aboutsummaryrefslogtreecommitdiffstats
path: root/src/main/javassist/URLClassPath.java
blob: e58466508c845fd4d041e692f546eae9da5301fa (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
/*
 * Javassist, a Java-bytecode translator toolkit.
 * Copyright (C) 1999-2005 Shigeru Chiba. All Rights Reserved.
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License.  Alternatively, the contents of this file may be used under
 * the terms of the GNU Lesser General Public License Version 2.1 or later.
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 */

package javassist;

import java.io.*;
import java.net.*;

/**
 * A class search-path specified with URL (http).
 *
 * @see javassist.ClassPath
 * @see ClassPool#insertClassPath(ClassPath)
 * @see ClassPool#appendClassPath(ClassPath)
 */
public class URLClassPath implements ClassPath {
    protected String hostname;
    protected int port;
    protected String directory;
    protected String packageName;

    /**
     * Creates a search path specified with URL (http).
     *
     * <p>This search path is used only if a requested
     * class name starts with the name specified by <code>packageName</code>.
     * If <code>packageName</code> is "mypack" and a requested class is
     * "mypack.sub.Test", then the given URL is used for loading that class.
     * If <code>packageName</code> is <code>null</code>, the URL is used
     * for loading any class.
     *
     * @param host              host name
     * @param port              port number
     * @param directory         directory name ending with "/".
     *                          It can be "/" (root directory).
     *                          It must start with "/".
     * @param packageName       package name.
     */
    public URLClassPath(String host, int port,
                        String directory, String packageName) {
        hostname = host;
        this.port = port;
        this.directory = directory;
        this.packageName = packageName;
    }

    public String toString() {
        return hostname + ":" + port + directory;
    }

    /**
     * Opens a class file with http.
     *
     * @return null if the class file could not be found. 
     */
    public InputStream openClassfile(String classname) {
        try {
            URLConnection con = openClassfile0(classname);
            if (con != null)
                return con.getInputStream();
        }
        catch (IOException e) {}
        return null;        // not found
    }

    private URLConnection openClassfile0(String classname) throws IOException {
        if (packageName == null || classname.startsWith(packageName)) {
            String jarname
                    = directory + classname.replace('.', '/') + ".class";
            return fetchClass0(hostname, port, jarname);
        }
        else
            return null;    // not found
    }

    /**
     * Returns the URL.
     *
     * @return null if the class file could not be obtained. 
     */
    public URL find(String classname) {
        try {
            URLConnection con = openClassfile0(classname);
            InputStream is = con.getInputStream();
            if (is != null) {
                is.close();
                return con.getURL();
            }
        }
        catch (IOException e) {}
        return null; 
    }

    /**
     * Closes this class path.
     */
    public void close() {}

    /**
     * Reads a class file on an http server.
     *
     * @param host              host name
     * @param port              port number
     * @param directory         directory name ending with "/".
     *                          It can be "/" (root directory).
     *                          It must start with "/".
     * @param classname         fully-qualified class name
     */
    public static byte[] fetchClass(String host, int port,
                                    String directory, String classname)
        throws IOException
    {
        byte[] b;
        URLConnection con = fetchClass0(host, port,
                directory + classname.replace('.', '/') + ".class");
        int size = con.getContentLength();
        InputStream s = con.getInputStream();
        try {
            if (size <= 0)
                b = ClassPoolTail.readStream(s);
            else {
                b = new byte[size];
                int len = 0;
                do {
                    int n = s.read(b, len, size - len);
                    if (n < 0)
                        throw new IOException("the stream was closed: "
                                              + classname);

                    len += n;
                } while (len < size);
            }
        }
        finally {
            s.close();
        }

        return b;
    }

    private static URLConnection fetchClass0(String host, int port,
                                             String filename)
        throws IOException
    {
        URL url;
        try {
            url = new URL("http", host, port, filename);
        }
        catch (MalformedURLException e) {
            // should never reache here.
            throw new IOException("invalid URL?");
        }

        URLConnection con = url.openConnection();
        con.connect();
        return con;
    }
}