/* * Copyright 1999-2005 The Apache Software Foundation. *  * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at *  *      http://www.apache.org/licenses/LICENSE-2.0 *  * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */package org.apache.log4j.spi;import java.io.Writer;import java.io.PrintWriter;import java.util.Vector;/**  * ThrowableInformation is log4j's internal representation of  * throwables. It essentially consists of a string array, called  * 'rep', where the first element, that is rep[0], represents the  * string representation of the throwable (i.e. the value you get  * when you do throwable.toString()) and subsequent elements  * correspond the stack trace with the top most entry of the stack  * corresponding to the second entry of the 'rep' array that is  * rep[1].  *  * @author Ceki G&uuml;lc&uuml;  *  * */public class ThrowableInformation implements java.io.Serializable {  static final long serialVersionUID = -4748765566864322735L;  private transient Throwable throwable;  private String[] rep;    public  ThrowableInformation(Throwable throwable) {    this.throwable = throwable;  }  public  Throwable getThrowable() {    return throwable;  }    public  String[] getThrowableStrRep() {    if(rep != null) {      return (String[]) rep.clone();    } else {      VectorWriter vw = new VectorWriter();      throwable.printStackTrace(vw);      rep = vw.toStringArray();      return rep;    }  }}/**  * VectorWriter is a seemingly trivial implemtantion of PrintWriter.  * The throwable instance that we are trying to represnt is asked to  * print itself to a VectorWriter.   *  * By our design choice, r string representation of the throwable  * does not contain any line separators. It follows that println()  * methods of VectorWriter ignore the 'ln' part.  * */class VectorWriter extends PrintWriter {      private Vector v;    VectorWriter() {    super(new NullWriter());    v = new Vector();  }  public void print(Object o) {          v.addElement(o.toString());  }    public void print(char[] chars) {    v.addElement(new String(chars));  }    public void print(String s) {    v.addElement(s);  }  public void println(Object o) {          v.addElement(o.toString());  }    // JDK 1.1.x apprenly uses this form of println while in  // printStackTrace()  public  void println(char[] chars) {    v.addElement(new String(chars));  }    public    void println(String s) {    v.addElement(s);  }  public void write(char[] chars) {    v.addElement(new String(chars));  }  public void write(char[] chars, int off, int len) {    v.addElement(new String(chars, off, len));  }  public void write(String s, int off, int len) {    v.addElement(s.substring(off, off+len));  }  public void write(String s) {     v.addElement(s);  }  public String[] toStringArray() {    int len = v.size();    String[] sa = new String[len];    for(int i = 0; i < len; i++) {      sa[i] = (String) v.elementAt(i);    }    return sa;  }}  class NullWriter extends Writer {        public void close() {    // blank  }  public void flush() {    // blank  }  public void write(char[] cbuf, int off, int len) {    // blank  }}