the given char to the streams.
   * 
   * @param x the object to print
   */
  public void print(char x) {
    printHeader();
    for (int i = 0; i < size(); i++)
      ((PrintStream) m_Streams.get(i)).print(x);
    flush();
  }

  /**
   * prints the given char array to the streams.
   * 
   * @param x the object to print
   */
  public void print(char[] x) {
    printHeader();
    for (int i = 0; i < size(); i++)
      ((PrintStream) m_Streams.get(i)).print(x);
    flush();
  }

  /**
   * prints the given string to the streams.
   * 
   * @param x the object to print
   */
  public void print(String x) {
    printHeader();
    for (int i = 0; i < size(); i++)
      ((PrintStream) m_Streams.get(i)).print(x);
    flush();
  }

  /**
   * prints the given object to the streams.
   * 
   * @param x the object to print
   */
  public void print(Object x) {
    printHeader();
    for (int i = 0; i < size(); i++)
      ((PrintStream) m_Streams.get(i)).print(x);
    flush();
  }

  /**
   * prints a new line to the streams.
   */
  public void println() {
    printHeader();
    for (int i = 0; i < size(); i++)
      ((PrintStream) m_Streams.get(i)).println();
    flush();
  }

  /**
   * prints the given int to the streams.
   * 
   * @param x the object to print
   */
  public void println(int x) {
    printHeader();
    for (int i = 0; i < size(); i++)
      ((PrintStream) m_Streams.get(i)).println(x);
    flush();
  }

  /**
   * prints the given long to the streams.
   * 
   * @param x the object to print
   */
  public void println(long x) {
    printHeader();
    for (int i = 0; i < size(); i++)
      ((PrintStream) m_Streams.get(i)).println(x);
    flush();
  }

  /**
   * prints the given float to the streams.
   * 
   * @param x the object to print
   */
  public void println(float x) {
    printHeader();
    for (int i = 0; i < size(); i++)
      ((PrintStream) m_Streams.get(i)).println(x);
    flush();
  }

  /**
   * prints the given double to the streams.
   * 
   * @param x the object to print
   */
  public void println(double x) {
    printHeader();
    for (int i = 0; i < size(); i++)
      ((PrintStream) m_Streams.get(i)).println(x);
    flush();
  }

  /**
   * prints the given boolean to the streams.
   * 
   * @param x the object to print
   */
  public void println(boolean x) {
    printHeader();
    for (int i = 0; i < size(); i++)
      ((PrintStream) m_Streams.get(i)).println(x);
    flush();
  }

  /**
   * prints the given char to the streams.
   * 
   * @param x the object to print
   */
  public void println(char x) {
    printHeader();
    for (int i = 0; i < size(); i++)
      ((PrintStream) m_Streams.get(i)).println(x);
    flush();
  }

  /**
   * prints the given char array to the streams.
   * 
   * @param x the object to print
   */
  public void println(char[] x) {
    printHeader();
    for (int i = 0; i < size(); i++)
      ((PrintStream) m_Streams.get(i)).println(x);
    flush();
  }

  /**
   * prints the given string to the streams.
   * 
   * @param x the object to print
   */
  public void println(String x) {
    printHeader();
    for (int i = 0; i < size(); i++)
      ((PrintStream) m_Streams.get(i)).println(x);
    flush();
  }

  /**
   * prints the given object to the streams (for Throwables we print the stack
   * trace).
   * 
   * @param x the object to print
   */
  public void println(Object x) {
    String                  line;
    Throwable               t;
    StackTraceElement[]     trace;
    int                     i;

    if (x instanceof Throwable) {
      t     = (Throwable) x;
      trace = t.getStackTrace();
      line  = t.toString() + "\n";
      for (i = 0; i < trace.length; i++)
        line += "\t" + trace[i].toString() + "\n";
      x = line;
    }

    printHeader();
    for (i = 0; i < size(); i++)
      ((PrintStream) m_Streams.get(i)).println(x);
    flush();
  }

  /**
   * Writes <code>len</code> bytes from the specified byte array starting at
   * offset <code>off</code> to this stream.  If automatic flushing is
   * enabled then the <code>flush</code> method will be invoked.
   *
   * <p> Note that the bytes will be written as given; to write characters
   * that will be translated according to the platform's default character
   * encoding, use the <code>print(char)</code> or <code>println(char)</code>
   * methods.
   *
   * @param  buf   A byte array
   * @param  off   Offset from which to start taking bytes
   * @param  len   Number of bytes to write
   */
  public void write(byte buf[], int off, int len) {
    printHeader();
    for (int i = 0; i < size(); i++)
      ((PrintStream) m_Streams.get(i)).write(buf, off, len);
    flush();
  }

  /**
   * Writes the specified byte to this stream.  If the byte is a newline and
   * automatic flushing is enabled then the <code>flush</code> method will be
   * invoked.
   *
   * <p> Note that the byte is written as given; to write a character that
   * will be translated according to the platform's default character
   * encoding, use the <code>print(char)</code> or <code>println(char)</code>
   * methods.
   *
   * @param  b  The byte to be written
   * @see #print(char)
   * @see #println(char)
   */
  public void write(int b) {
    printHeader();
    for (int i = 0; i < size(); i++)
      ((PrintStream) m_Streams.get(i)).write(b);
    flush();
  }

  /**
   * returns only the classname and the number of streams.
   * 
   * @return only the classname and the number of streams
   */
  public String toString() {
    return this.getClass().getName() + ": " + m_Streams.size();
  }
  
  /**
   * Returns the revision string.
   * 
   * @return            the revision
   */
  public String getRevision() {
    return RevisionUtils.extract("$Revision: 5953 $");
  }
}