org.valkyriercp.binding.value.ValueModel Maven / Gradle / Ivy
package org.valkyriercp.binding.value;
import java.beans.PropertyChangeListener;
/**
* Describes models with a generic access to a single value that allow
* to observe value changes. The value can be accessed using the
* #getValue()/#setValue(Object)/
* #setValueSilently(Object, PropertyChangeListener)
* methods. Observers can register instances of PropertyChangeListener
* to be notified if the value changes.
*
* The listeners registered with this ValueModel using #addValueChangeListener
* will be invoked only with PropertyChangeEvents that have the name set to
* "value".
*
*
AbstractValueModel minimizes the effort required to implement this interface.
* It uses the PropertyChangeSupport to fire PropertyChangeEvents, and it adds
* PropertyChangeListeners for the specific property name "value". This ensures
* that the constraint mentioned above is met.
*
* @see org.springframework.binding.value.support.AbstractValueModel
*
* @author Karsten Lentzsch
* @author Keith Donald
* @author Oliver Hutchison
*/
public interface ValueModel {
/**
* The name of the bound property value.
*/
String VALUE_PROPERTY = "value";
/**
* Returns this model's value. In case of a write-only value,
* implementers may choose to either reject this operation or
* or return null or any other appropriate value.
*
* @return this model's value
*/
Object getValue();
/**
* Sets a new value and if the value has changed notifies any registered
* value change listeners.
*
* @param newValue the value to be set
*/
void setValue(Object newValue);
/**
* Sets a new value and if the value has changed notifies all registered
* value change listeners except for the specified listener to skip.
*
* @param newValue the value to be set
* @param listenerToSkip the PropertyChangeListener that should
* not be notified of this change (may be null).
*/
void setValueSilently(Object newValue, PropertyChangeListener listenerToSkip);
/**
* Registers the given PropertyChangeListener with this
* ValueModel. The listener will be notified if the value has changed.
* The PropertyChangeEvents delivered to the listener must have the name
* set to "value". The latter ensures that all ValueModel implementers
* behave like the AbstractValueModel subclasses.
*
* To comply with the above specification implementers can use
* the PropertyChangeSupport's #addPropertyChangeListener method
* that accepts a property name, so that listeners will be invoked only
* if that specific property has changed.
*
* @param listener the listener to be added
*
* @see org.springframework.binding.value.support.AbstractValueModel#addValueChangeListener(PropertyChangeListener)
*/
void addValueChangeListener(PropertyChangeListener listener);
/**
* Deregisters the given PropertyChangeListener from this
* ValueModel.
*
* @param listener the listener to be removed
*/
void removeValueChangeListener(PropertyChangeListener listener);
}