Cocoon API: Class Monitor

org.apache.cocoon.framework
Class Monitor

java.lang.Object
  |
  +--java.util.Dictionary
        |
        +--java.util.Hashtable
              |
              +--org.apache.cocoon.framework.Monitor

All Implemented Interfaces:

java.lang.Cloneable, java.util.Map, java.io.Serializable

public class Monitor

extends java.util.Hashtable

This class watches over the changes of indicated resources.

Version:

$Revision: 1.8 $ $Date: 2000/04/14 17:12:57 $

Author:

Stefano Mazzocchi

See Also:

Serialized Form

Inner classes inherited from class java.util.Map

java.util.Map.Entry

Constructor Summary

Monitor(int capacity)
Create this class with the given starting capacity.

Method Summary

boolean	hasChanged(java.lang.Object context) Queries the monitor for changes.
void	invalidate(java.lang.Object context) Invalidates the given context.
static long	timestamp(java.lang.Object resource) Create a timestamp indicating the last modified time of the given resource.
void	watch(java.lang.Object key, java.lang.Object resource) Tells the monitor to watch the given resource, timestamps it and associate it to the given key.

Methods inherited from class java.util.Hashtable

clear, clone, contains, containsKey, containsValue, elements, entrySet, equals, get, hashCode, isEmpty, keys, keySet, put, putAll, rehash, remove, size, toString, values

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

Monitor

public Monitor(int capacity)

Create this class with the given starting capacity.

Method Detail

watch

public void watch(java.lang.Object key,
                  java.lang.Object resource)

Tells the monitor to watch the given resource, timestamps it and associate it to the given key.

hasChanged

public boolean hasChanged(java.lang.Object context)

Queries the monitor for changes. For maximum reliability, this method is synchronous, but less reliable for faster asynchronous versions could be implemented. Returns true if the resource associated to the given key has changed since the last call to watch. WARNING: due to a stupid bug in "FileURLConnection", the class that implements the "file:" protocol for the java.net.URL framework, the getLastModified() method always returns 0. For this reason, the use of the File resource is strongly suggested over the "file:" type URL. NOTE: this may not be (and should not be) the case in other virtual machine implementations or if we rewrite the URL handler ourselves (which I don't care to do at this point).

invalidate

public void invalidate(java.lang.Object context)

Invalidates the given context.

timestamp

public static long timestamp(java.lang.Object resource)

Create a timestamp indicating the last modified time of the given resource.