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.openstreetmap.josm.data.validation.routines;
018
019import java.util.regex.Matcher;
020import java.util.regex.Pattern;
021
022/**
023 * <b>Regular Expression</b> validation (using JDK 1.4+ regex support).
024 * <p>
025 * Construct the validator either for a single regular expression or a set (array) of
026 * regular expressions. By default validation is <i>case sensitive</i> but constructors
027 * are provided to allow  <i>case in-sensitive</i> validation. For example to create
028 * a validator which does <i>case in-sensitive</i> validation for a set of regular
029 * expressions:
030 * </p>
031 * <pre>
032 * <code>
033 * String[] regexs = new String[] {...};
034 * RegexValidator validator = new RegexValidator(regexs, false);
035 * </code>
036 * </pre>
037 *
038 * <ul>
039 *   <li>Validate <code>true</code> or <code>false</code>:</li>
040 *   <li>
041 *     <ul>
042 *       <li><code>boolean valid = validator.isValid(value);</code></li>
043 *     </ul>
044 *   </li>
045 *   <li>Validate returning an aggregated String of the matched groups:</li>
046 *   <li>
047 *     <ul>
048 *       <li><code>String result = validator.validate(value);</code></li>
049 *     </ul>
050 *   </li>
051 *   <li>Validate returning the matched groups:</li>
052 *   <li>
053 *     <ul>
054 *       <li><code>String[] result = validator.match(value);</code></li>
055 *     </ul>
056 *   </li>
057 * </ul>
058 *
059 * <b>Note that patterns are matched against the entire input.</b>
060 *
061 * <p>
062 * Cached instances pre-compile and re-use {@link Pattern}(s) - which according
063 * to the {@link Pattern} API are safe to use in a multi-threaded environment.
064 * </p>
065 *
066 * @version $Revision: 1741724 $
067 * @since Validator 1.4
068 */
069public class RegexValidator extends AbstractValidator {
070
071    private final Pattern[] patterns;
072
073    /**
074     * Construct a <i>case sensitive</i> validator for a single
075     * regular expression.
076     *
077     * @param regex The regular expression this validator will
078     * validate against
079     */
080    public RegexValidator(String regex) {
081        this(regex, true);
082    }
083
084    /**
085     * Construct a validator for a single regular expression
086     * with the specified case sensitivity.
087     *
088     * @param regex The regular expression this validator will
089     * validate against
090     * @param caseSensitive when <code>true</code> matching is <i>case
091     * sensitive</i>, otherwise matching is <i>case in-sensitive</i>
092     */
093    public RegexValidator(String regex, boolean caseSensitive) {
094        this(new String[] {regex}, caseSensitive);
095    }
096
097    /**
098     * Construct a <i>case sensitive</i> validator that matches any one
099     * of the set of regular expressions.
100     *
101     * @param regexs The set of regular expressions this validator will
102     * validate against
103     */
104    public RegexValidator(String... regexs) {
105        this(regexs, true);
106    }
107
108    /**
109     * Construct a validator that matches any one of the set of regular
110     * expressions with the specified case sensitivity.
111     *
112     * @param regexs The set of regular expressions this validator will
113     * validate against
114     * @param caseSensitive when <code>true</code> matching is <i>case
115     * sensitive</i>, otherwise matching is <i>case in-sensitive</i>
116     */
117    public RegexValidator(String[] regexs, boolean caseSensitive) {
118        if (regexs == null || regexs.length == 0) {
119            throw new IllegalArgumentException("Regular expressions are missing");
120        }
121        patterns = new Pattern[regexs.length];
122        int flags = caseSensitive ? 0 : Pattern.CASE_INSENSITIVE;
123        for (int i = 0; i < regexs.length; i++) {
124            if (regexs[i] == null || regexs[i].isEmpty()) {
125                throw new IllegalArgumentException("Regular expression[" + i + "] is missing");
126            }
127            patterns[i] = Pattern.compile(regexs[i], flags);
128        }
129    }
130
131    /**
132     * Validate a value against the set of regular expressions.
133     *
134     * @param value The value to validate.
135     * @return <code>true</code> if the value is valid
136     * otherwise <code>false</code>.
137     */
138    @Override
139    public boolean isValid(String value) {
140        if (value == null) {
141            return false;
142        }
143        for (int i = 0; i < patterns.length; i++) {
144            if (patterns[i].matcher(value).matches()) {
145                return true;
146            }
147        }
148        return false;
149    }
150
151    @Override
152    public String getValidatorName() {
153        return null;
154    }
155
156    /**
157     * Validate a value against the set of regular expressions
158     * returning the array of matched groups.
159     *
160     * @param value The value to validate.
161     * @return String array of the <i>groups</i> matched if
162     * valid or <code>null</code> if invalid
163     */
164    public String[] match(String value) {
165        if (value == null) {
166            return null;
167        }
168        for (int i = 0; i < patterns.length; i++) {
169            Matcher matcher = patterns[i].matcher(value);
170            if (matcher.matches()) {
171                int count = matcher.groupCount();
172                String[] groups = new String[count];
173                for (int j = 0; j < count; j++) {
174                    groups[j] = matcher.group(j+1);
175                }
176                return groups;
177            }
178        }
179        return null;
180    }
181
182    /**
183     * Validate a value against the set of regular expressions
184     * returning a String value of the aggregated groups.
185     *
186     * @param value The value to validate.
187     * @return Aggregated String value comprised of the
188     * <i>groups</i> matched if valid or <code>null</code> if invalid
189     */
190    public String validate(String value) {
191        if (value == null) {
192            return null;
193        }
194        for (int i = 0; i < patterns.length; i++) {
195            Matcher matcher = patterns[i].matcher(value);
196            if (matcher.matches()) {
197                int count = matcher.groupCount();
198                if (count == 1) {
199                    return matcher.group(1);
200                }
201                StringBuilder buffer = new StringBuilder();
202                for (int j = 0; j < count; j++) {
203                    String component = matcher.group(j+1);
204                    if (component != null) {
205                        buffer.append(component);
206                    }
207                }
208                return buffer.toString();
209            }
210        }
211        return null;
212    }
213
214    /**
215     * Provide a String representation of this validator.
216     * @return A String representation of this validator
217     */
218    @Override
219    public String toString() {
220        StringBuilder buffer = new StringBuilder(32);
221        buffer.append("RegexValidator{");
222        for (int i = 0; i < patterns.length; i++) {
223            if (i > 0) {
224                buffer.append(',');
225            }
226            buffer.append(patterns[i].pattern());
227        }
228        buffer.append('}');
229        return buffer.toString();
230    }
231}