org.apache.ace.webui.vaadin/src/org/apache/ace/webui/vaadin/VaadinResourceHandler.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 org.apache.ace.webui.vaadin;

import java.io.IOException;
import java.net.URL;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.osgi.framework.BundleContext;
import org.osgi.service.http.HttpContext;
import org.osgi.service.http.HttpService;

public class VaadinResourceHandler {
    private static final String RESOURCE_PATH = "/VAADIN";

    // Injected by Felix DM...
    private volatile HttpService m_http;
    private volatile BundleContext m_bundleContext;

    public void start() throws Exception {
        final HttpContext context = m_http.createDefaultHttpContext();

        m_http.registerResources(RESOURCE_PATH, RESOURCE_PATH, new HttpContext() {
            public String getMimeType(String name) {
                return context.getMimeType(name);
            }

            /**
             * ACE uses a slightly modified version of the 'reindeer' theme. To avoid having to copy all resources in
             * the Vaadin jar, we only override the files we changed and do replace the theme name 'ace' with 'reindeer'
             * before we go looking for the original files.
             * 
             * When updating to a new Vaadin version, usually you need to copy the styles.css file from the original
             * archive again and append the ACE changes to the end, as this file tends to change considerably between
             * versions.
             */
            public URL getResource(String name) {
                URL resource = null;
                // fix for ACE-156
                if (!name.startsWith("/")) {
                    name = "/".concat(name);
                }

                String prefix = RESOURCE_PATH.concat("/");
                if (name.startsWith(prefix)) {
                    String originalName = name.replace("/ace/", "/reindeer/");
                    resource = m_bundleContext.getBundle().getEntry(originalName);
                    if (resource == null) {
                        // try to find the resource in the Vaadin bundle instead
                        resource = com.vaadin.Application.class.getResource(originalName);
                    }
                }
                return resource;
            }

            public boolean handleSecurity(HttpServletRequest request, HttpServletResponse response) throws IOException {
                return context.handleSecurity(request, response);
            }
        });
    }

    public void stop() throws Exception {
        m_http.unregister(RESOURCE_PATH);
    }
}