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.FileInputStream;
23import java.io.InputStreamReader;
24import java.io.IOException;
25import java.io.Reader;
26
27/**
28 * Loads resources from a directory.
29 *
30 * @see ResourceLoader
31 */
32public class FileSystemResourceLoader extends BufferedResourceLoader {
33
34  private final File rootDir;
35
36  public FileSystemResourceLoader(File rootDir) {
37    this.rootDir = rootDir;
38  }
39
40  public FileSystemResourceLoader(String rootDir) {
41    this(new File(rootDir));
42  }
43
44  @Override
45  public Reader open(String name) throws IOException {
46    File file = new File(rootDir, name);
47    // Check for non-directory rather than is-file so that reads from
48    // e.g. pipes work.
49    if (file.exists() && !file.isDirectory() && file.canRead()) {
50      return buffer(new InputStreamReader(new FileInputStream(file), getCharacterSet()));
51    } else {
52      return null;
53    }
54  }
55
56  @Override
57  public Reader openOrFail(String name) throws JSilverTemplateNotFoundException, IOException {
58    Reader reader = open(name);
59    if (reader == null) {
60      throw new JSilverTemplateNotFoundException("No file '" + name + "' inside directory '"
61          + rootDir + "'");
62    } else {
63      return reader;
64    }
65  }
66
67  /**
68   * Some applications, e.g. online help, need to know when a file has changed due to a symlink
69   * modification hence the use of {@link File#getCanonicalFile()}, if possible.
70   */
71  @Override
72  public Object getResourceVersionId(String filename) {
73    File file = new File(rootDir, filename);
74    // Check for non-directory rather than is-file so that reads from
75    // e.g. pipes work.
76    if (file.exists() && !file.isDirectory() && file.canRead()) {
77      String fullPath;
78      try {
79        fullPath = file.getCanonicalPath();
80      } catch (IOException e) {
81        fullPath = file.getAbsolutePath();
82      }
83      return String.format("%s@%s", fullPath, file.lastModified());
84    } else {
85      return null;
86    }
87  }
88}
89