1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF 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, software
13 * distributed under the License is distributed on an "AS IS" BASIS,
14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 * See the License for the specific language governing permissions and
16 * limitations under the License.
17 */
18
19 package org.apache.hadoop.hbase.util;
20
21 import java.util.ArrayList;
22 import java.util.Collections;
23 import java.util.List;
24
25 import org.apache.hadoop.hbase.classification.InterfaceAudience;
26
27 /**
28 * Utility methods for Iterable including null-safe handlers.
29 */
30 @InterfaceAudience.Private
31 public class IterableUtils {
32
33 private static final List<Object> EMPTY_LIST = Collections
34 .unmodifiableList(new ArrayList<Object>(0));
35
36 @SuppressWarnings("unchecked")
37 public static <T> Iterable<T> nullSafe(Iterable<T> in) {
38 if (in == null) {
39 return (List<T>) EMPTY_LIST;
40 }
41 return in;
42 }
43
44 }