1 /**
2 * Licensed to jclouds, Inc. (jclouds) under one or more
3 * contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. jclouds licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 */
19 package org.jclouds.functions;
20
21 import javax.inject.Singleton;
22
23 import com.google.common.base.Function;
24 import com.google.common.collect.Iterables;
25
26 /**
27 * @author Adrian Cole
28 */
29 @Singleton
30 public class OnlyElementOrNull<T> implements Function<Iterable<T>, T> {
31
32 @Override
33 public T apply(Iterable<T> arg0) {
34 if (arg0 == null || Iterables.size(arg0) == 0)
35 return null;
36 return Iterables.getOnlyElement(arg0);
37 }
38 }