001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.validator.routines;
018
019import java.io.Serializable;
020import java.util.regex.Pattern;
021import java.util.regex.Matcher;
022
023/**
024 * <b>Regular Expression</b> validation (using JDK 1.4+ regex support).
025 * <p>
026 * Construct the validator either for a single regular expression or a set (array) of
027 * regular expressions. By default validation is <i>case sensitive</i> but constructors
028 * are provided to allow  <i>case in-sensitive</i> validation. For example to create
029 * a validator which does <i>case in-sensitive</i> validation for a set of regular
030 * expressions:
031 * </p>
032 * <pre>
033 * <code>
034 * String[] regexs = new String[] {...};
035 * RegexValidator validator = new RegexValidator(regexs, false);
036 * </code>
037 * </pre>
038 *
039 * <ul>
040 *   <li>Validate <code>true</code> or <code>false</code>:</li>
041 *   <li>
042 *     <ul>
043 *       <li><code>boolean valid = validator.isValid(value);</code></li>
044 *     </ul>
045 *   </li>
046 *   <li>Validate returning an aggregated String of the matched groups:</li>
047 *   <li>
048 *     <ul>
049 *       <li><code>String result = validator.validate(value);</code></li>
050 *     </ul>
051 *   </li>
052 *   <li>Validate returning the matched groups:</li>
053 *   <li>
054 *     <ul>
055 *       <li><code>String[] result = validator.match(value);</code></li>
056 *     </ul>
057 *   </li>
058 * </ul>
059 *
060 * <b>Note that patterns are matched against the entire input.</b>
061 *
062 * <p>
063 * Cached instances pre-compile and re-use {@link Pattern}(s) - which according
064 * to the {@link Pattern} API are safe to use in a multi-threaded environment.
065 * </p>
066 *
067 * @version $Revision: 1713331 $
068 * @since Validator 1.4
069 */
070public class RegexValidator implements Serializable {
071
072    private static final long serialVersionUID = -8832409930574867162L;
073
074    private final Pattern[] patterns;
075
076    /**
077     * Construct a <i>case sensitive</i> validator for a single
078     * regular expression.
079     *
080     * @param regex The regular expression this validator will
081     * validate against
082     */
083    public RegexValidator(String regex) {
084        this(regex, true);
085    }
086
087    /**
088     * Construct a validator for a single regular expression
089     * with the specified case sensitivity.
090     *
091     * @param regex The regular expression this validator will
092     * validate against
093     * @param caseSensitive when <code>true</code> matching is <i>case
094     * sensitive</i>, otherwise matching is <i>case in-sensitive</i>
095     */
096    public RegexValidator(String regex, boolean caseSensitive) {
097        this(new String[] {regex}, caseSensitive);
098    }
099
100    /**
101     * Construct a <i>case sensitive</i> validator that matches any one
102     * of the set of regular expressions.
103     *
104     * @param regexs The set of regular expressions this validator will
105     * validate against
106     */
107    public RegexValidator(String[] regexs) {
108        this(regexs, true);
109    }
110
111    /**
112     * Construct a validator that matches any one of the set of regular
113     * expressions with the specified case sensitivity.
114     *
115     * @param regexs The set of regular expressions this validator will
116     * validate against
117     * @param caseSensitive when <code>true</code> matching is <i>case
118     * sensitive</i>, otherwise matching is <i>case in-sensitive</i>
119     */
120    public RegexValidator(String[] regexs, boolean caseSensitive) {
121        if (regexs == null || regexs.length == 0) {
122            throw new IllegalArgumentException("Regular expressions are missing");
123        }
124        patterns = new Pattern[regexs.length];
125        int flags =  (caseSensitive ? 0: Pattern.CASE_INSENSITIVE);
126        for (int i = 0; i < regexs.length; i++) {
127            if (regexs[i] == null || regexs[i].length() == 0) {
128                throw new IllegalArgumentException("Regular expression[" + i + "] is missing");
129            }
130            patterns[i] =  Pattern.compile(regexs[i], flags);
131        }
132    }
133
134    /**
135     * Validate a value against the set of regular expressions.
136     *
137     * @param value The value to validate.
138     * @return <code>true</code> if the value is valid
139     * otherwise <code>false</code>.
140     */
141    public boolean isValid(String value) {
142        if (value == null) {
143            return false;
144        }
145        for (int i = 0; i < patterns.length; i++) {
146            if (patterns[i].matcher(value).matches()) {
147                return true;
148            }
149        }
150        return false;
151    }
152
153    /**
154     * Validate a value against the set of regular expressions
155     * returning the array of matched groups.
156     *
157     * @param value The value to validate.
158     * @return String array of the <i>groups</i> matched if
159     * valid or <code>null</code> if invalid
160     */
161    public String[] match(String value) {
162        if (value == null) {
163            return null;
164        }
165        for (int i = 0; i < patterns.length; i++) {
166            Matcher matcher = patterns[i].matcher(value);
167            if (matcher.matches()) {
168                int count = matcher.groupCount();
169                String[] groups = new String[count];
170                for (int j = 0; j < count; j++) {
171                    groups[j] = matcher.group(j+1);
172                }
173                return groups;
174            }
175        }
176        return null;
177    }
178
179
180    /**
181     * Validate a value against the set of regular expressions
182     * returning a String value of the aggregated groups.
183     *
184     * @param value The value to validate.
185     * @return Aggregated String value comprised of the
186     * <i>groups</i> matched if valid or <code>null</code> if invalid
187     */
188    public String validate(String value) {
189        if (value == null) {
190            return null;
191        }
192        for (int i = 0; i < patterns.length; i++) {
193            Matcher matcher = patterns[i].matcher(value);
194            if (matcher.matches()) {
195                int count = matcher.groupCount();
196                if (count == 1) {
197                    return matcher.group(1);
198                }
199                StringBuilder buffer = new StringBuilder();
200                for (int j = 0; j < count; j++) {
201                    String component = matcher.group(j+1);
202                    if (component != null) {
203                        buffer.append(component);
204                    }
205                }
206                return buffer.toString();
207            }
208        }
209        return null;
210    }
211
212    /**
213     * Provide a String representation of this validator.
214     * @return A String representation of this validator
215     */
216    public String toString() {
217        StringBuilder buffer = new StringBuilder();
218        buffer.append("RegexValidator{");
219        for (int i = 0; i < patterns.length; i++) {
220            if (i > 0) {
221                buffer.append(",");
222            }
223            buffer.append(patterns[i].pattern());
224        }
225        buffer.append("}");
226        return buffer.toString();
227    }
228
229}