org.apache.log4j.helpers

Class BoundedFIFO

public class BoundedFIFO extends Object

BoundedFIFO serves as the bounded first-in-first-out buffer heavily used by the {@link org.apache.log4j.AsyncAppender}.

Since: version 0.9.1

Author: Ceki Gülcü

Constructor Summary
	BoundedFIFO(int maxSize) Instantiate a new BoundedFIFO with a maximum size passed as argument.

Method Summary
LoggingEvent	get() Get the first element in the buffer.
int	getMaxSize() Get the maximum size of the buffer.
boolean	isFull() Return `true` if the buffer is full, that is, whether the number of elements in the buffer equals the buffer size.
int	length() Get the number of elements in the buffer.
void	put(LoggingEvent o) Place a {@link LoggingEvent} in the buffer.
void	resize(int newSize) Resize the buffer to a new size.
boolean	wasEmpty() Returns `true` if there is just one element in the buffer.
boolean	wasFull() Returns `true` if the number of elements in the buffer plus 1 equals the maximum buffer size, returns `false` otherwise.

Constructor Detail

BoundedFIFO

public BoundedFIFO(int maxSize)

Instantiate a new BoundedFIFO with a maximum size passed as argument.

Method Detail

get

public LoggingEvent get()

Get the first element in the buffer. Returns null if there are no elements in the buffer.

getMaxSize

public int getMaxSize()

Get the maximum size of the buffer.

isFull

public boolean isFull()

Return true if the buffer is full, that is, whether the number of elements in the buffer equals the buffer size.

length

public int length()

Get the number of elements in the buffer. This number is guaranteed to be in the range 0 to maxSize (inclusive).

put

public void put(LoggingEvent o)

Place a {@link LoggingEvent} in the buffer. If the buffer is full then the event is silently dropped. It is the caller's responsability to make sure that the buffer has free space.

resize

public void resize(int newSize)

Resize the buffer to a new size. If the new size is smaller than the old size events might be lost.

Since: 1.1

wasEmpty

public boolean wasEmpty()

Returns true if there is just one element in the buffer. In other words, if there were no elements before the last {@link #put} operation completed.

wasFull

public boolean wasFull()

Returns true if the number of elements in the buffer plus 1 equals the maximum buffer size, returns false otherwise.