org.springframework.shell.support.logging

Class DeferredLogHandler

java.lang.Object

java.util.logging.Handler

org.springframework.shell.support.logging.DeferredLogHandler

public class DeferredLogHandler
extends Handler

Defers the publication of JDK LogRecord instances until a target Handler is registered.

This class is useful if a target Handler cannot be instantiated before LogRecord instances are being published. This may be the case if the target Handler requires the establishment of complex publication infrastructure such as a GUI, message queue, IoC container and the establishment of that infrastructure may produce log messages that should ultimately be delivered to the target Handler.

In recognition that sometimes the target Handler may never be registered (perhaps due to failures configuring its supporting infrastructure), this class supports a fallback mode. When in fallback mode, a fallback Handler will receive all previous and future LogRecord instances. Fallback mode is automatically triggered if a LogRecord is published at the fallback Level. Fallback mode is also triggered if the flush() or close() method is involved and the target Handler has never been registered.

Since:

1.0

Constructor Summary

Constructors

Constructor and Description
DeferredLogHandler(Handler fallbackHandler, Level fallbackPushLevel) Creates an instance that will publish all recorded LogRecord instances to the specified fallback Handler if an event of the specified Level is received.

Method Summary

Methods

Modifier and Type	Method and Description
void	close()
void	flush()
Handler	getTargetHandler()
void	publish(LogRecord record) Stores the log record internally.
void	setTargetHandler(Handler targetHandler)

Methods inherited from class java.util.logging.Handler

getEncoding, getErrorManager, getFilter, getFormatter, getLevel, isLoggable, reportError, setEncoding, setErrorManager, setFilter, setFormatter, setLevel

Methods inherited from class java.lang.Object

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

Constructor Detail

DeferredLogHandler

public DeferredLogHandler(Handler fallbackHandler,
                  Level fallbackPushLevel)

Creates an instance that will publish all recorded LogRecord instances to the specified fallback Handler if an event of the specified Level is received.

Parameters:

fallbackHandler - to publish events to (mandatory)

fallbackPushLevel - the level which will trigger an event publication (mandatory)

Method Detail

close

public void close()
           throws SecurityException

Specified by:

close in class Handler

Throws:

SecurityException

flush

public void flush()

Specified by:

flush in class Handler

publish

public void publish(LogRecord record)

Stores the log record internally.

Specified by:

publish in class Handler

getTargetHandler

public Handler getTargetHandler()

Returns:

the target Handler, or null if there is no target Handler defined so far

setTargetHandler

public void setTargetHandler(Handler targetHandler)