001/*
002 * (C) Copyright 2006-2011 Nuxeo SA (http://nuxeo.com/) and others.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *     http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 *
016 * Contributors:
017 *     bstefanescu
018 */
019package org.nuxeo.runtime.services.resource;
020
021import java.net.URL;
022import java.util.Map;
023import java.util.concurrent.ConcurrentHashMap;
024
025import org.nuxeo.runtime.model.ComponentContext;
026import org.nuxeo.runtime.model.ComponentInstance;
027import org.nuxeo.runtime.model.Extension;
028import org.nuxeo.runtime.model.ReloadableComponent;
029
030/**
031 * @author <a href="mailto:bs@nuxeo.com">Bogdan Stefanescu</a>
032 */
033// FIXME: make it handle hot reload correctly
034public class ResourceService extends ReloadableComponent {
035
036    public final static String XP_RESOURCES = "resources";
037
038    protected Map<String, URL> registry;
039
040    public ResourceService() {
041    }
042
043    public URL getResource(String name) {
044        return registry.get(name);
045    }
046
047    public void addResource(ResourceDescriptor resource) {
048        addResource(resource.getName(), resource.getResource().toURL());
049    }
050
051    public void addResource(String name, URL url) {
052        registry.put(name, url);
053    }
054
055    public URL removeResource(String name) {
056        return registry.remove(name);
057    }
058
059    @Override
060    public void activate(ComponentContext context) {
061        registry = new ConcurrentHashMap<String, URL>();
062    }
063
064    @Override
065    public void deactivate(ComponentContext context) {
066        registry = null;
067    }
068
069    @Override
070    public void registerContribution(Object contribution, String extensionPoint, ComponentInstance contributor) {
071        if (XP_RESOURCES.equals(extensionPoint)) {
072            addResource((ResourceDescriptor) contribution);
073        }
074    }
075
076    @Override
077    public void unregisterContribution(Object contribution, String extensionPoint, ComponentInstance contributor) {
078        if (XP_RESOURCES.equals(extensionPoint)) {
079            ResourceDescriptor rd = (ResourceDescriptor) contribution;
080            ResourceDescriptor last = findLastContributedResource(rd.getName());
081            if (last != null) {
082                addResource(last);
083            } else {
084                removeResource(rd.getName());
085            }
086        }
087    }
088
089    protected ResourceDescriptor findLastContributedResource(String name) {
090        for (int i = extensions.size() - 1; i >= 0; i--) {
091            Extension xt = extensions.get(i);
092            Object[] contribs = xt.getContributions();
093            for (int k = contribs.length - 1; k >= 0; k--) {
094                ResourceDescriptor r = (ResourceDescriptor) contribs[k];
095                if (name.equals(r.getName())) {
096                    return r;
097                }
098            }
099        }
100        return null;
101    }
102}