/*
* Copyright (C) 2013 Glyptodon LLC
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package org.glyptodon.guacamole.net.basic.event;
import java.lang.reflect.InvocationTargetException;
import java.util.AbstractCollection;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import javax.servlet.http.HttpSession;
import org.glyptodon.guacamole.GuacamoleException;
import org.glyptodon.guacamole.net.basic.properties.BasicGuacamoleProperties;
import org.glyptodon.guacamole.properties.GuacamoleProperties;
/**
* A collection which iterates over instances of all listeners defined in
* guacamole.properties. For each listener defined in guacamole.properties, a
* new instance is created and stored in this collection. The contents of this
* collection is stored within the HttpSession, and will be reused if available.
* Each listener is instantiated once per session. Listeners are singleton
* classes within the session, but not globally.
*
* @author Michael Jumper
*/
public class SessionListenerCollection extends AbstractCollection {
/**
* The name of the session attribute which will contain the listener
* collection.
*/
private static final String SESSION_ATTRIBUTE = "GUAC_LISTENERS";
/**
* The wrapped collection of listeners, possibly retrieved from the
* session.
*/
private Collection listeners;
/**
* Creates a new SessionListenerCollection which stores all listeners
* defined in guacamole.properties in the provided session. If listeners
* are already stored in the provided session, those listeners are used
* instead.
*
* @param session The HttpSession to store listeners within.
* @throws GuacamoleException If an error occurs while instantiating new
* listeners.
*/
public SessionListenerCollection(HttpSession session) throws GuacamoleException {
// Pull cached listeners from session
listeners = (Collection) session.getAttribute(SESSION_ATTRIBUTE);
// If no listeners stored, listeners must be loaded first
if (listeners == null) {
// Load listeners from guacamole.properties
listeners = new ArrayList();
try {
// Get all listener classes from properties
Collection<Class> listenerClasses =
GuacamoleProperties.getProperty(BasicGuacamoleProperties.EVENT_LISTENERS);
// Add an instance of each class to the list
if (listenerClasses != null) {
for (Class listenerClass : listenerClasses) {
// Instantiate listener
Object listener = listenerClass.getConstructor().newInstance();
// Add listener to collection of listeners
listeners.add(listener);
}
}
}
catch (InstantiationException e) {
throw new GuacamoleException("Listener class is abstract.", e);
}
catch (IllegalAccessException e) {
throw new GuacamoleException("No access to listener constructor.", e);
}
catch (IllegalArgumentException e) {
// This should not happen, given there ARE no arguments
throw new GuacamoleException("Illegal arguments to listener constructor.", e);
}
catch (InvocationTargetException e) {
throw new GuacamoleException("Error while instantiating listener.", e);
}
catch (NoSuchMethodException e) {
throw new GuacamoleException("Listener has no default constructor.", e);
}
catch (SecurityException e) {
throw new GuacamoleException("Security restrictions prevent instantiation of listener.", e);
}
// Store listeners for next time
session.setAttribute(SESSION_ATTRIBUTE, listeners);
}
}
@Override
public Iterator iterator() {
return listeners.iterator();
}
@Override
public int size() {
return listeners.size();
}
}