Class MemoryHandler

public MemoryHandler()

Constructs a MemoryHandler for keeping a circular buffer of LogRecords; the initial configuration is determined by the LogManager properties described above.

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

Constructs a MemoryHandler for keeping a circular buffer of LogRecords, given some parameters. The values of the other parameters are taken from LogManager properties, as described above.

Parameters:

target - the target handler that will receive those log records that are passed on for publication.

size - the number of log records that are kept in the buffer. The value must be a at least one.

pushLevel - the push level threshold for this MemoryHandler. When a record is published whose severity level is greater than or equal to pushLevel, the push() method will be invoked in order to push the bufffer contents to target.

Throws:

IllegalArgumentException - if size is negative or zero. The GNU implementation also throws an IllegalArgumentException if target or pushLevel are null, but the API specification does not prescribe what should happen in those cases.

public void close()
            throws SecurityException

Closes this MemoryHandler and its associated target handler, discarding the contents of the memory buffer. However, any data that may have been buffered by the target Handler is forced to the underlying output device.

As soon as close has been called, a Handler should not be used anymore. Attempts to publish log records, to flush buffers, or to modify the Handler in any other way may throw runtime exceptions after calling close.

In case of an I/O failure, the ErrorManager of the associated target Handler will be informed, but the caller of this method will not receive an exception.

Overrides:

close in interface Handler

Throws:

SecurityException - if a security manager exists and the caller is not granted the permission to control the logging infrastructure.

See Also:

push()

public void flush()

Forces any data that may have been buffered by the target Handler to the underlying output device, but does not push the contents of the circular memory buffer to the target handler.

In case of an I/O failure, the ErrorManager of the target Handler will be notified, but the caller of this method will not receive an exception.

Overrides:

flush in interface Handler

See Also:

push()

public Level getPushLevel()

Returns the push level threshold for this Handler. When a record is published whose severity level is greater than or equal to the pushLevel of this MemoryHandler, the push() method will be invoked for pushing the buffer contents to the target Handler.

Returns:

the push level threshold for automatic pushing.

public void publish(LogRecord record)

Stores a LogRecord in a fixed-size circular buffer, provided the record passes all tests for being loggable. If the buffer is full, the oldest record will be discarded.

If the record has a severity level which is greater than or equal to the pushLevel of this MemoryHandler, the push() method will be invoked for pushing the buffer contents to the target Handler.

Most applications do not need to call this method directly. Instead, they will use use a Logger, which will create LogRecords and distribute them to registered handlers.

Overrides:

publish in interface Handler

Parameters:

record - the log event to be published.

public void push()

Pushes the contents of the memory buffer to the target Handler and clears the buffer. Note that the target handler will discard those records that do not satisfy its own severity level threshold, or that are not considered loggable by an installed Filter.

In case of an I/O failure, the ErrorManager of the target Handler will be notified, but the caller of this method will not receive an exception.

public void setPushLevel(Level pushLevel)

Sets the push level threshold for this Handler. When a record is published whose severity level is greater than or equal to the pushLevel of this MemoryHandler, the push() method will be invoked for pushing the buffer contents to the target Handler.

Parameters:

pushLevel - the push level threshold for automatic pushing.

Throws:

SecurityException - if a security manager exists and the caller is not granted the permission to control the logging infrastructure.

NullPointerException - if pushLevel is null.