package common.beans;
import java.beans.PropertyChangeListener;
import java.beans.PropertyChangeSupport;
/**
* Abstract base class for bean objects, which provide simple
* bean properties with change listener support.
*
* @author Benedikt Meurer
* @version $Id$
*
* @see common.beans.Bean
* @see java.beans.PropertyChangeListener
* @see java.beans.PropertyChangeSupport
*/
public abstract class AbstractBean implements Bean {
/**
* If any <code>PropertyChangeListeners</code> have been registered,
* the <code>changeSupport</code> field describes them.
*
* @serial
* @see #addPropertyChangeListener(PropertyChangeListener)
* @see #addPropertyChangeListener(String, PropertyChangeListener)
* @see #removePropertyChangeListener(PropertyChangeListener)
* @see #removePropertyChangeListener(String, PropertyChangeListener)
* @see #firePropertyChange(String, boolean, boolean)
* @see #firePropertyChange(String, int, int)
* @see #firePropertyChange(String, Object, Object)
*/
protected PropertyChangeSupport changeSupport;
//
// Constructor
//
/**
* Allocates a new abstract bean.
*/
protected AbstractBean() {
// nothing to do here...
}
//
// Listener registration
//
/**
* Adds a {@link PropertyChangeListener} to the listener list. The listener
* is registered for all bound properties of the derived class.
*
* If <code>listener</code> is <code>null</code>, no exception is thrown
* and no action is performed.
*
* @param listener the {@link PropertyChangeListener} to be added.
*
* @see #getPropertyChangeListeners()
* @see #removePropertyChangeListener(PropertyChangeListener)
*/
public synchronized void addPropertyChangeListener(PropertyChangeListener listener) {
if (listener == null) {
return;
}
if (this.changeSupport == null) {
this.changeSupport = new PropertyChangeSupport(this);
}
this.changeSupport.addPropertyChangeListener(listener);
}
/**
* Removes a {@link PropertyChangeListener} from the listener list. This method
* should be used to remove PropertyChangeListeners that were registered for all
* bound properties of this class.
*
* If <code>listener</code> is <code>null</code>, no exception is thrown and
* no action is performed.
*
* @param listener the {@link PropertyChangeListener} to be removed.
*
* @see #addPropertyChangeListener(PropertyChangeListener)
* @see #getPropertyChangeListeners()
*/
public synchronized void removePropertyChangeListener(PropertyChangeListener listener) {
if (listener == null || this.changeSupport == null) {
return;
}
this.changeSupport.removePropertyChangeListener(listener);
}
/**
* Returns an array of all the property change listeners registered
* on this object.
*
* @return all of this object's {@link PropertyChangeListener}s or an
* empty array if no property change listeners are currently
* registered.
*
* @see #addPropertyChangeListener(PropertyChangeListener)
* @see #removePropertyChangeListener(PropertyChangeListener)
*/
public synchronized PropertyChangeListener[] getPropertyChangeListeners() {
if (this.changeSupport == null) {
return new PropertyChangeListener[0];
}
return this.changeSupport.getPropertyChangeListeners();
}
/**
* Adds a {@link PropertyChangeListener} to the listener list for a specific
* property. The specified property may be user-defined, or one of the properties
* provided by the object.
*
* If <code>listener</code> is <code>null</code>, no exception is thrown and
* no action is performed.
*
* @param propertyName one of the property names of the object.
* @param listener the {@link PropertyChangeListener} to be added.
*
* @see #removePropertyChangeListener(String, PropertyChangeListener)
* @see #getPropertyChangeListeners(String)
*/
public synchronized void addPropertyChangeListener(String propertyName, PropertyChangeListener listener) {
if (listener == null) {
return;
}
if (this.changeSupport == null) {
this.changeSupport = new PropertyChangeSupport(this);
}
this.changeSupport.addPropertyChangeListener(propertyName, listener);
}
/**
* Removes a {@link PropertyChangeListener} from the listener list for a specific
* property. This method should be used to remove {@link PropertyChangeListener}s
* that were registered for a specific bound property.
*
* If <code>listener</code> is <code>null</code>, no exception is thrown and no
* action is performed.
*
* @param propertyName a valid property name.
* @param listener the {@link PropertyChangeListener} to be removed.
*
* @see #addPropertyChangeListener(String, PropertyChangeListener)
* @see #getPropertyChangeListeners(String)
*/
public synchronized void removePropertyChangeListener(String propertyName, PropertyChangeListener listener) {
if (listener == null || this.changeSupport == null) {
return;
}
this.changeSupport.removePropertyChangeListener(propertyName, listener);
}
/**
* Returns an array of all the listeners which have been associated
* with the named property.
*
* @param propertyName a valid property name.
*
* @return all of the {@link PropertyChangeListeners} associated with
* the named property or an empty array if no listeners have
* been added
*/
public synchronized PropertyChangeListener[] getPropertyChangeListeners(String propertyName) {
if (this.changeSupport == null) {
return new PropertyChangeListener[0];
}
return this.changeSupport.getPropertyChangeListeners(propertyName);
}
//
// Listener invocation
//
/**
* Support for reporting bound property changes for Object properties.
* This method can be called when a bound property has changed and it will
* send the appropriate {@link PropertyChangeEvent} to any registered
* {@link PropertyChangeListener}s.
*
* @param propertyName the property whose value has changed.
* @param oldValue the property's previous value.
* @param newValue the property's new value.
*/
protected void firePropertyChange(String propertyName, Object oldValue, Object newValue) {
PropertyChangeSupport changeSupport = this.changeSupport;
if (changeSupport == null) {
return;
}
changeSupport.firePropertyChange(propertyName, oldValue, newValue);
}
/**
* Support for reporting bound property changes for boolean properties.
* This method can be called when a bound property has changed and it will
* send the appropriate {@link PropertyChangeEvent} to any registered
* {@link PropertyChangeListener}s.
*
* @param propertyName the propery whose value has changed.
* @param oldValue the property's previous value.
* @param newValue the property's new value.
*/
protected void firePropertyChange(String propertyName, boolean oldValue, boolean newValue) {
PropertyChangeSupport changeSupport = this.changeSupport;
if (changeSupport == null) {
return;
}
changeSupport.firePropertyChange(propertyName, oldValue, newValue);
}
/**
* Support for reporting bound property changes for boolean properties.
* This method can be called when a bound property has changed and it will
* send the appropriate {@link PropertyChangeEvent} to any registered
* {@link PropertyChangeListener}s.
*
* @param propertyName the propery whose value has changed.
* @param oldValue the property's previous value.
* @param newValue the property's new value.
*/
protected void firePropertyChange(String propertyName, int oldValue, int newValue) {
PropertyChangeSupport changeSupport = this.changeSupport;
if (changeSupport == null) {
return;
}
changeSupport.firePropertyChange(propertyName, oldValue, newValue);
}
}