org.biomoby.service.dashboard
Class PropertyChannel

java.lang.Object
  java.util.Dictionary<K,V>
      java.util.Hashtable
          org.biomoby.service.dashboard.PropertyChannel

All Implemented Interfaces:

Serializable, Cloneable, Map

public class PropertyChannel
extends Hashtable

PropertyChannel is a shared storage for properties created by panels and their models. It is a Hashtable but extends it because whenever a value is created or updated, it also fires an event to inform about it its listeners. In other words, this channel provides its stored properties in two ways:

• A channel push way when an event is fired whenever something new happens, and
• A panel/model pull way when anytime any client can ask what is the current status of stored properties.

Additionally, it also serves as a PropertyChangeSupport object: it can register and deregister PropertyChangeListeners, and it can fire an event to them on behave of other objects. The other objects either identify themselves (see method fire(Object,String,Object)), or use this channel for firing anonymous messages (see method fire(String,Object)) - in which case the message source will be this class.

The fired events are stored here under their names. That means that you can always get the last event of a particular name.

The panels/models are sending here properties by calling method put. If we find, in the future, that sending properties here is better to do by listening to them (being a property change listener) we may re-consider this desision. At the moment, I do not see any advantage of it.

Concrete property names are of no interest for this class, but it is good to remind that they should be collected in the class DashboardProperties.

Version:

$Id: PropertyChannel.java,v 1.12 2006/02/19 18:42:55 senger Exp $

Author:

Martin Senger

See Also:

Serialized Form

Constructor Summary

PropertyChannel()
Default constructor.

Method Summary

void	addPropertyChangeListener(PropertyChangeListener l) Register listeners.
void	fire(Object source, String key, Object value) Fire an event to any registered listeners.
void	fire(String key, Object value) Fire an event to any registered listeners.
boolean	getBoolean(Object key, boolean defaultValue)
String	getString(Object key)
Object	put(Object key, Object value) Maps the specified key to the specified value in this hashtable.
Object	put(Object source, Object key, Object value) Maps the specified key to the specified value in this hashtable.
void	removePropertyChangeListener(PropertyChangeListener l) Unregister listeners.

Methods inherited from class java.util.Hashtable

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

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

PropertyChannel

public PropertyChannel()

Default constructor.

Method Detail

put

public Object put(Object key,
                  Object value)

Maps the specified key to the specified value in this hashtable. Neither the key nor the value can be null.

The given value, apart from being stored, is also propagated by firing a property change event (this is called a channel push style). The event is anonymous. If you need to send the source of the message to the listeners, use instead put(Object,Object,Object).

Specified by:

put in interface Map

Overrides:

put in class Hashtable

Parameters:

key - the hashtable key

value - the value

Returns:

the previous value of the specified key in this hashtable, or null if it did not have one

put

public Object put(Object source,
                  Object key,
                  Object value)

Maps the specified key to the specified value in this hashtable. Neither the key nor the value can be null.

The given value, apart from being stored, is also propagated by firing a property change event (this is called a channel push style). The event contains also its 'source'. For anonymously sent events, use instead put(Object,Object).

Parameters:

source - that initiated this event

key - the hashtable key

value - the value

Returns:

the previous value of the specified key in this hashtable, or null if it did not have one

getString

public String getString(Object key)

getBoolean

public boolean getBoolean(Object key,
                          boolean defaultValue)

fire

public void fire(String key,
                 Object value)

Fire an event to any registered listeners. The source of this event will be this class.

Parameters:

key - is a name of the fired event

value - is a value associated with this event

fire

public void fire(Object source,
                 String key,
                 Object value)

Fire an event to any registered listeners. The source of this event will be this class.

Parameters:

source - that initiated the event

key - is a name of the fired event

value - is a value associated with this event

addPropertyChangeListener

public void addPropertyChangeListener(PropertyChangeListener l)

Register listeners.

removePropertyChangeListener

public void removePropertyChangeListener(PropertyChangeListener l)

Unregister listeners.