/**
* Returns the current top of the thread-local logger stack or the static Logger instance scoped
* to Logger.class if the stack is empty.
*
* @return current logger [never null]
*/
public static Logger getLogger() {
final LinkedList stack = (LinkedList) THREAD_LOCAL_STACK.get();
// [assertion: stack != null]
if (stack.isEmpty()) {
return STATIC_LOGGER;
} else {
return (Logger) stack.getLast();
}
}
/**
* Requiring a context parameter here helps enforce correct push/pop nesting in the caller code.
*
* @param ctx [may not be null]
*/
public static void pop(final Logger ctx) {
// TODO: add guards for making sure only the pushing thread is allowed to
// execute this
final LinkedList stack = (LinkedList) THREAD_LOCAL_STACK.get();
try {
final Logger current = (Logger) stack.getLast();
if (current != ctx) throw new IllegalStateException("invalid context being popped: " + ctx);
stack.removeLast();
current.cleanup();
} catch (NoSuchElementException nsee) {
throw new IllegalStateException(
"empty logger context stack on thread [" + Thread.currentThread() + "]: " + nsee);
}
}
/** @param ctx [may not be null] */
public static void push(final Logger ctx) {
if (ctx == null) throw new IllegalArgumentException("null input: ctx");
final LinkedList stack = (LinkedList) THREAD_LOCAL_STACK.get();
stack.addLast(ctx);
}
