/*
* Copyright (C) The Apache Software Foundation. All rights reserved.
*
* This software is published under the terms of the Apache Software
* License version 1.1, a copy of which has been included with this
* distribution in the LICENSE.txt file. */
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 Gülcü
*
* */
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
}
}
|