1/*
2 * Copyright (C) 2010 Google Inc.
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
17package com.google.clearsilver.jsilver.resourceloader;
18
19import com.google.clearsilver.jsilver.exceptions.JSilverTemplateNotFoundException;
20
21import java.io.File;
22import java.io.IOException;
23import java.io.InputStream;
24import java.io.InputStreamReader;
25import java.io.Reader;
26
27/**
28 * Loads resources from classpath.
29 *
30 * <p>
31 * For example, suppose the classpath contains:
32 *
33 * <pre>
34 * com/foo/my-template.cs
35 * com/foo/subdir/another-template.cs
36 * </pre>
37 *
38 * <p>
39 * You can access the resources like this:
40 *
41 * <pre>
42 * ResourceLoader loader =
43 *     new ClassPathResourceLoader(getClassLoader(), "com/foo");
44 * loader.open("my-template.cs");
45 * loader.open("subdir/my-template.cs");
46 * </pre>
47 *
48 * @see ResourceLoader
49 * @see ClassResourceLoader
50 */
51public class ClassLoaderResourceLoader extends BufferedResourceLoader {
52
53  private final ClassLoader classLoader;
54  private String basePath;
55
56  public ClassLoaderResourceLoader(ClassLoader classLoader, String basePath) {
57    this.classLoader = classLoader;
58    this.basePath = basePath;
59  }
60
61  public ClassLoaderResourceLoader(ClassLoader classLoader) {
62    this(classLoader, ".");
63  }
64
65  @Override
66  public Reader open(String name) throws IOException {
67    String path = basePath + '/' + name;
68    InputStream stream = classLoader.getResourceAsStream(path);
69    return stream == null ? null : buffer(new InputStreamReader(stream, getCharacterSet()));
70  }
71
72  @Override
73  public Reader openOrFail(String name) throws JSilverTemplateNotFoundException, IOException {
74    Reader reader = open(name);
75    if (reader == null) {
76      throw new JSilverTemplateNotFoundException("No class loader resource '" + name + "' in '"
77          + basePath + "'");
78    } else {
79      return reader;
80    }
81  }
82
83}
84