com.googlecode.jmxtrans.util

Class OnlyOnceLogger

java.lang.Object

com.googlecode.jmxtrans.util.OnlyOnceLogger

@ThreadSafe
public class OnlyOnceLogger
extends Object

This class provides a simple filter on top of a logger to ensure that the same message is only logged once. Implementation relies on keeping the history of log messages in a HashMap. Limitations:

• to limit the memory cost, history size is limited to 32K entries by default, once this limit is reached, no more messages are sent to the logger
• 32K messages should be a reasonable limit, as long as message formats are similar they should all point to the same entry in the string cache
• log messages are compared using hashCode() and equals(), which means that those methods have better be fast on the arguments passed to the logger (probably not a problem) and that those methods have better provide a sensible meaning of equals() for our context (which is for example not the case for an array

Note: if we ever need more than just a warn() method, we should implement this class as a Proxy.

Field Summary

Fields

Modifier and Type	Field and Description
static int	DEFAULT_HISTORY_SIZE

Constructor Summary

Constructors

Constructor and Description
OnlyOnceLogger(org.slf4j.Logger logger)
OnlyOnceLogger(org.slf4j.Logger logger, int maxHistorySize)

Method Summary

Methods

Modifier and Type	Method and Description
void	infoOnce(String format, Object... arguments)

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_HISTORY_SIZE

public static final int DEFAULT_HISTORY_SIZE

See Also:

Constant Field Values

Constructor Detail

OnlyOnceLogger

public OnlyOnceLogger(org.slf4j.Logger logger)

OnlyOnceLogger

public OnlyOnceLogger(org.slf4j.Logger logger,
              int maxHistorySize)

Method Detail

infoOnce

public void infoOnce(String format,
            Object... arguments)