code: /*
   * Copyright (c) 2019 the Eclipse Milo Authors
   *
   * This program and the accompanying materials are made
   * available under the terms of the Eclipse Public License 2.0
   * which is available at https://www.eclipse.org/legal/epl-2.0/
   *
   * SPDX-License-Identifier: EPL-2.0
   */
  
  package org.eclipse.milo.opcua.stack.core.util;
  
  import java.lang.reflect.Array;
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.List;
  import java.util.stream.Stream;
  
  public class ConversionUtil {
  
      @SuppressWarnings("unchecked")
      public static <T> T[] toArray(List<T> list, Class<T> c) {
          Object array = Array.newInstance(c, list.size());
          for (int i = 0; i < list.size(); i++) {
              Array.set(array, i, list.get(i));
          }
          return (T[]) array;
      }
  
      public static <T> List<T> toList(T[] array) {
          return array != null ? Arrays.asList(array) : Collections.emptyList();
      }
  
      public static <T> Stream<T> toStream(T[] array) {
          return array != null ? Arrays.stream(array) : Stream.empty();
      }
  
      public static <T> T[] a(List<T> list, Class<T> c) {
          return toArray(list, c);
      }
  
      public static <T> List<T> l(T[] array) {
          return toList(array);
      }
  
      public static <T> Stream<T> s(T[] array) {
          return toStream(array);
      }
  
  }
  