1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 */
19 package org.apache.myfaces.renderkit.html.util;
20
21 import javax.faces.context.FacesContext;
22
23 /**
24 * Represents a single resource that a component in a page needs a
25 * browser to fetch. This class helps generate the URI that is emitted
26 * into the page, and specifies the class that should be invoked to
27 * handle the request for that URI when the browser makes it.
28 *
29 * @author Mathias Broekelmann
30 */
31 public interface ResourceHandler
32 {
33 /**
34 * Return a Class object whose instance can decode the url generated
35 * by this class in the getResourceUri method and use that info to
36 * locate the resource data represented by this object. When a
37 * browser requests the data in the URL generated by this class
38 * and its callers, an instance of the returned class shall be
39 * created to decode the remainder of the url and serve the
40 * resource.
41 *
42 * @return a class which implements
43 * org.apache.myfaces.component.html.util.ResourceLoader
44 *
45 * @see ResourceLoader
46 */
47 public Class getResourceLoaderClass();
48
49 /**
50 * Returns the uri part which is used by the resourceloader to
51 * identify the resource to load. This URI will be interpreted
52 * by an instance of the class returned by getResourceLoaderClass.
53 *
54 * @see org.apache.myfaces.renderkit.html.util.ResourceLoader#serveResource(javax.servlet.ServletContext, javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse, String)
55 */
56 public String getResourceUri(FacesContext context);
57
58 /**
59 * Must always be implemented when equals is overridden.
60 *
61 * @see java.lang.Object#hashCode()
62 */
63 public int hashCode();
64
65 /**
66 * Must be implemented to avoid loading the same resource multiple times.
67 * <p>
68 * When the same component is used multiple times in a page and that
69 * component needs an external resource such as a script, multiple calls
70 * will be made to the AddResource methods for the same resource. The
71 * AddResource class will create an instance of this class for each such
72 * call. However if there is already a ResourceHandler instance existing
73 * which is "equal" to the newly created one then a duplicate will not
74 * be queued for output.
75 *
76 * @see java.lang.Object#equals(java.lang.Object)
77 */
78 public boolean equals(Object obj);
79 }