org.apache.ode.utils

Class WatchDog<T,C extends WatchDog.Observer>

java.lang.Object

org.apache.ode.utils.WatchDog<T,C>

All Implemented Interfaces:

java.lang.Runnable

public class WatchDog<T,C extends WatchDog.Observer>
extends java.lang.Object
implements java.lang.Runnable

This class is based on org.apache.log4j.helpers.FileWatchdog.

Modifications have been made to support additional abstract ressource and more events (creation, deletion and updates), and to allow "manual" invocations of check() (i.e wihtout having to use a thread) while preserving time checking.

Now two use cases coexist:

1. Pass an instance of WatchDog to a new thread (WatchDog is a Runnable). So that check () will be called automatically every delay milliseconds.
2. Invoke check () only when you feel like it. If the expiration date previously set is lower than NOW then event callback methods will be invoked accordingly.

Author:

Alexis Midon

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	WatchDog.DefaultObserver<A> A default implementation of #ChangeHandler.
static class	WatchDog.FileMutable
static class	WatchDog.FileSetMutable
static interface	WatchDog.Mutable<T> have you said that duck typing would be nice?
static interface	WatchDog.Observer<A>

Field Summary

Fields

Modifier and Type	Field and Description
static long	DEFAULT_DELAY
protected WatchDog.Mutable<T>	mutable
protected C	observer

Constructor Summary

Constructors

Constructor and Description
WatchDog()
WatchDog(WatchDog.Mutable<T> mutable)
WatchDog(WatchDog.Mutable<T> mutable, C observer)
WatchDog(WatchDog.Mutable<T> mutable, long delay)

Method Summary

Methods

Modifier and Type	Method and Description
void	check()
long	getDelay()
WatchDog.Mutable<T>	getMutable()
C	getObserver()
void	run()
void	setDelay(long delay)
static <C extends WatchDog.Observer> WatchDog<java.lang.Long,C>	watchFile(java.io.File file, C handler)
static <C extends WatchDog.Observer> WatchDog<java.util.Map<java.io.File,java.lang.Long>,C>	watchFiles(java.util.List<java.io.File> files, C handler)

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_DELAY

public static final long DEFAULT_DELAY

See Also:

Constant Field Values

mutable

protected WatchDog.Mutable<T> mutable

observer

protected C extends WatchDog.Observer observer

Constructor Detail

WatchDog

public WatchDog()

WatchDog

public WatchDog(WatchDog.Mutable<T> mutable,
        long delay)

Parameters:

mutable - the object to watch closely

delay - between two checks

WatchDog

public WatchDog(WatchDog.Mutable<T> mutable,
        C observer)

WatchDog

public WatchDog(WatchDog.Mutable<T> mutable)

See Also:

WatchDog(org.apache.ode.utils.WatchDog.Mutable, long)

Method Detail

getMutable

public WatchDog.Mutable<T> getMutable()

getObserver

public C getObserver()

getDelay

public long getDelay()

setDelay

public void setDelay(long delay)

run

public void run()

Specified by:

run in interface java.lang.Runnable

check

public final void check()

watchFile

public static <C extends WatchDog.Observer> WatchDog<java.lang.Long,C> watchFile(java.io.File file,
                                                                 C handler)

watchFiles

public static <C extends WatchDog.Observer> WatchDog<java.util.Map<java.io.File,java.lang.Long>,C> watchFiles(java.util.List<java.io.File> files,
                                                                                              C handler)