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Java > Open Source Codes > org > apache > commons > httpclient > util > ParameterParser


1 /*
2  * $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//httpclient/src/java/org/apache/commons/httpclient/util/ParameterParser.java,v 1.5 2004/05/13 04:01:22 mbecke Exp $
3  * $Revision: 480424 $
4  * $Date: 2006-11-29 05:56:49 +0000 (Wed, 29 Nov 2006) $
5  *
6  * ====================================================================
7  *
8  * Licensed to the Apache Software Foundation (ASF) under one or more
9  * contributor license agreements. See the NOTICE file distributed with
10  * this work for additional information regarding copyright ownership.
11  * The ASF licenses this file to You under the Apache License, Version 2.0
12  * (the "License"); you may not use this file except in compliance with
13  * the License. You may obtain a copy of the License at
14  *
15  * http://www.apache.org/licenses/LICENSE-2.0
16  *
17  * Unless required by applicable law or agreed to in writing, software
18  * distributed under the License is distributed on an "AS IS" BASIS,
19  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
20  * See the License for the specific language governing permissions and
21  * limitations under the License.
22  * ====================================================================
23  *
24  * This software consists of voluntary contributions made by many
25  * individuals on behalf of the Apache Software Foundation. For more
26  * information on the Apache Software Foundation, please see
27  * <http://www.apache.org/>.
28  *
29  */
30
31 package org.apache.commons.httpclient.util;
32 import java.util.ArrayList JavaDoc;
33 import java.util.List JavaDoc;
34
35 import org.apache.commons.httpclient.NameValuePair;
36
37 /**
38  * A simple parser intended to parse sequences of name/value pairs.
39  * Parameter values are exptected to be enclosed in quotes if they
40  * contain unsafe characters, such as '=' characters or separators.
41  * Parameter values are optional and can be omitted.
42  *
43  * <p>
44  * <code>param1 = value; param2 = "anything goes; really"; param3</code>
45  * </p>
46  *
47  * @author <a HREF="mailto:oleg@ural.ru">Oleg Kalnichevski</a>
48  *
49  * @since 3.0
50  */
51 public class ParameterParser {
52     
53     /** String to be parsed */
54     private char[] chars = null;
55     
56     /** Current position in the string */
57     private int pos = 0;
58
59     /** Maximum position in the string */
60     private int len = 0;
61
62     /** Start of a token */
63     private int i1 = 0;
64
65     /** End of a token */
66     private int i2 = 0;
67     
68     /** Default ParameterParser constructor */
69     public ParameterParser() {
70         super();
71     }
72
73
74     /** Are there any characters left to parse? */
75     private boolean hasChar() {
76         return this.pos < this.len;
77     }
78
79     
80     /** A helper method to process the parsed token. */
81     private String JavaDoc getToken(boolean quoted) {
82         // Trim leading white spaces
83 while ((i1 < i2) && (Character.isWhitespace(chars[i1]))) {
84             i1++;
85         }
86         // Trim trailing white spaces
87 while ((i2 > i1) && (Character.isWhitespace(chars[i2 - 1]))) {
88             i2--;
89         }
90         // Strip away quotes if necessary
91 if (quoted) {
92             if (((i2 - i1) >= 2)
93                 && (chars[i1] == '"')
94                 && (chars[i2 - 1] == '"')) {
95                 i1++;
96                 i2--;
97             }
98         }
99         String JavaDoc result = null;
100         if (i2 >= i1) {
101             result = new String JavaDoc(chars, i1, i2 - i1);
102         }
103         return result;
104     }
105
106
107     /** Is given character present in the array of characters? */
108     private boolean isOneOf(char ch, char[] charray) {
109         boolean result = false;
110         for (int i = 0; i < charray.length; i++) {
111             if (ch == charray[i]) {
112                 result = true;
113                 break;
114             }
115         }
116         return result;
117     }
118     
119     
120     /** Parse out a token until any of the given terminators
121      * is encountered. */
122     private String JavaDoc parseToken(final char[] terminators) {
123         char ch;
124         i1 = pos;
125         i2 = pos;
126         while (hasChar()) {
127             ch = chars[pos];
128             if (isOneOf(ch, terminators)) {
129                 break;
130             }
131             i2++;
132             pos++;
133         }
134         return getToken(false);
135     }
136     
137     
138     /** Parse out a token until any of the given terminators
139      * is encountered. Special characters in quoted tokens
140      * are escaped. */
141     private String JavaDoc parseQuotedToken(final char[] terminators) {
142         char ch;
143         i1 = pos;
144         i2 = pos;
145         boolean quoted = false;
146         boolean charEscaped = false;
147         while (hasChar()) {
148             ch = chars[pos];
149             if (!quoted && isOneOf(ch, terminators)) {
150                 break;
151             }
152             if (!charEscaped && ch == '"') {
153                 quoted = !quoted;
154             }
155             charEscaped = (!charEscaped && ch == '\\');
156             i2++;
157             pos++;
158
159         }
160         return getToken(true);
161     }
162     
163     /**
164      * Extracts a list of {@link NameValuePair}s from the given string.
165      *
166      * @param str the string that contains a sequence of name/value pairs
167      * @return a list of {@link NameValuePair}s
168      *
169      */
170     public List JavaDoc parse(final String JavaDoc str, char separator) {
171
172         if (str == null) {
173             return new ArrayList JavaDoc();
174         }
175         return parse(str.toCharArray(), separator);
176     }
177
178     /**
179      * Extracts a list of {@link NameValuePair}s from the given array of
180      * characters.
181      *
182      * @param chars the array of characters that contains a sequence of
183      * name/value pairs
184      *
185      * @return a list of {@link NameValuePair}s
186      */
187     public List JavaDoc parse(final char[] chars, char separator) {
188
189         if (chars == null) {
190             return new ArrayList JavaDoc();
191         }
192         return parse(chars, 0, chars.length, separator);
193     }
194
195
196     /**
197      * Extracts a list of {@link NameValuePair}s from the given array of
198      * characters.
199      *
200      * @param chars the array of characters that contains a sequence of
201      * name/value pairs
202      * @param offset - the initial offset.
203      * @param length - the length.
204      *
205      * @return a list of {@link NameValuePair}s
206      */
207     public List JavaDoc parse(final char[] chars, int offset, int length, char separator) {
208
209         if (chars == null) {
210             return new ArrayList JavaDoc();
211         }
212         List JavaDoc params = new ArrayList JavaDoc();
213         this.chars = chars;
214         this.pos = offset;
215         this.len = length;
216         
217         String JavaDoc paramName = null;
218         String JavaDoc paramValue = null;
219         while (hasChar()) {
220             paramName = parseToken(new char[] {'=', separator});
221             paramValue = null;
222             if (hasChar() && (chars[pos] == '=')) {
223                 pos++; // skip '='
224 paramValue = parseQuotedToken(new char[] {separator});
225             }
226             if (hasChar() && (chars[pos] == separator)) {
227                 pos++; // skip separator
228 }
229             if (paramName != null && !(paramName.equals("") && paramValue == null)) {
230                 params.add(new NameValuePair(paramName, paramValue));
231             }
232         }
233         return params;
234     }
235 }
236
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