/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF 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.apache.hadoop.hbase.util;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import org.apache.hadoop.classification.InterfaceAudience;

/**
 * Utility methods for Iterable including null-safe handlers.
 */
@InterfaceAudience.Private
public class IterableUtils {

  private static final List<Object> EMPTY_LIST = Collections
      .unmodifiableList(new ArrayList<Object>(0));

  @SuppressWarnings("unchecked")
  public static <T> Iterable<T> nullSafe(Iterable<T> in) {
    if (in == null) {
      return (List<T>) EMPTY_LIST;
    }
    return in;
  }

}
