/*
* Copyright 2000-2016 Vaadin Ltd.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package com.vaadin.event;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Collection;
import java.util.EventObject;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Objects;
import java.util.logging.Logger;
import com.vaadin.server.ErrorEvent;
import com.vaadin.server.ErrorHandler;
import com.vaadin.shared.Registration;
/**
* <code>EventRouter</code> class implementing the inheritable event listening
* model. For more information on the event model see the
* {@link com.vaadin.event package documentation}.
*
* @author Vaadin Ltd.
* @since 3.0
*/
@SuppressWarnings("serial")
public class EventRouter implements MethodEventSource {
/**
* List of registered listeners.
*/
private LinkedHashSet<ListenerMethod> listenerList = null;
/*
* Registers a new listener with the specified activation method to listen
* events generated by this component. Don't add a JavaDoc comment here, we
* use the default documentation from implemented interface.
*/
@Override
public Registration addListener(Class<?> eventType, Object object,
Method method) {
Objects.requireNonNull(object, "Listener must not be null.");
if (listenerList == null) {
listenerList = new LinkedHashSet<>();
}
ListenerMethod listenerMethod = new ListenerMethod(eventType, object,
method);
listenerList.add(listenerMethod);
return () -> listenerList.remove(listenerMethod);
}
/*
* Registers a new listener with the specified named activation method to
* listen events generated by this component. Don't add a JavaDoc comment
* here, we use the default documentation from implemented interface.
*/
@Override
public Registration addListener(Class<?> eventType, Object object,
String methodName) {
Objects.requireNonNull(object, "Listener must not be null.");
if (listenerList == null) {
listenerList = new LinkedHashSet<>();
}
ListenerMethod listenerMethod = new ListenerMethod(eventType, object,
methodName);
listenerList.add(listenerMethod);
return () -> listenerList.remove(listenerMethod);
}
/*
* Removes all registered listeners matching the given parameters. Don't add
* a JavaDoc comment here, we use the default documentation from implemented
* interface.
*/
@Override
public void removeListener(Class<?> eventType, Object target) {
if (listenerList != null) {
final Iterator<ListenerMethod> i = listenerList.iterator();
while (i.hasNext()) {
final ListenerMethod lm = i.next();
if (lm.matches(eventType, target)) {
i.remove();
return;
}
}
}
}
/*
* Removes the event listener methods matching the given given paramaters.
* Don't add a JavaDoc comment here, we use the default documentation from
* implemented interface.
*/
@Override
public void removeListener(Class<?> eventType, Object target,
Method method) {
if (listenerList != null) {
final Iterator<ListenerMethod> i = listenerList.iterator();
while (i.hasNext()) {
final ListenerMethod lm = i.next();
if (lm.matches(eventType, target, method)) {
i.remove();
return;
}
}
}
}
/*
* Removes the event listener method matching the given given parameters.
* Don't add a JavaDoc comment here, we use the default documentation from
* implemented interface.
*/
@Override
public void removeListener(Class<?> eventType, Object target,
String methodName) {
// Find the correct method
final Method[] methods = target.getClass().getMethods();
Method method = null;
for (int i = 0; i < methods.length; i++) {
if (methods[i].getName().equals(methodName)) {
method = methods[i];
}
}
if (method == null) {
throw new IllegalArgumentException();
}
// Remove the listeners
if (listenerList != null) {
final Iterator<ListenerMethod> i = listenerList.iterator();
while (i.hasNext()) {
final ListenerMethod lm = i.next();
if (lm.matches(eventType, target, method)) {
i.remove();
return;
}
}
}
}
/**
* Removes all listeners from event router.
*/
public void removeAllListeners() {
listenerList = null;
}
/**
* Sends an event to all registered listeners. The listeners will decide if
* the activation method should be called or not.
*
* @param event
* the Event to be sent to all listeners.
*/
public void fireEvent(EventObject event) {
fireEvent(event, null);
}
/**
* Sends an event to all registered listeners. The listeners will decide if
* the activation method should be called or not.
* <p>
* If an error handler is set, the processing of other listeners will
* continue after the error handler method call unless the error handler
* itself throws an exception.
*
* @param event
* the Event to be sent to all listeners.
* @param errorHandler
* error handler to use to handle any exceptions thrown by
* listeners or null to let the exception propagate to the
* caller, preventing further listener calls
*/
public void fireEvent(EventObject event, ErrorHandler errorHandler) {
// It is not necessary to send any events if there are no listeners
if (listenerList != null) {
// Make a copy of the listener list to allow listeners to be added
// inside listener methods. Fixes #3605.
// Send the event to all listeners. The listeners themselves
// will filter out unwanted events.
final Object[] listeners = listenerList.toArray();
for (int i = 0; i < listeners.length; i++) {
ListenerMethod listenerMethod = (ListenerMethod) listeners[i];
if (null != errorHandler) {
try {
listenerMethod.receiveEvent(event);
} catch (Exception e) {
errorHandler.error(new ErrorEvent(e));
}
} else {
listenerMethod.receiveEvent(event);
}
}
}
}
/**
* Checks if the given Event type is listened by a listener registered to
* this router.
*
* @param eventType
* the event type to be checked
* @return true if a listener is registered for the given event type
*/
public boolean hasListeners(Class<?> eventType) {
if (listenerList != null) {
for (ListenerMethod lm : listenerList) {
if (lm.isType(eventType)) {
return true;
}
}
}
return false;
}
/**
* Returns all listeners that match or extend the given event type.
*
* @param eventType
* The type of event to return listeners for.
* @return A collection with all registered listeners. Empty if no listeners
* are found.
*/
public Collection<?> getListeners(Class<?> eventType) {
List<Object> listeners = new ArrayList<>();
if (listenerList != null) {
for (ListenerMethod lm : listenerList) {
if (lm.isOrExtendsType(eventType)) {
listeners.add(lm.getTarget());
}
}
}
return listeners;
}
private Logger getLogger() {
return Logger.getLogger(EventRouter.class.getName());
}
}