TraceWriter.java

package org.cdlib.xtf.util;


/*
 * Copyright (c) 2004, Regents of the University of California
 * 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 the University of California 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 THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER 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.
 */
import java.io.IOException;
import java.io.Writer;

/**
 * This is a simple PrintStream derivative that sends its output to the
 * XTF Trace class instead of stdout or stderr.
 */
public class TraceWriter extends Writer 
{
  /** What level to output messages at */
  private int traceLevel;

  /** Buffer to build up each line, flushed at newline */
  private StringBuffer buf = new StringBuffer();

  /**
   * Construct a TraceWriter, recording the Trace level that future
   * messages written to the stream will be output at.
   *
   * @param traceLevel  Level to output future messages.
   */
  public TraceWriter(int traceLevel) {
    this.traceLevel = traceLevel;
  } // constructor

  /** Write a series of characters. Each newline-separated line is written
   *  to the Trace stream at the configured debug level.
   */
  public void write(char[] cbuf, int off, int len)
    throws IOException 
  {
    for (int i = 0; i < len; i++) 
    {
      char c = cbuf[i + off];
      if (c == '\n') {
        output(buf.toString());
        buf.setLength(0);
      }
      else
        buf.append(c);
    }
  } // write()

  /** Output a string at the configured debug level */
  private void output(String str) 
  {
    switch (traceLevel) {
      case Trace.debug:
        Trace.debug(str);
        break;
      case Trace.info:
        Trace.info(str);
        break;
      case Trace.warnings:
        Trace.warning(str);
        break;
      case Trace.errors:
        Trace.error(str);
        break;
      default:
        assert false : "Unrecognized trace level";
    }
  } // output()

  /** Flush any remaining output in the buffer */
  public void flush()
    throws IOException 
  {
    if (buf.length() > 0) {
      output(buf.toString());
      buf.setLength(0);
    }
  } // flush()

  /** Close the stream */
  public void close()
    throws IOException 
  {
    flush();
  } // close()
} // class TraceWriter