1 /*
2 * Copyright 2002-2007 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 org.springframework.util.ResourceUtils;
20
21 /**
22 * Strategy interface for loading resources (e.. class path or file system
23 * resources). An {@link org.springframework.context.ApplicationContext}
24 * is required to provide this functionality, plus extended
25 * {@link org.springframework.core.io.support.ResourcePatternResolver} support.
26 *
27 * <p>{@link DefaultResourceLoader} is a standalone implementation that is
28 * usable outside an ApplicationContext, also used by {@link ResourceEditor}.
29 *
30 * <p>Bean properties of type Resource and Resource array can be populated
31 * from Strings when running in an ApplicationContext, using the particular
32 * context's resource loading strategy.
33 *
34 * @author Juergen Hoeller
35 * @since 10.03.2004
36 * @see Resource
37 * @see org.springframework.core.io.support.ResourcePatternResolver
38 * @see org.springframework.context.ApplicationContext
39 * @see org.springframework.context.ResourceLoaderAware
40 */
41 public interface ResourceLoader {
42
43 /** Pseudo URL prefix for loading from the class path: "classpath:" */
44 String CLASSPATH_URL_PREFIX = ResourceUtils.CLASSPATH_URL_PREFIX;
45
46
47 /**
48 * Return a Resource handle for the specified resource.
49 * The handle should always be a reusable resource descriptor,
50 * allowing for multiple {@link Resource#getInputStream()} calls.
51 * <p><ul>
52 * <li>Must support fully qualified URLs, e.g. "file:C:/test.dat".
53 * <li>Must support classpath pseudo-URLs, e.g. "classpath:test.dat".
54 * <li>Should support relative file paths, e.g. "WEB-INF/test.dat".
55 * (This will be implementation-specific, typically provided by an
56 * ApplicationContext implementation.)
57 * </ul>
58 * <p>Note that a Resource handle does not imply an existing resource;
59 * you need to invoke {@link Resource#exists} to check for existence.
60 * @param location the resource location
61 * @return a corresponding Resource handle
62 * @see #CLASSPATH_URL_PREFIX
63 * @see org.springframework.core.io.Resource#exists
64 * @see org.springframework.core.io.Resource#getInputStream
65 */
66 Resource getResource(String location);
67
68 /**
69 * Expose the ClassLoader used by this ResourceLoader.
70 * <p>Clients which need to access the ClassLoader directly can do so
71 * in a uniform manner with the ResourceLoader, rather than relying
72 * on the thread context ClassLoader.
73 * @return the ClassLoader (never <code>null</code>)
74 */
75 ClassLoader getClassLoader();
76
77 }