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package org.apache.tomcat.util.log;
import java.io.IOException;
import java.io.PrintStream;
import java.util.Hashtable;
import java.util.Stack;
import java.util.EmptyStackException;
/**
* This helper class may be used to do sophisticated redirection of
* System.out and System.err on a per Thread basis.
*
* A stack is implemented per Thread so that nested startCapture
* and stopCapture can be used.
*
* @author Remy Maucherat
* @author Glenn L. Nielsen
*/
public class SystemLogHandler extends PrintStream {
// ----------------------------------------------------------- Constructors
/**
* Construct the handler to capture the output of the given steam.
*/
public SystemLogHandler(PrintStream wrapped) {
super(wrapped);
out = wrapped;
}
// ----------------------------------------------------- Instance Variables
/**
* Wrapped PrintStream.
*/
protected PrintStream out = null;
/**
* Thread <-> CaptureLog associations.
*/
protected static final ThreadLocal logs = new ThreadLocal();
/**
* Spare CaptureLog ready for reuse.
*/
protected static final Stack reuse = new Stack();
// --------------------------------------------------------- Public Methods
/**
* Start capturing thread's output.
*/
public static void startCapture() {
CaptureLog log = null;
if (!reuse.isEmpty()) {
try {
log = (CaptureLog)reuse.pop();
} catch (EmptyStackException e) {
log = new CaptureLog();
}
} else {
log = new CaptureLog();
}
Stack stack = (Stack)logs.get();
if (stack == null) {
stack = new Stack();
logs.set(stack);
}
stack.push(log);
}
/**
* Stop capturing thread's output and return captured data as a String.
*/
public static String stopCapture() {
Stack stack = (Stack)logs.get();
if (stack == null || stack.isEmpty()) {
return null;
}
CaptureLog log = (CaptureLog)stack.pop();
if (log == null) {
return null;
}
String capture = log.getCapture();
log.reset();
reuse.push(log);
return capture;
}
// ------------------------------------------------------ Protected Methods
/**
* Find PrintStream to which the output must be written to.
*/
protected PrintStream findStream() {
Stack stack = (Stack)logs.get();
if (stack != null && !stack.isEmpty()) {
CaptureLog log = (CaptureLog)stack.peek();
if (log != null) {
PrintStream ps = log.getStream();
if (ps != null) {
return ps;
}
}
}
return out;
}
// ---------------------------------------------------- PrintStream Methods
public void flush() {
findStream().flush();
}
public void close() {
findStream().close();
}
public boolean checkError() {
return findStream().checkError();
}
protected void setError() {
//findStream().setError();
}
public void write(int b) {
findStream().write(b);
}
public void write(byte[] b)
throws IOException {
findStream().write(b);
}
public void write(byte[] buf, int off, int len) {
findStream().write(buf, off, len);
}
public void print(boolean b) {
findStream().print(b);
}
public void print(char c) {
findStream().print(c);
}
public void print(int i) {
findStream().print(i);
}
public void print(long l) {
findStream().print(l);
}
public void print(float f) {
findStream().print(f);
}
public void print(double d) {
findStream().print(d);
}
public void print(char[] s) {
findStream().print(s);
}
public void print(String s) {
findStream().print(s);
}
public void print(Object obj) {
findStream().print(obj);
}
public void println() {
findStream().println();
}
public void println(boolean x) {
findStream().println(x);
}
public void println(char x) {
findStream().println(x);
}
public void println(int x) {
findStream().println(x);
}
public void println(long x) {
findStream().println(x);
}
public void println(float x) {
findStream().println(x);
}
public void println(double x) {
findStream().println(x);
}
public void println(char[] x) {
findStream().println(x);
}
public void println(String x) {
findStream().println(x);
}
public void println(Object x) {
findStream().println(x);
}
}