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 * <pre>
031 *         String[] regexs = new String[] {...};
032 *         RegexValidator validator = new RegexValidator(regexs, false);
033 * </pre>
034 * <p>
035 * <ul>
036 *   <li>Validate <code>true</code> or <code>false</code>:
037 *   <ul>
038 *     <li><code>boolean valid = validator.isValid(value);</code></li>
039 *   </ul></li>
040 *   <li>Validate returning an aggregated String of the matched groups:
041 *   <ul>
042 *     <li><code>String result = validator.validate(value);</code></li>
043 *   </ul></li>
044 *   <li>Validate returning the matched groups:
045 *   <ul>
046 *     <li><code>String[] result = validator.match(value);</code></li>
047 *   </ul></li>
048 * </ul>
049 * <p>
050 * Cached instances pre-compile and re-use {@link Pattern}(s) - which according
051 * to the {@link Pattern} API are safe to use in a multi-threaded environment.
052 *
053 * @version $Revision: 1227719 $ $Date: 2012-01-05 18:45:51 +0100 (Thu, 05 Jan 2012) $
054 * @since Validator 1.4
055 */
056public class RegexValidator extends AbstractValidator {
057
058    private final Pattern[] patterns;
059
060    /**
061     * Construct a <i>case sensitive</i> validator for a single
062     * regular expression.
063     *
064     * @param regex The regular expression this validator will
065     * validate against
066     */
067    public RegexValidator(String regex) {
068        this(regex, true);
069    }
070
071    /**
072     * Construct a validator for a single regular expression
073     * with the specified case sensitivity.
074     *
075     * @param regex The regular expression this validator will
076     * validate against
077     * @param caseSensitive when <code>true</code> matching is <i>case
078     * sensitive</i>, otherwise matching is <i>case in-sensitive</i>
079     */
080    public RegexValidator(String regex, boolean caseSensitive) {
081        this(new String[] {regex}, caseSensitive);
082    }
083
084    /**
085     * Construct a <i>case sensitive</i> validator that matches any one
086     * of the set of regular expressions.
087     *
088     * @param regexs The set of regular expressions this validator will
089     * validate against
090     */
091    public RegexValidator(String[] regexs) {
092        this(regexs, true);
093    }
094
095    /**
096     * Construct a validator that matches any one of the set of regular
097     * expressions with the specified case sensitivity.
098     *
099     * @param regexs The set of regular expressions this validator will
100     * validate against
101     * @param caseSensitive when <code>true</code> matching is <i>case
102     * sensitive</i>, otherwise matching is <i>case in-sensitive</i>
103     */
104    public RegexValidator(String[] regexs, boolean caseSensitive) {
105        if (regexs == null || regexs.length == 0) {
106            throw new IllegalArgumentException("Regular expressions are missing");
107        }
108        patterns = new Pattern[regexs.length];
109        int flags = caseSensitive ? 0 : Pattern.CASE_INSENSITIVE;
110        for (int i = 0; i < regexs.length; i++) {
111            if (regexs[i] == null || regexs[i].isEmpty()) {
112                throw new IllegalArgumentException("Regular expression[" + i + "] is missing");
113            }
114            patterns[i] =  Pattern.compile(regexs[i], flags);
115        }
116    }
117
118    /**
119     * Validate a value against the set of regular expressions.
120     *
121     * @param value The value to validate.
122     * @return <code>true</code> if the value is valid
123     * otherwise <code>false</code>.
124     */
125    @Override
126    public boolean isValid(String value) {
127        if (value == null) {
128            return false;
129        }
130        for (int i = 0; i < patterns.length; i++) {
131            if (patterns[i].matcher(value).matches()) {
132                return true;
133            }
134        }
135        return false;
136    }
137
138    /**
139     * Validate a value against the set of regular expressions
140     * returning the array of matched groups.
141     *
142     * @param value The value to validate.
143     * @return String array of the <i>groups</i> matched if
144     * valid or <code>null</code> if invalid
145     */
146    public String[] match(String value) {
147        if (value == null) {
148            return null;
149        }
150        for (int i = 0; i < patterns.length; i++) {
151            Matcher matcher = patterns[i].matcher(value);
152            if (matcher.matches()) {
153                int count = matcher.groupCount();
154                String[] groups = new String[count];
155                for (int j = 0; j < count; j++) {
156                    groups[j] = matcher.group(j+1);
157                }
158                return groups;
159            }
160        }
161        return null;
162    }
163
164
165    /**
166     * Validate a value against the set of regular expressions
167     * returning a String value of the aggregated groups.
168     *
169     * @param value The value to validate.
170     * @return Aggregated String value comprised of the
171     * <i>groups</i> matched if valid or <code>null</code> if invalid
172     */
173    public String validate(String value) {
174        if (value == null) {
175            return null;
176        }
177        for (int i = 0; i < patterns.length; i++) {
178            Matcher matcher = patterns[i].matcher(value);
179            if (matcher.matches()) {
180                int count = matcher.groupCount();
181                if (count == 1) {
182                    return matcher.group(1);
183                }
184                StringBuilder buffer = new StringBuilder();
185                for (int j = 0; j < count; j++) {
186                    String component = matcher.group(j+1);
187                    if (component != null) {
188                        buffer.append(component);
189                    }
190                }
191                return buffer.toString();
192            }
193        }
194        return null;
195    }
196
197    /**
198     * Provide a String representation of this validator.
199     * @return A String representation of this validator
200     */
201    @Override
202    public String toString() {
203        StringBuilder buffer = new StringBuilder();
204        buffer.append("RegexValidator{");
205        for (int i = 0; i < patterns.length; i++) {
206            if (i > 0) {
207                buffer.append(',');
208            }
209            buffer.append(patterns[i].pattern());
210        }
211        buffer.append('}');
212        return buffer.toString();
213    }
214}