NullTransform.java

/*
 * ====================
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 *
 * Copyright 2008-2009 Sun Microsystems, Inc. All rights reserved.
 *
 * The contents of this file are subject to the terms of the Common Development
 * and Distribution License("CDDL") (the "License").  You may not use this file
 * except in compliance with the License.
 *
 * You can obtain a copy of the License at
 * http://opensource.org/licenses/cddl1.php
 * See the License for the specific language governing permissions and limitations
 * under the License.
 *
 * When distributing the Covered Code, include this CDDL Header Notice in each file
 * and include the License file at http://opensource.org/licenses/cddl1.php.
 * If applicable, add the following below this CDDL Header, with the fields
 * enclosed by brackets [] replaced by your own identifying information:
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 * ====================
 */
package org.identityconnectors.patternparser;

import java.util.regex.Pattern;

import org.w3c.dom.Element;

/**
 * A NullTransform specifies a string to be used in a match. If the input
 * matches the pattern, a null is returned, otherwise the input is returned.
 */
public class NullTransform extends Transform<Object> {
    private static final String PATTERN = "pattern";
    private Pattern pattern;

    protected String getAttributes() {
        return super.getAttributes() + attributeToString(PATTERN, pattern.pattern());
    }

    /**
     * Create a NullTransform from an Element.
     *
     * @param element
     */
    public NullTransform(Element element) {
        this(element.getAttribute(PATTERN));
    }

    /**
     * Create a NullTransform using the <b>pattern<b>.
     *
     * @param pattern
     *            a pattern to be replaced.
     */
    public NullTransform(String pattern) {
        this.pattern = Pattern.compile(pattern);
    }

    /**
     * Convert <b>input</b> into a String, and match it against <b>pattern</b>,
     * returning a null if the match is successful.
     *
     * @param input
     *            the object to be transformed
     * @return null, or the input
     */
    @Override
    public Object transform(Object input) throws Exception {
        if (pattern.matcher(input.toString()).matches()) {
            return null;
        } else {
            return input;
        }
    }
}