/*
* Copyright 2013, 2014 Deutsche Nationalbibliothek
*
* 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.culturegraph.mf.metamorph.functions;
/**
* Only outputs the received value if it is whitelisted.
*
* @author Markus Michael Geipel
*/
public final class WhiteList extends AbstractLookup {
@Override
public String process(final String key) {
final String returnValue = lookup(key);
if (returnValue != null) {
return key;
}
return null;
}
}