Added in API level 1

Summary: Ctors | Methods | Inherited Methods

MemoryHandler

public class MemoryHandler
extends Handler

java.lang.Object
↳	java.util.logging.Handler
	↳	java.util.logging.MemoryHandler

---

Handler that buffers requests in a circular buffer in memory.

Normally this Handler simply stores incoming LogRecords into its memory buffer and discards earlier records. This buffering is very cheap and avoids formatting costs. On certain trigger conditions, the MemoryHandler will push out its current buffer contents to a target Handler, which will typically publish them to the outside world.

There are three main models for triggering a push of the buffer:

• An incoming LogRecord has a type that is greater than a pre-defined level, the pushLevel.
• An external class calls the push method explicitly.
• A subclass overrides the log method and scans each incoming LogRecord and calls push if a record matches some desired criteria.

Configuration: By default each MemoryHandler is initialized using the following LogManager configuration properties where <handler-name> refers to the fully-qualified class name of the handler. If properties are not defined (or have invalid values) then the specified default values are used. If no default value is defined then a RuntimeException is thrown.

• <handler-name>.level specifies the level for the Handler (defaults to Level.ALL).
• <handler-name>.filter specifies the name of a Filter class to use (defaults to no Filter).
• <handler-name>.size defines the buffer size (defaults to 1000).
• <handler-name>.push defines the pushLevel (defaults to level.SEVERE).
• <handler-name>.target specifies the name of the target Handler class. (no default).

For example, the properties for MemoryHandler would be:

• java.util.logging.MemoryHandler.level=INFO
• java.util.logging.MemoryHandler.formatter=java.util.logging.SimpleFormatter

For a custom handler, e.g. com.foo.MyHandler, the properties would be:

• com.foo.MyHandler.level=INFO
• com.foo.MyHandler.formatter=java.util.logging.SimpleFormatter

Summary

Public constructors
MemoryHandler() Create a MemoryHandler and configure it based on LogManager configuration properties.
MemoryHandler(Handler target, int size, Level pushLevel) Create a MemoryHandler.

Public methods
void	close() Close the Handler and free all associated resources.
void	flush() Causes a flush on the target Handler.
Level	getPushLevel() Get the pushLevel.
boolean	isLoggable(LogRecord record) Check if this Handler would actually log a given LogRecord into its internal buffer.
void	publish(LogRecord record) Store a LogRecord in an internal buffer.
void	push() Push any buffered output to the target Handler.
void	setPushLevel(Level newLevel) Set the pushLevel.

Inherited methods
From class java.util.logging.Handler abstract void close() Close the Handler and free all associated resources. abstract void flush() Flush any buffered output. String getEncoding() Return the character encoding for this Handler. ErrorManager getErrorManager() Retrieves the ErrorManager for this Handler. Filter getFilter() Get the current Filter for this Handler. Formatter getFormatter() Return the Formatter for this Handler. Level getLevel() Get the log level specifying which messages will be logged by this Handler. boolean isLoggable(LogRecord record) Check if this Handler would actually log a given LogRecord. abstract void publish(LogRecord record) Publish a LogRecord. void reportError(String msg, Exception ex, int code) Protected convenience method to report an error to this Handler's ErrorManager. void setEncoding(String encoding) Set the character encoding used by this Handler. void setErrorManager(ErrorManager em) Define an ErrorManager for this Handler. void setFilter(Filter newFilter) Set a Filter to control output on this Handler. void setFormatter(Formatter newFormatter) Set a Formatter. void setLevel(Level newLevel) Set the log level specifying which message levels will be logged by this Handler.
From class java.lang.Object Object clone() Creates and returns a copy of this object. boolean equals(Object obj) Indicates whether some other object is "equal to" this one. void finalize() Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. final Class<?> getClass() Returns the runtime class of this Object. int hashCode() Returns a hash code value for the object. final void notify() Wakes up a single thread that is waiting on this object's monitor. final void notifyAll() Wakes up all threads that are waiting on this object's monitor. String toString() Returns a string representation of the object. final void wait(long timeoutMillis, int nanos) Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed. final void wait(long timeoutMillis) Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed. final void wait() Causes the current thread to wait until it is awakened, typically by being notified or interrupted.

Public constructors

MemoryHandler

Added in API level 1

public MemoryHandler ()

Create a MemoryHandler and configure it based on LogManager configuration properties.

MemoryHandler

Added in API level 1

public MemoryHandler (Handler target, 
                int size, 
                Level pushLevel)

Create a MemoryHandler.

The MemoryHandler is configured based on LogManager properties (or their default values) except that the given pushLevel argument and buffer size argument are used.

Parameters
target	Handler: the Handler to which to publish output.
size	int: the number of log records to buffer (must be greater than zero)
pushLevel	Level: message level to push on

Throws
IllegalArgumentException	if size is <= 0

Public methods

close

Added in API level 1

public void close ()

Close the Handler and free all associated resources. This will also close the target Handler.

Throws
SecurityException	if a security manager exists and if the caller does not have LoggingPermission("control").

flush

Added in API level 1

public void flush ()

Causes a flush on the target Handler.

Note that the current contents of the MemoryHandler buffer are not written out. That requires a "push".

getPushLevel

Added in API level 1

public Level getPushLevel ()

Get the pushLevel.

Returns
Level	the value of the pushLevel

isLoggable

Added in API level 1

public boolean isLoggable (LogRecord record)

Check if this Handler would actually log a given LogRecord into its internal buffer.

This method checks if the LogRecord has an appropriate level and whether it satisfies any Filter. However it does not check whether the LogRecord would result in a "push" of the buffer contents. It will return false if the LogRecord is null.

Parameters
record	LogRecord: a LogRecord

Returns
boolean	true if the LogRecord would be logged.

publish

Added in API level 1

public void publish (LogRecord record)

Store a LogRecord in an internal buffer.

If there is a Filter, its isLoggable method is called to check if the given log record is loggable. If not we return. Otherwise the given record is copied into an internal circular buffer. Then the record's level property is compared with the pushLevel. If the given level is greater than or equal to the pushLevel then push is called to write all buffered records to the target output Handler.

Parameters
record	LogRecord: description of the log event. A null record is silently ignored and is not published

push

Added in API level 1

public void push ()

Push any buffered output to the target Handler.

The buffer is then cleared.

setPushLevel

Added in API level 1

public void setPushLevel (Level newLevel)

Set the pushLevel. After a LogRecord is copied into our internal buffer, if its level is greater than or equal to the pushLevel, then push will be called.

Parameters
newLevel	Level: the new value of the pushLevel

Throws
SecurityException	if a security manager exists and if the caller does not have LoggingPermission("control").