1/*
2 * Copyright (c) 1998, 2004, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26package sun.security.util;
27
28import java.net.URI;
29import java.net.URISyntaxException;
30import java.security.GeneralSecurityException;
31
32/**
33 * A utility class to expand properties embedded in a string.
34 * Strings of the form ${some.property.name} are expanded to
35 * be the value of the property. Also, the special ${/} property
36 * is expanded to be the same as file.separator. If a property
37 * is not set, a GeneralSecurityException will be thrown.
38 *
39 * @author Roland Schemers
40 */
41public class PropertyExpander {
42
43
44    public static class ExpandException extends GeneralSecurityException {
45
46        private static final long serialVersionUID = -7941948581406161702L;
47
48        public ExpandException(String msg) {
49            super(msg);
50        }
51    }
52
53    public static String expand(String value)
54        throws ExpandException
55    {
56        return expand(value, false);
57    }
58
59     public static String expand(String value, boolean encodeURL)
60         throws ExpandException
61     {
62        if (value == null)
63            return null;
64
65        int p = value.indexOf("${", 0);
66
67        // no special characters
68        if (p == -1) return value;
69
70        StringBuffer sb = new StringBuffer(value.length());
71        int max = value.length();
72        int i = 0;  // index of last character we copied
73
74    scanner:
75        while (p < max) {
76            if (p > i) {
77                // copy in anything before the special stuff
78                sb.append(value.substring(i, p));
79                i = p;
80            }
81            int pe = p+2;
82
83            // do not expand ${{ ... }}
84            if (pe < max && value.charAt(pe) == '{') {
85                pe = value.indexOf("}}", pe);
86                if (pe == -1 || pe+2 == max) {
87                    // append remaining chars
88                    sb.append(value.substring(p));
89                    break scanner;
90                } else {
91                    // append as normal text
92                    pe++;
93                    sb.append(value.substring(p, pe+1));
94                }
95            } else {
96                while ((pe < max) && (value.charAt(pe) != '}')) {
97                    pe++;
98                }
99                if (pe == max) {
100                    // no matching '}' found, just add in as normal text
101                    sb.append(value.substring(p, pe));
102                    break scanner;
103                }
104                String prop = value.substring(p+2, pe);
105                if (prop.equals("/")) {
106                    sb.append(java.io.File.separatorChar);
107                } else {
108                    String val = System.getProperty(prop);
109                    if (val != null) {
110                        if (encodeURL) {
111                            // encode 'val' unless it's an absolute URI
112                            // at the beginning of the string buffer
113                            try {
114                                if (sb.length() > 0 ||
115                                    !(new URI(val)).isAbsolute()) {
116                                    val = sun.net.www.ParseUtil.encodePath(val);
117                                }
118                            } catch (URISyntaxException use) {
119                                val = sun.net.www.ParseUtil.encodePath(val);
120                            }
121                        }
122                        sb.append(val);
123                    } else {
124                        throw new ExpandException(
125                                             "unable to expand property " +
126                                             prop);
127                    }
128                }
129            }
130            i = pe+1;
131            p = value.indexOf("${", i);
132            if (p == -1) {
133                // no more to expand. copy in any extra
134                if (i < max) {
135                    sb.append(value.substring(i, max));
136                }
137                // break out of loop
138                break scanner;
139            }
140        }
141        return sb.toString();
142    }
143}
144