/*

 * Copyright 2010 Werner Guttmann

 *

 * Licensed 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 org.exolab.castor.util;



import java.util.regex.Pattern;

import java.util.regex.PatternSyntaxException;



/**

 * An implementation of {@link RegExpEvaluator} that uses the Java Regular

 * Expression library.

 * 

 * @author <a href="mailto:george76@hotmail.com">George Varghese</a>

 * @since 1.3.2

 **/

public class SunRegExpEvaluator implements RegExpEvaluator {



    /**

     * The Regular expression

     **/

    private Pattern _pattern;



    /**

     * Sets the regular expression to match against during a call to #matches

     * 

     * @param rexpr

     *            the regular expression

     **/

    public void setExpression(String rexpr) {



        if (rexpr != null) {

            try {

                // -- patch and compile expression

                _pattern = Pattern.compile(rexpr);

            } catch (PatternSyntaxException ex) {

                String err = "RegExp Syntax error: ";

                err += ex.getMessage();

                err += " ; error occured with the following "

                        + "regular expression: " + rexpr;



                throw new IllegalArgumentException(err, ex);

            }

        }

    }



    /**

     * Returns true if the given String is matched by the regular expression of

     * this RegExpEvaluator

     * 

     * @param value

     *            the String to check the production of

     * @return true if the given string matches the regular expression of this

     *         RegExpEvaluator

     * @see #setExpression

     **/

    public boolean matches(String value) {

        if (_pattern != null) {

            return _pattern.matcher(value).matches();

        }

        return true;

    }



}