1 /*
2 * Copyright 2002-2009 the original author or authors.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 package org.springframework.core.io;
18
19 import java.net.MalformedURLException;
20 import java.net.URL;
21
22 import org.springframework.util.Assert;
23 import org.springframework.util.ClassUtils;
24 import org.springframework.util.StringUtils;
25
26 /**
27 * Default implementation of the {@link ResourceLoader} interface.
28 * Used by {@link ResourceEditor}, and serves as base class for
29 * {@link org.springframework.context.support.AbstractApplicationContext}.
30 * Can also be used standalone.
31 *
32 * <p>Will return a {@link UrlResource} if the location value is a URL,
33 * and a {@link ClassPathResource} if it is a non-URL path or a
34 * "classpath:" pseudo-URL.
35 *
36 * @author Juergen Hoeller
37 * @since 10.03.2004
38 * @see FileSystemResourceLoader
39 * @see org.springframework.context.support.ClassPathXmlApplicationContext
40 */
41 public class DefaultResourceLoader implements ResourceLoader {
42
43 private ClassLoader classLoader;
44
45
46 /**
47 * Create a new DefaultResourceLoader.
48 * <p>ClassLoader access will happen using the thread context class loader
49 * at the time of this ResourceLoader's initialization.
50 * @see java.lang.Thread#getContextClassLoader()
51 */
52 public DefaultResourceLoader() {
53 this.classLoader = ClassUtils.getDefaultClassLoader();
54 }
55
56 /**
57 * Create a new DefaultResourceLoader.
58 * @param classLoader the ClassLoader to load class path resources with, or <code>null</code>
59 * for using the thread context class loader at the time of actual resource access
60 */
61 public DefaultResourceLoader(ClassLoader classLoader) {
62 this.classLoader = classLoader;
63 }
64
65
66 /**
67 * Specify the ClassLoader to load class path resources with, or <code>null</code>
68 * for using the thread context class loader at the time of actual resource access.
69 * <p>The default is that ClassLoader access will happen using the thread context
70 * class loader at the time of this ResourceLoader's initialization.
71 */
72 public void setClassLoader(ClassLoader classLoader) {
73 this.classLoader = classLoader;
74 }
75
76 /**
77 * Return the ClassLoader to load class path resources with.
78 * <p>Will get passed to ClassPathResource's constructor for all
79 * ClassPathResource objects created by this resource loader.
80 * @see ClassPathResource
81 */
82 public ClassLoader getClassLoader() {
83 return (this.classLoader != null ? this.classLoader : ClassUtils.getDefaultClassLoader());
84 }
85
86
87 public Resource getResource(String location) {
88 Assert.notNull(location, "Location must not be null");
89 if (location.startsWith(CLASSPATH_URL_PREFIX)) {
90 return new ClassPathResource(location.substring(CLASSPATH_URL_PREFIX.length()), getClassLoader());
91 }
92 else {
93 try {
94 // Try to parse the location as a URL...
95 URL url = new URL(location);
96 return new UrlResource(url);
97 }
98 catch (MalformedURLException ex) {
99 // No URL -> resolve as resource path.
100 return getResourceByPath(location);
101 }
102 }
103 }
104
105 /**
106 * Return a Resource handle for the resource at the given path.
107 * <p>The default implementation supports class path locations. This should
108 * be appropriate for standalone implementations but can be overridden,
109 * e.g. for implementations targeted at a Servlet container.
110 * @param path the path to the resource
111 * @return the corresponding Resource handle
112 * @see ClassPathResource
113 * @see org.springframework.context.support.FileSystemXmlApplicationContext#getResourceByPath
114 * @see org.springframework.web.context.support.XmlWebApplicationContext#getResourceByPath
115 */
116 protected Resource getResourceByPath(String path) {
117 return new ClassPathContextResource(path, getClassLoader());
118 }
119
120
121 /**
122 * ClassPathResource that explicitly expresses a context-relative path
123 * through implementing the ContextResource interface.
124 */
125 private static class ClassPathContextResource extends ClassPathResource implements ContextResource {
126
127 public ClassPathContextResource(String path, ClassLoader classLoader) {
128 super(path, classLoader);
129 }
130
131 public String getPathWithinContext() {
132 return getPath();
133 }
134
135 @Override
136 public Resource createRelative(String relativePath) {
137 String pathToUse = StringUtils.applyRelativePath(getPath(), relativePath);
138 return new ClassPathContextResource(pathToUse, getClassLoader());
139 }
140 }
141
142 }