    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.List;
    021import java.util.regex.Matcher;
    022import java.util.regex.Pattern;
    023
    024/**
    025 * <b>Regular Expression</b> validation (using the JRE's regular expression support).
    026 * <p>
    027 * Constructs the validator either for a single regular expression or a set (array) of
    028 * regular expressions. By default validation is <i>case sensitive</i> but constructors
    029 * are provided to allow  <i>case in-sensitive</i> validation. For example to create
    030 * a validator which does <i>case in-sensitive</i> validation for a set of regular
    031 * expressions:
    032 * </p>
    033 * <pre>
    034 * <code>
    035 * String[] regexs = new String[] {...};
    036 * RegexValidator validator = new RegexValidator(regexs, false);
    037 * </code>
    038 * </pre>
    039 *
    040 * <ul>
    041 *   <li>Validate {@code true} or {@code false}:</li>
    042 *   <li>
    043 *     <ul>
    044 *       <li><code>boolean valid = validator.isValid(value);</code></li>
    045 *     </ul>
    046 *   </li>
    047 *   <li>Validate returning an aggregated String of the matched groups:</li>
    048 *   <li>
    049 *     <ul>
    050 *       <li><code>String result = validator.validate(value);</code></li>
    051 *     </ul>
    052 *   </li>
    053 *   <li>Validate returning the matched groups:</li>
    054 *   <li>
    055 *     <ul>
    056 *       <li><code>String[] result = validator.match(value);</code></li>
    057 *     </ul>
    058 *   </li>
    059 * </ul>
    060 *
    061 * <b>Note that patterns are matched against the entire input.</b>
    062 *
    063 * <p>
    064 * Cached instances pre-compile and re-use {@link Pattern}(s) - which according
    065 * to the {@link Pattern} API are safe to use in a multi-threaded environment.
    066 * </p>
    067 *
    068 * @since 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     * Constructs a <i>case sensitive</i> validator that matches any one
    078     * in the list of regular expressions.
    079     *
    080     * @param regexs The set of regular expressions this validator will
    081     * validate against
    082     */
    083    RegexValidator(final List<String> regexs) {
    084        this(regexs.toArray(new String[] {}), true);
    085    }
    086
    087    /**
    088     * Constructs a <i>case sensitive</i> validator for a single
    089     * regular expression.
    090     *
    091     * @param regex The regular expression this validator will
    092     * validate against
    093     */
    094    public RegexValidator(final String regex) {
    095        this(regex, true);
    096    }
    097
    098    /**
    099     * Constructs a <i>case sensitive</i> validator that matches any one
    100     * in the array of regular expressions.
    101     *
    102     * @param regexs The set of regular expressions this validator will
    103     * validate against
    104     */
    105    public RegexValidator(final String... regexs) {
    106        this(regexs, true);
    107    }
    108
    109    /**
    110     * Constructs a validator for a single regular expression
    111     * with the specified case sensitivity.
    112     *
    113     * @param regex The regular expression this validator will
    114     * validate against
    115     * @param caseSensitive when {@code true} matching is <i>case
    116     * sensitive</i>, otherwise matching is <i>case in-sensitive</i>
    117     */
    118    public RegexValidator(final String regex, final boolean caseSensitive) {
    119        this(new String[] { regex }, caseSensitive);
    120    }
    121
    122    /**
    123     * Constructs a validator that matches any one of the set of regular
    124     * expressions with the specified case sensitivity.
    125     *
    126     * @param regexs The set of regular expressions this validator will
    127     * validate against
    128     * @param caseSensitive when {@code true} matching is <i>case
    129     * sensitive</i>, otherwise matching is <i>case in-sensitive</i>
    130     */
    131    public RegexValidator(final String[] regexs, final boolean caseSensitive) {
    132        if (regexs == null || regexs.length == 0) {
    133            throw new IllegalArgumentException("Regular expressions are missing");
    134        }
    135        patterns = new Pattern[regexs.length];
    136        final int flags = caseSensitive ? 0 : Pattern.CASE_INSENSITIVE;
    137        for (int i = 0; i < regexs.length; i++) {
    138            if (regexs[i] == null || regexs[i].isEmpty()) {
    139                throw new IllegalArgumentException("Regular expression[" + i + "] is missing");
    140            }
    141            patterns[i] = Pattern.compile(regexs[i], flags);
    142        }
    143    }
    144
    145    /**
    146     * Gets a copy of the Patterns.
    147     *
    148     * @return a copy of the Patterns.
    149     * @since 1.8
    150     */
    151    public Pattern[] getPatterns() {
    152        return patterns.clone();
    153    }
    154
    155    /**
    156     * Validates a value against the set of regular expressions.
    157     *
    158     * @param value The value to validate.
    159     * @return {@code true} if the value is valid
    160     * otherwise {@code false}.
    161     */
    162    public boolean isValid(final String value) {
    163        if (value == null) {
    164            return false;
    165        }
    166        for (final Pattern pattern : patterns) {
    167            if (pattern.matcher(value).matches()) {
    168                return true;
    169            }
    170        }
    171        return false;
    172    }
    173
    174    /**
    175     * Validates a value against the set of regular expressions
    176     * returning the array of matched groups.
    177     *
    178     * @param value The value to validate.
    179     * @return String array of the <i>groups</i> matched if
    180     * valid or <code>null</code> if invalid
    181     */
    182    public String[] match(final String value) {
    183        if (value == null) {
    184            return null;
    185        }
    186        for (final Pattern pattern : patterns) {
    187            final Matcher matcher = pattern.matcher(value);
    188            if (matcher.matches()) {
    189                final int count = matcher.groupCount();
    190                final String[] groups = new String[count];
    191                for (int j = 0; j < count; j++) {
    192                    groups[j] = matcher.group(j + 1);
    193                }
    194                return groups;
    195            }
    196        }
    197        return null;
    198    }
    199
    200    /**
    201     * Provides a String representation of this validator.
    202     * @return A String representation of this validator.
    203     */
    204    @Override
    205    public String toString() {
    206        final StringBuilder buffer = new StringBuilder();
    207        buffer.append("RegexValidator{");
    208        for (int i = 0; i < patterns.length; i++) {
    209            if (i > 0) {
    210                buffer.append(",");
    211            }
    212            buffer.append(patterns[i].pattern());
    213        }
    214        buffer.append("}");
    215        return buffer.toString();
    216    }
    217
    218    /**
    219     * Validates a value against the set of regular expressions
    220     * returning a String value of the aggregated groups.
    221     *
    222     * @param value The value to validate.
    223     * @return Aggregated String value comprised of the
    224     * <i>groups</i> matched if valid or <code>null</code> if invalid
    225     */
    226    public String validate(final String value) {
    227        if (value == null) {
    228            return null;
    229        }
    230        for (final Pattern pattern : patterns) {
    231            final Matcher matcher = pattern.matcher(value);
    232            if (matcher.matches()) {
    233                final int count = matcher.groupCount();
    234                if (count == 1) {
    235                    return matcher.group(1);
    236                }
    237                final StringBuilder buffer = new StringBuilder();
    238                for (int j = 0; j < count; j++) {
    239                    final String component = matcher.group(j + 1);
    240                    if (component != null) {
    241                        buffer.append(component);
    242                    }
    243                }
    244                return buffer.toString();
    245            }
    246        }
    247        return null;
    248    }
    249
    250}