com.google.gwt.core.ext

Class TreeLogger

java.lang.Object

com.google.gwt.core.ext.TreeLogger

Direct Known Subclasses:

AbstractTreeLogger, CompositeTreeLogger

public abstract class TreeLogger
extends Object

An interface used to log messages in deferred binding generators.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	TreeLogger.HelpInfo Provides extra information to the user, generally details of what caused the problem or what the user should do to fix the problem.
static class	TreeLogger.Type A type-safe enum of all possible logging severity types.

Field Summary

Fields

Modifier and Type	Field and Description
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.

Constructor Summary

Constructors

Constructor and Description
TreeLogger()

Method Summary

Methods

Modifier and Type	Method and Description
TreeLogger	branch(TreeLogger.Type type, String msg) Calls branch(com.google.gwt.core.ext.TreeLogger.Type, String, Throwable, com.google.gwt.core.ext.TreeLogger.HelpInfo) with a null caught and helpInfo.
TreeLogger	branch(TreeLogger.Type type, String msg, Throwable caught) Calls branch(com.google.gwt.core.ext.TreeLogger.Type, String, Throwable, com.google.gwt.core.ext.TreeLogger.HelpInfo) with a null helpInfo.
abstract TreeLogger	branch(TreeLogger.Type type, String msg, Throwable caught, TreeLogger.HelpInfo helpInfo) Produces a branched logger, which can be used to write messages that are logically grouped together underneath the current logger.
abstract 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, String msg) Calls log(TreeLogger.Type, String, Throwable, HelpInfo) with a null caught and helpInfo.
void	log(TreeLogger.Type type, String msg, Throwable caught) Calls log(TreeLogger.Type, String, Throwable, HelpInfo) with a null helpInfo.
abstract void	log(TreeLogger.Type type, String msg, Throwable caught, TreeLogger.HelpInfo helpInfo) Logs a message and/or an exception, with optional help info.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

ERROR

public static final TreeLogger.Type ERROR

Logs an error.

WARN

public static final TreeLogger.Type WARN

Logs a warning.

INFO

public static final TreeLogger.Type INFO

Logs information.

TRACE

public static final TreeLogger.Type TRACE

Logs information related to lower-level operation.

DEBUG

public static final TreeLogger.Type DEBUG

Logs detailed information that could be useful during debugging.

SPAM

public static final TreeLogger.Type SPAM

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

ALL

public static final TreeLogger.Type ALL

Logs everything -- quite a bit of stuff.

NULL

public static final TreeLogger NULL

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

Constructor Detail

TreeLogger

public TreeLogger()

Method Detail

branch

public final TreeLogger branch(TreeLogger.Type type,
                String msg)

Calls branch(com.google.gwt.core.ext.TreeLogger.Type, String, Throwable, com.google.gwt.core.ext.TreeLogger.HelpInfo) with a null caught and helpInfo.

branch

public final TreeLogger branch(TreeLogger.Type type,
                String msg,
                Throwable caught)

Calls branch(com.google.gwt.core.ext.TreeLogger.Type, String, Throwable, com.google.gwt.core.ext.TreeLogger.HelpInfo) with a null helpInfo.

branch

public abstract TreeLogger branch(TreeLogger.Type type,
                String msg,
                Throwable caught,
                TreeLogger.HelpInfo helpInfo)

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

helpInfo - extra information that might be used by the logger to provide extended information to the user

Returns:

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

isLoggable

public abstract 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

public final void log(TreeLogger.Type type,
       String msg)

Calls log(TreeLogger.Type, String, Throwable, HelpInfo) with a null caught and helpInfo.

log

public final void log(TreeLogger.Type type,
       String msg,
       Throwable caught)

Calls log(TreeLogger.Type, String, Throwable, HelpInfo) with a null helpInfo.

log

public abstract void log(TreeLogger.Type type,
       String msg,
       Throwable caught,
       TreeLogger.HelpInfo helpInfo)

Logs a message and/or an exception, with optional help info. 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. The info can provide extra information to the logger; a logger may choose to ignore this info.

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

helpInfo - extra information that might be used by the logger to provide extended information to the user