    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 $Revision$
    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    @Override
    217    public String toString() {
    218        StringBuilder buffer = new StringBuilder();
    219        buffer.append("RegexValidator{");
    220        for (int i = 0; i < patterns.length; i++) {
    221            if (i > 0) {
    222                buffer.append(",");
    223            }
    224            buffer.append(patterns[i].pattern());
    225        }
    226        buffer.append("}");
    227        return buffer.toString();
    228    }
    229
    230}