content: /**
   * Copyright The Apache Software Foundation
   *
   * 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 com.alibaba.tac.engine.util;
  
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.List;
  
  /**
   * Utility methods for Iterable including null-safe handlers.
   */
  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;
    }
  
  }