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feilong is a suite of core and expanded libraries that include utility classes, http, excel,cvs, io classes, and much much more.
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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.feilong.lib.validator;

import java.io.Serializable;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * Regular Expression validation (using JDK 1.4+ regex support).
 * 
 * Construct the validator either for a single regular expression or a set (array) of
 * regular expressions. By default validation is case sensitive but constructors
 * are provided to allow case in-sensitive validation. For example to create
 * a validator which does case in-sensitive validation for a set of regular
 * expressions:
 * 
 * 
 *  * 
 * String[] regexs = new String[] {...};
 * RegexValidator validator = new RegexValidator(regexs, false);
 * 
 * 
 *
 * 
 * Validate true or false:
 * 
 * 
 * boolean valid = validator.isValid(value);
 * 
 * 
 * Validate returning an aggregated String of the matched groups:
 * 
 * 
 * String result = validator.validate(value);
 * 
 * 
 * Validate returning the matched groups:
 * 
 * 
 * String[] result = validator.match(value);
 * 
 * 
 * 
 *
 * Note that patterns are matched against the entire input.
 *
 * 
 * Cached instances pre-compile and re-use {@link Pattern}(s) - which according
 * to the {@link Pattern} API are safe to use in a multi-threaded environment.
 * 
 *
 * @version $Revision: 1739356 $
 * @since Validator 1.4
 */
public class RegexValidator implements Serializable{

    private static final long serialVersionUID = -8832409930574867162L;

    private final Pattern[]   patterns;

    /**
     * Construct a case sensitive validator for a single
     * regular expression.
     *
     * @param regex
     *            The regular expression this validator will
     *            validate against
     */
    public RegexValidator(String regex){
        this(new String[] { regex }, true);
    }

    /**
     * Construct a validator that matches any one of the set of regular
     * expressions with the specified case sensitivity.
     *
     * @param regexs
     *            The set of regular expressions this validator will
     *            validate against
     * @param caseSensitive
     *            when true matching is case
     *            sensitive, otherwise matching is case in-sensitive
     */
    public RegexValidator(String[] regexs, boolean caseSensitive){
        if (regexs == null || regexs.length == 0){
            throw new IllegalArgumentException("Regular expressions are missing");
        }
        patterns = new Pattern[regexs.length];
        int flags = (caseSensitive ? 0 : Pattern.CASE_INSENSITIVE);
        for (int i = 0; i < regexs.length; i++){
            if (regexs[i] == null || regexs[i].length() == 0){
                throw new IllegalArgumentException("Regular expression[" + i + "] is missing");
            }
            patterns[i] = Pattern.compile(regexs[i], flags);
        }
    }

    /**
     * Validate a value against the set of regular expressions.
     *
     * @param value
     *            The value to validate.
     * @return true if the value is valid
     *         otherwise false.
     */
    public boolean isValid(String value){
        if (value == null){
            return false;
        }
        for (Pattern pattern : patterns){
            if (pattern.matcher(value).matches()){
                return true;
            }
        }
        return false;
    }

    /**
     * Validate a value against the set of regular expressions
     * returning the array of matched groups.
     *
     * @param value
     *            The value to validate.
     * @return String array of the groups matched if
     *         valid or null if invalid
     */
    public String[] match(String value){
        if (value == null){
            return null;
        }
        for (Pattern pattern : patterns){
            Matcher matcher = pattern.matcher(value);
            if (matcher.matches()){
                int count = matcher.groupCount();
                String[] groups = new String[count];
                for (int j = 0; j < count; j++){
                    groups[j] = matcher.group(j + 1);
                }
                return groups;
            }
        }
        return null;
    }

    /**
     * Provide a String representation of this validator.
     * 
     * @return A String representation of this validator
     */
    @Override
    public String toString(){
        StringBuilder buffer = new StringBuilder();
        buffer.append("RegexValidator{");
        for (int i = 0; i < patterns.length; i++){
            if (i > 0){
                buffer.append(",");
            }
            buffer.append(patterns[i].pattern());
        }
        buffer.append("}");
        return buffer.toString();
    }

}