001/*
002  GRANITE DATA SERVICES
003  Copyright (C) 2011 GRANITE DATA SERVICES S.A.S.
004
005  This file is part of Granite Data Services.
006
007  Granite Data Services is free software; you can redistribute it and/or modify
008  it under the terms of the GNU Library General Public License as published by
009  the Free Software Foundation; either version 2 of the License, or (at your
010  option) any later version.
011
012  Granite Data Services is distributed in the hope that it will be useful, but
013  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
014  FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public License
015  for more details.
016
017  You should have received a copy of the GNU Library General Public License
018  along with this library; if not, see <http://www.gnu.org/licenses/>.
019*/
020
021package org.granite.tide.util;
022
023import java.lang.reflect.Method;
024import java.util.ArrayList;
025import java.util.HashMap;
026import java.util.List;
027import java.util.Map;
028import java.util.Set;
029
030import org.granite.logging.Logger;
031import org.granite.tide.invocation.ContextEvent;
032
033/**
034 * @author Franck WOLFF
035 */
036public abstract class AbstractContext extends HashMap<String, Object> {
037
038        private static final long serialVersionUID = 1L;
039        private static final Logger log = Logger.getLogger(AbstractContext.class);
040        private static final ThreadLocal<AbstractContext> contexts = new ThreadLocal<AbstractContext>();
041        
042        private final Map<String, Set<Method>> observers;
043        private final List<ContextEvent> remoteEvents;
044        
045        protected AbstractContext(Map<String, Set<Method>> observers) {
046                synchronized (contexts) {
047                        if (contexts.get() != null)
048                                throw new IllegalStateException("Context already created");
049                        
050                        this.observers = observers;
051                        this.remoteEvents = new ArrayList<ContextEvent>();
052                        
053                        contexts.set(this);
054                }
055        }
056        
057        public List<ContextEvent> getRemoteEvents() {
058                return remoteEvents;
059        }
060        
061        protected abstract Set<String> getRemoteObservers();
062        protected abstract Object callMethod(Method method, Object... args) throws Exception;
063        
064        public static AbstractContext instance() {
065                return contexts.get();
066        }
067        
068        public static void raiseEvent(String name, Object... args) {
069                AbstractContext instance = instance();
070                Map<String, Set<Method>> observers = instance.observers;
071                if (observers.containsKey(name)) {
072                        for (Method method : observers.get(name)) {
073                                try {
074                                        instance.callMethod(method, args);
075                                }
076                                catch (Exception e) {
077                                        log.error(e, "Could not call method: %s", method);
078                                }
079                        }
080                }
081                Set<String> remoteObservers = instance.getRemoteObservers();
082                if (remoteObservers.contains(name))
083                        instance.remoteEvents.add(new ContextEvent(name, args));
084        }
085        
086        public static void remove() {
087                AbstractContext context = contexts.get();
088                if (context != null) {
089                        try {
090                                context.clear();
091                                context.remoteEvents.clear();
092                        }
093                        finally {
094                                contexts.remove();
095                        }
096                }
097        }
098}