/**
 * Licensed to jclouds, Inc. (jclouds) under one or more
 * contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  jclouds 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.jclouds.functions;

import javax.inject.Singleton;

import com.google.common.base.Function;
import com.google.common.collect.Iterables;

/**
 * @author Adrian Cole
 */
@Singleton
public class OnlyElementOrNull<T> implements Function<Iterable<T>, T> {

   @Override
   public T apply(Iterable<T> arg0) {
      if (arg0 == null || Iterables.size(arg0) == 0)
         return null;
      return Iterables.getOnlyElement(arg0);
   }
}