jakarta.faces.component.behavior.BehaviorBase Maven / Gradle / Ivy
/*
* Copyright (c) 1997, 2020 Oracle and/or its affiliates. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v. 2.0, which is available at
* http://www.eclipse.org/legal/epl-2.0.
*
* This Source Code may also be made available under the following Secondary
* Licenses when the conditions for such availability set forth in the
* Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
* version 2 with the GNU Classpath Exception, which is available at
* https://www.gnu.org/software/classpath/license.html.
*
* SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
*/
package jakarta.faces.component.behavior;
import java.util.ArrayList;
import java.util.List;
import jakarta.faces.component.PartialStateHolder;
import jakarta.faces.component.UIComponentBase;
import jakarta.faces.context.FacesContext;
import jakarta.faces.event.AbortProcessingException;
import jakarta.faces.event.BehaviorEvent;
import jakarta.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 jakarta.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 Jakarta 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
*/
@Override
public void broadcast(BehaviorEvent event) throws AbortProcessingException {
if (null == event) {
throw new NullPointerException();
}
if (null != listeners) {
for (BehaviorListener listener : listeners) {
if (event.isAppropriateListener(listener)) {
event.processListener(listener);
}
}
}
}
/**
*
* Implementation of {@link jakarta.faces.component.StateHolder#isTransient}.
*/
@Override
public boolean isTransient() {
return transientFlag;
}
/**
*
* Implementation of {@link jakarta.faces.component.StateHolder#setTransient}.
*/
@Override
public void setTransient(boolean transientFlag) {
this.transientFlag = transientFlag;
}
/**
*
* Implementation of {@link jakarta.faces.component.StateHolder#saveState}.
*/
@Override
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 jakarta.faces.component.StateHolder#restoreState}.
*/
@SuppressWarnings("unchecked")
@Override
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 jakarta.faces.component.PartialStateHolder#markInitialState}.
*/
@Override
public void markInitialState() {
initialState = true;
}
/**
*
* Implementation of {@link jakarta.faces.component.PartialStateHolder#initialStateMarked}.
*/
@Override
public boolean initialStateMarked() {
return initialState;
}
/**
*
* Clears the initial state flag, causing the behavior to revert from partial to full state saving.
*
*/
@Override
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();
}
}