src/org/objectweb/cjdbc/common/util/LoggingOutputStream.java

説明を見る。

package org.objectweb.cjdbc.common.util;

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

import org.apache.log4j.Category;
import org.apache.log4j.Priority;

public class LoggingOutputStream extends OutputStream
{
  protected static final String LINE_SEPERATOR        = System
                                                          .getProperty("line.separator");
  protected boolean             hasBeenClosed         = false;
  protected byte[]              buf;
  protected int                 count;
  private int                   bufLength;
  public static final int       DEFAULT_BUFFER_LENGTH = 2048;
  protected Category            category;
  protected Priority            priority;

  private LoggingOutputStream()
  {
    // illegal
  }

  public LoggingOutputStream(Category cat, Priority priority)
      throws IllegalArgumentException
  {
    if (cat == null)
    {
      throw new IllegalArgumentException("cat == null");
    }
    if (priority == null)
    {
      throw new IllegalArgumentException("priority == null");
    }
    this.priority = priority;
    category = cat;
    bufLength = DEFAULT_BUFFER_LENGTH;
    buf = new byte[DEFAULT_BUFFER_LENGTH];
    count = 0;
  }

  public void close()
  {
    flush();
    hasBeenClosed = true;
  }

  public void write(final int b) throws IOException
  {
    if (hasBeenClosed)
    {
      throw new IOException("The stream has been closed.");
    }
    // don't log nulls
    if (b == 0)
    {
      return;
    }
    // would this be writing past the buffer?
    if (count == bufLength)
    {
      // grow the buffer
      final int newBufLength = bufLength + DEFAULT_BUFFER_LENGTH;
      final byte[] newBuf = new byte[newBufLength];
      System.arraycopy(buf, 0, newBuf, 0, bufLength);
      buf = newBuf;
      bufLength = newBufLength;
    }
    buf[count] = (byte) b;
    count++;
  }

  public void flush()
  {
    if (count == 0)
    {
      return;
    }
    // don't print out blank lines; flushing from PrintStream puts out these
    if (count == LINE_SEPERATOR.length())
    {
      if (((char) buf[0]) == LINE_SEPERATOR.charAt(0) && ((count == 1) || // <-
                                                                                                                                 // Unix
                                                                                                                                 // &
                                                                                                                                 // Mac,
                                                                                                                                 // ->
                                                                                                                                 // Windows
          ((count == 2) && ((char) buf[1]) == LINE_SEPERATOR.charAt(1))))
      {
        reset();
        return;
      }
    }
    final byte[] theBytes = new byte[count];
    System.arraycopy(buf, 0, theBytes, 0, count);
    
    // ADDED: We don't want blank lines at all
    String bytes  = new String(theBytes).trim();
    int line = -1;
    while((line = bytes.indexOf(LINE_SEPERATOR))!=-1)
    {
        bytes = bytes.substring(0, line) + bytes.substring(line+LINE_SEPERATOR.length());
    }
    // END ADDED 
    
    category.log(priority, bytes);
    reset();
  }

  private void reset()
  {
    // not resetting the buffer -- assuming that if it grew that it
    //   will likely grow similarly again
    count = 0;
  }
}

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