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package javax.faces.component.behavior;
import java.util.ArrayList;
import java.util.List;
import javax.faces.component.PartialStateHolder;
import javax.faces.component.UIComponentBase;
import javax.faces.context.FacesContext;
import javax.faces.event.AbortProcessingException;
import javax.faces.event.BehaviorEvent;
import javax.faces.event.BehaviorListener;
/**
* BehaviorBase is a
* convenience base class that provides a default implementation of the
* {@link Behavior} contract. It also provides behavior listener registration
* and state saving support.
*
*
* @since 2.0
*/
public class BehaviorBase implements Behavior, PartialStateHolder {
/**
* Our {@link javax.faces.event.BehaviorListener}s. This data
* structure is lazily instantiated as necessary.
*/
private List listeners;
// Flag indicating a desire to not participate in state saving.
private boolean transientFlag = false;
// Flag indicating that initial state has been marked.
private boolean initialState = false;
/**
* Default implementation of
* {@link Behavior#broadcast}. Delivers the specified
* {@link BehaviorEvent} to all registered {@link BehaviorListener}
* event listeners who have expressed an interest in events of
* this type. Listeners are called in the order in which they were
* registered (added).
*
* @param event The {@link BehaviorEvent} to be broadcast
*
* @throws AbortProcessingException Signal the JavaServer Faces
* implementation that no further processing on the current event
* should be performed
* @throws IllegalArgumentException if the implementation class
* of this {@link BehaviorEvent} is not supported by this component
* @throws NullPointerException if event is
* null
*
* @since 2.0
*/
public void broadcast(BehaviorEvent event)
throws AbortProcessingException {
if (null != listeners) {
for (BehaviorListener listener : listeners) {
if (event.isAppropriateListener(listener)) {
event.processListener(listener);
}
}
}
}
/**
* Implementation of
* {@link javax.faces.component.StateHolder#isTransient}.
*/
public boolean isTransient() {
return transientFlag;
}
/**
*
Implementation of
* {@link javax.faces.component.StateHolder#setTransient}.
*/
public void setTransient(boolean transientFlag) {
this.transientFlag = transientFlag;
}
/**
*
Implementation of
* {@link javax.faces.component.StateHolder#saveState}.
*/
public Object saveState(FacesContext context) {
if (context == null) {
throw new NullPointerException();
}
// If initial state has been marked, we don't need to
// save any state.
if (initialStateMarked()) {
return null;
}
// At the moment, the only state we need to save is our listeners
return UIComponentBase.saveAttachedState(context, listeners);
}
/**
*
Implementation of
* {@link javax.faces.component.StateHolder#restoreState}.
*/
@SuppressWarnings("unchecked")
public void restoreState(FacesContext context, Object state) {
if (context == null) {
throw new NullPointerException();
}
if (state != null) {
// Unchecked cast from Object to List
listeners = (List)UIComponentBase.restoreAttachedState(context, state);
// If we saved state last time, save state again next time.
clearInitialState();
}
}
/**
* Implementation of
* {@link javax.faces.component.PartialStateHolder#markInitialState}.
*/
public void markInitialState() {
initialState = true;
}
/**
*
Implementation of
* {@link javax.faces.component.PartialStateHolder#initialStateMarked}.
*/
public boolean initialStateMarked() {
return initialState;
}
/**
*
Clears the initial state flag, causing
* the behavior to revert from partial to full state saving.
*/
public void clearInitialState() {
initialState = false;
}
/**
* Add the specified {@link BehaviorListener}
* to the set of listeners registered to receive event notifications
* from this {@link Behavior}.
* It is expected that {@link Behavior} classes acting as event sources
* will have corresponding typesafe APIs for registering listeners of the
* required type, and the implementation of those registration methods
* will delegate to this method. For example:
*
* public class AjaxBehaviorEvent extends BehaviorEvent { ... }
*
* public interface AjaxBehaviorListener extends BehaviorListener {
* public void processAjaxBehavior(FooEvent event);
* }
*
* public class AjaxBehavior extends ClientBehaviorBase {
* ...
* public void addAjaxBehaviorListener(AjaxBehaviorListener listener) {
* addBehaviorListener(listener);
* }
* public void removeAjaxBehaviorListener(AjaxBehaviorListener listener) {
* removeBehaviorListener(listener);
* }
* ...
* }
*
*
* @param listener The {@link BehaviorListener} to be registered
*
* @throws NullPointerException if listener
* is null
*
* @since 2.0
*/
protected void addBehaviorListener(BehaviorListener listener) {
if (listener == null) {
throw new NullPointerException();
}
if (listeners == null) {
//noinspection CollectionWithoutInitialCapacity
listeners = new ArrayList();
}
listeners.add(listener);
clearInitialState();
}
/**
* Remove the specified
* {@link BehaviorListener} from the set of listeners
* registered to receive event notifications from this
* {@link Behavior}.
*
* @param listener The {@link BehaviorListener} to be deregistered
* @throws NullPointerException if listener
* is null
*
* @since 2.0
*/
protected void removeBehaviorListener(BehaviorListener listener) {
if (listener == null) {
throw new NullPointerException();
}
if (listeners == null) {
return;
}
listeners.remove(listener);
clearInitialState();
}
}