## 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