1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18 package com.sun.org.apache.xml.internal.resolver.helpers;
19
20 /**
21 * Static methods for dealing with public identifiers.
22 *
23 * <p>This class defines a set of static methods that can be called
24 * to handle public identifiers.</p>
25 *
26 * @author Norman Walsh
27 * <a href="mailto:Norman.Walsh@Sun.COM">Norman.Walsh@Sun.COM</a>
28 *
29 */
30 public abstract class PublicId {
31
32 protected PublicId() {}
33
34 /**
35 * Normalize a public identifier.
36 *
37 * <p>Public identifiers must be normalized according to the following
38 * rules before comparisons between them can be made:</p>
39 *
40 * <ul>
41 * <li>Whitespace characters are normalized to spaces (e.g., line feeds,
42 * tabs, etc. become spaces).</li>
43 * <li>Leading and trailing whitespace is removed.</li>
44 * <li>Multiple internal whitespaces are normalized to a single
45 * space.</li>
46 * </ul>
47 *
48 * <p>This method is declared static so that other classes
49 * can use it directly.</p>
50 *
51 * @param publicId The unnormalized public identifier.
52 *
53 * @return The normalized identifier.
54 */
55 public static String normalize(String publicId) {
56 String normal = publicId.replace('\t', ' ');
57 normal = normal.replace('\r', ' ');
58 normal = normal.replace('\n', ' ');
59 normal = normal.trim();
60
61 int pos;
62
63 while ((pos = normal.indexOf(" ")) >= 0) {
64 normal = normal.substring(0, pos) + normal.substring(pos+1);
65 }
66 return normal;
67 }
68
69 /**
70 * Encode a public identifier as a "publicid" URN.
71 *
72 * <p>This method is declared static so that other classes
73 * can use it directly.</p>
74 *
75 * @param publicId The unnormalized public identifier.
76 *
77 * @return The normalized identifier.
78 */
79 public static String encodeURN(String publicId) {
80 String urn = PublicId.normalize(publicId);
81
82 urn = PublicId.stringReplace(urn, "%", "%25");
83 urn = PublicId.stringReplace(urn, ";", "%3B");
84 urn = PublicId.stringReplace(urn, "'", "%27");
85 urn = PublicId.stringReplace(urn, "?", "%3F");
86 urn = PublicId.stringReplace(urn, "#", "%23");
87 urn = PublicId.stringReplace(urn, "+", "%2B");
88 urn = PublicId.stringReplace(urn, " ", "+");
89 urn = PublicId.stringReplace(urn, "::", ";");
90 urn = PublicId.stringReplace(urn, ":", "%3A");
91 urn = PublicId.stringReplace(urn, "//", ":");
92 urn = PublicId.stringReplace(urn, "/", "%2F");
93
94 StringBuilder buffer = new StringBuilder(13 + urn.length());
95 buffer.append("urn:publicid:");
96 buffer.append(urn);
97 return buffer.toString();
98 }
99
100 /**
101 * Decode a "publicid" URN into a public identifier.
102 *
103 * <p>This method is declared static so that other classes
104 * can use it directly.</p>
105 *
106 * @param urn The urn:publicid: URN
107 *
108 * @return The normalized identifier.
109 */
110 public static String decodeURN(String urn) {
111 String publicId;
112 if (urn.startsWith("urn:publicid:")) {
113 publicId = urn.substring(13);
114 }
115 else {
116 return urn;
117 }
118
119 final boolean hasEscape = (publicId.indexOf('%') >= 0);
120 if (hasEscape) {
121 publicId = PublicId.stringReplace(publicId, "%2F", "/");
122 }
123 publicId = PublicId.stringReplace(publicId, ":", "//");
124 if (hasEscape) {
125 publicId = PublicId.stringReplace(publicId, "%3A", ":");
126 }
127 publicId = PublicId.stringReplace(publicId, ";", "::");
128 publicId = PublicId.stringReplace(publicId, "+", " ");
129 if (hasEscape) {
130 publicId = PublicId.stringReplace(publicId, "%2B", "+");
131 publicId = PublicId.stringReplace(publicId, "%23", "#");
132 publicId = PublicId.stringReplace(publicId, "%3F", "?");
133 publicId = PublicId.stringReplace(publicId, "%27", "'");
134 publicId = PublicId.stringReplace(publicId, "%3B", ";");
135 publicId = PublicId.stringReplace(publicId, "%25", "%");
136 }
137
138 return publicId;
139 }
140
141 /**
142 * Replace one string with another.
143 */
144 private static String stringReplace(String str,
145 String oldStr,
146 String newStr) {
147 int pos = str.indexOf(oldStr);
148 if (pos >= 0) {
149 final StringBuilder buffer = new StringBuilder();
150 final int oldStrLength = oldStr.length();
151 int start = 0;
152 do {
153 for (int i = start; i < pos; ++i) {
154 buffer.append(str.charAt(i));
155 }
156 buffer.append(newStr);
157 start = pos + oldStrLength;
158 pos = str.indexOf(oldStr, start);
159 }
160 while (pos >= 0);
161 final int strLength = str.length();
162 for (int i = start; i < strLength; ++i) {
163 buffer.append(str.charAt(i));
164 }
165 return buffer.toString();
166 }
167 return str;
168 }
169 }