| CLPath.java |
1 // Copyright 2013 Bill Campbell, Swami Iyer and Bahar Akbal-Delibas
2
3 package jminusminus;
4
5 import java.io.BufferedInputStream;
6 import java.io.File;
7 import java.io.FileInputStream;
8 import java.io.FileNotFoundException;
9 import java.io.IOException;
10 import java.util.ArrayList;
11 import java.util.StringTokenizer;
12 import java.util.zip.ZipEntry;
13 import java.util.zip.ZipFile;
14
15 /**
16 * This class can be used to locate and load system, extension, and user-defined
17 * class files from directories and zip (jar) files. The code for this class has
18 * been adapted from the Kopi (http://www.dms.at/kopi/) project.
19 */
20
21 class CLPath {
22
23 /**
24 * Stores the individual directories, zip, and jar files from the class
25 * path.
26 */
27 private ArrayList<String> dirs;
28
29 /**
30 * Return a list of conceptual directories defining the class path.
31 *
32 * @param classPath
33 * the directory names defining the class path.
34 * @return a list of conceptual directories defining the class path.
35 */
36
37 private ArrayList<String> loadClassPath(String classPath) {
38 ArrayList<String> container = new ArrayList<String>();
39
40 // Add directories/jars/zips from the classpath
41 StringTokenizer entries = new StringTokenizer(classPath,
42 File.pathSeparator);
43 while (entries.hasMoreTokens()) {
44 container.add(entries.nextToken());
45 }
46
47 // Add system directories
48 if (System.getProperty("sun.boot.class.path") != null) {
49 entries = new StringTokenizer(System
50 .getProperty("sun.boot.class.path"), File.pathSeparator);
51 while (entries.hasMoreTokens()) {
52 container.add(entries.nextToken());
53 }
54 } else {
55 float version = Float
56 .parseFloat(System.getProperty("java.version"));
57 if (version > 1.1) {
58 String dir = System.getProperty("java.home")
59 + File.separatorChar + "lib" + File.separatorChar
60 + "rt.jar";
61 container.add(dir);
62 }
63 }
64 return container;
65 }
66
67 /**
68 * Construct a CLPath object.
69 */
70
71 public CLPath() {
72 this(null, null);
73 }
74
75 /**
76 * Construct a CLPath object.
77 *
78 * @param path
79 * the directory names defining the class path, separated by path
80 * separator.
81 * @param extdir
82 * the directory for the Java extension classes.
83 */
84
85 public CLPath(String path, String extdir) {
86 if (path == null) {
87 // No path specified, use CLASSPATH
88 path = System.getProperty("java.class.path");
89 }
90 if (path == null) {
91 // Last resort, use current directory
92 path = ".";
93 }
94 dirs = loadClassPath(path);
95 if (extdir == null) {
96 // Java extension classes
97 extdir = System.getProperty("java.ext.dirs");
98 }
99 if (extdir != null) {
100 File extDirectory = new File(extdir);
101 if (extDirectory.isDirectory()) {
102 File[] extFiles = extDirectory.listFiles();
103 for (int i = 0; i < extFiles.length; i++) {
104 File file = extFiles[i];
105 if (file.isFile()
106 && (file.getName().endsWith(".zip") || file
107 .getName().endsWith(".jar"))) {
108 dirs.add(file.getName());
109 } else {
110 // Wrong suffix; ignore
111 }
112 }
113 }
114 }
115 }
116
117 /**
118 * Return a CLInputStream instance for the class with specified name
119 * (fully-qualified; tokens separated by '/') or null if the class was not
120 * found.
121 *
122 * @param name
123 * the fully-qualified name of the class -- java/util/ArrayList
124 * for example.
125 * @return a CLInputStream instance for the class with specified name or
126 * null if the class was not found.
127 */
128
129 public CLInputStream loadClass(String name) {
130 CLInputStream reader = null;
131 for (int i = 0; i < dirs.size(); i++) {
132 String dir = dirs.get(i);
133 File file = new File(dir);
134 if (file.isDirectory()) {
135 File theClass = new File(dir, name.replace('/',
136 File.separatorChar)
137 + ".class");
138 if (theClass.canRead()) {
139 try {
140 reader = new CLInputStream(new BufferedInputStream(
141 new FileInputStream(theClass)));
142 } catch (FileNotFoundException e) {
143 // Ignore
144 }
145 }
146 } else if (file.isFile()) {
147 try {
148 ZipFile zip = new ZipFile(dir);
149 ZipEntry entry = zip.getEntry(name + ".class");
150 if (entry != null) {
151 reader = new CLInputStream(zip.getInputStream(entry));
152 }
153 } catch (IOException e) {
154 // Ignore
155 }
156 } else {
157 // Bogus entry; ignore
158 }
159 }
160 return reader;
161 }
162
163 }
164