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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 timeout, int nanos)` Causes the current thread to wait until another thread invokes the `notify()` method or the `notifyAll()` method for this object, or some other thread interrupts the current thread, or a certain amount of real time has elapsed.
`final void`	`wait(long timeout)` Causes the current thread to wait until either another thread invokes the `notify()` method or the `notifyAll()` method for this object, or a specified amount of time has elapsed.
`final void`	`wait()` Causes the current thread to wait until another thread invokes the `notify()` method or the `notifyAll()` method for this object.

Public constructors

MemoryHandler

public MemoryHandler ()

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

MemoryHandler

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

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

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

public Level getPushLevel ()

Get the pushLevel.

Returns
`Level`	the value of the `pushLevel`

isLoggable

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

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

public void push ()

Push any buffered output to the target Handler.

The buffer is then cleared.

setPushLevel

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")`.

Interfaces

Classes

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MemoryHandler

Summary

Public constructors

Public methods

Inherited methods

Public constructors

MemoryHandler

MemoryHandler

Public methods

close

flush

getPushLevel

isLoggable

publish

push

setPushLevel