com.google.gwt.core.ext
Interface TreeLogger

public interface TreeLogger

An interface used to log messages in deferred binding generators.

Nested Class Summary

static class

TreeLogger.Type A type-safe enum of all possible logging severity types.

Field Summary

static TreeLogger.Type	ALL Logs everything -- quite a bit of stuff.
static TreeLogger.Type	DEBUG Logs detailed information that could be useful during debugging.
static TreeLogger.Type	ERROR Logs an error.
static TreeLogger.Type	INFO Logs information.
static TreeLogger	NULL A valid logger that ignores all messages.
static TreeLogger.Type	SPAM Logs extremely verbose and detailed information that is typically useful only to product implementors.
static TreeLogger.Type	TRACE Logs information related to lower-level operation.
static TreeLogger.Type	WARN Logs a warning.

Method Summary

TreeLogger	branch(TreeLogger.Type type, java.lang.String msg, java.lang.Throwable caught) Produces a branched logger, which can be used to write messages that are logically grouped together underneath the current logger.
boolean	isLoggable(TreeLogger.Type type) Determines whether or not a log entry of the specified type would actually be logged.
void	log(TreeLogger.Type type, java.lang.String msg, java.lang.Throwable caught) Logs a message and/or an exception.

Field Detail

ERROR

static final TreeLogger.Type ERROR

Logs an error.

WARN

static final TreeLogger.Type WARN

Logs a warning.

INFO

static final TreeLogger.Type INFO

Logs information.

TRACE

static final TreeLogger.Type TRACE

Logs information related to lower-level operation.

DEBUG

static final TreeLogger.Type DEBUG

Logs detailed information that could be useful during debugging.

SPAM

static final TreeLogger.Type SPAM

Logs extremely verbose and detailed information that is typically useful only to product implementors.

ALL

static final TreeLogger.Type ALL

Logs everything -- quite a bit of stuff.

NULL

static final TreeLogger NULL

A valid logger that ignores all messages. Occasionally useful when calling methods that require a logger parameter.

Method Detail

branch

TreeLogger branch(TreeLogger.Type type,
                  java.lang.String msg,
                  java.lang.Throwable caught)

Produces a branched logger, which can be used to write messages that are logically grouped together underneath the current logger. The details of how/if the resulting messages are displayed is implementation-dependent.

The log message supplied when branching serves two purposes. First, the message should be considered a heading for all the child messages below it. Second, the type of the message provides a hint as to the importance of the children below it. As an optimization, an implementation could return a "no-op" logger if messages of the specified type weren't being logged, which the implication being that all nested log messages were no more important than the level of their branch parent.

As an example of how hierarchical logging can be used, a branched logger in a GUI could write log message as child items of a parent node in a tree control. If logging to streams, such as a text console, the branched logger could prefix each entry with a unique string and indent its text so that it could be sorted later to reconstruct a proper hierarchy.

Parameters:

type -

msg - An optional message to log, which can be null if only an exception is being logged

caught - An optional exception to log, which can be null if only a message is being logged

Returns:

an instance of TreeLogger representing the new branch of the log. May be the same instance on which this method is called

isLoggable

boolean isLoggable(TreeLogger.Type type)

Determines whether or not a log entry of the specified type would actually be logged. Caller use this method to avoid constructing log messages that would be thrown away.

log

void log(TreeLogger.Type type,
         java.lang.String msg,
         java.lang.Throwable caught)

Logs a message and/or an exception. It is also legal to call this method using null arguments for both msg and caught, in which case the log event can be ignored.

Parameters:

type -

msg - An optional message to log, which can be null if only an exception is being logged

caught - An optional exception to log, which can be null if only a message is being logged