cmsc433.p1
Class NullLog

java.lang.Object
  cmsc433.p1.NullLog

All Implemented Interfaces:

Log

public class NullLog
extends java.lang.Object
implements Log

A Log that discards all elements added to it. However, listeners should be notified when the add method is called. This class should be thread-safe.

Constructor Summary

NullLog()

Method Summary

void	add(LogRecord l) Stores a LogRecord in the Log.
java.util.List<LogRecord>	flush() Returns all LogRecords kept in the log, emptying the log.
java.util.List<LogRecord>	getAll(long windowMS) Returns all LogRecords whose timestamps are within a window of time.
void	register(Listener<LogRecord> l) Registers a listener that whose notify() method will be called whenever a record is added to this log; the first argument of notify() is the log itself, and the second is the LogRecord that was added.
java.lang.String	toString()
void	unregister(Listener<LogRecord> l) Removes a previously-registered listener.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

NullLog

public NullLog()

Method Detail

add

public void add(LogRecord l)

Description copied from interface: Log

Stores a LogRecord in the Log. Implementations may choose to only add some logs (e.g. logs matching a given pattern).

Specified by:

add in interface Log

getAll

public java.util.List<LogRecord> getAll(long windowMS)

Description copied from interface: Log

Returns all LogRecords whose timestamps are within a window of time. Note that inclusion is based on the timestamp of the LogRecord, not the time at which the record was stored in the Log. This is non-destructive; all records remain in the Log.

Specified by:

getAll in interface Log

Parameters:

windowMS - return all records from the last [windowMS] milliseconds.

flush

public java.util.List<LogRecord> flush()

Description copied from interface: Log

Returns all LogRecords kept in the log, emptying the log.

Specified by:

flush in interface Log

register

public void register(Listener<LogRecord> l)

Description copied from interface: Log

Registers a listener that whose notify() method will be called whenever a record is added to this log; the first argument of notify() is the log itself, and the second is the LogRecord that was added.

Specified by:

register in interface Log

Parameters:

l - The listener to register.

unregister

public void unregister(Listener<LogRecord> l)

Description copied from interface: Log

Removes a previously-registered listener.

Specified by:

unregister in interface Log

Parameters:

l - The listener to remove. If this listener is not present, then unregister behaves as a no-op.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object