trunk/bval-core/src/main/java/org/apache/bval/routines/EMailValidationUtils.java

/*
 *  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 org.apache.bval.routines;

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

/**
 * Description: holds the regexp to validate an email address<br>
 * User: roman.stumm<br>
 * Date: 17.06.2010<br>
 * Time: 10:40:59<br>
 */
public class EMailValidationUtils {
    private static String ATOM = "[^\\x00-\\x1F^\\(^\\)^\\<^\\>^\\@^\\,^\\;^\\:^\\\\^\\\"^\\.^\\[^\\]^\\s]";
    private static String DOMAIN = "(" + ATOM + "+(\\." + ATOM + "+)*";
    private static String IP_DOMAIN = "\\[[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\]";
    public static final java.util.regex.Pattern DEFAULT_EMAIL_PATTERN;

    static {
        DEFAULT_EMAIL_PATTERN =
            java.util.regex.Pattern.compile("^" + ATOM + "+(\\." + ATOM + "+)*@" + DOMAIN + "|" + IP_DOMAIN + ")$",
                java.util.regex.Pattern.CASE_INSENSITIVE);
    }

    /**
     * Learn whether a given object is a valid email address.
     * 
     * @param value
     *            to check
     * @return <code>true</code> if the validation passes
     */
    public static boolean isValid(Object value) {
        return isValid(value, DEFAULT_EMAIL_PATTERN);
    }

    /**
     * Learn whether a particular value matches a given pattern per
     * {@link Matcher#matches()}.
     * 
     * @param value
     * @param aPattern
     * @return <code>true</code> if <code>value</code> was a <code>String</code>
     *         matching <code>aPattern</code>
     */
    // TODO it would seem to make sense to move or reduce the visibility of this
    // method as it is more general than email.
    public static boolean isValid(Object value, Pattern aPattern) {
        if (value == null)
            return true;
        if (!(value instanceof CharSequence))
            return false;
        CharSequence seq = (CharSequence) value;
        if (seq.length() == 0)
            return true;
        Matcher m = aPattern.matcher(seq);
        return m.matches();
    }

}