/*
    * 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
    *
    *      https://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.commons.lang3.tuple;
  
  import java.util.Objects;
  
  /**
   * A mutable triple consisting of three {@link Object} elements.
   *
   * <p>Not #ThreadSafe#</p>
   *
   * @param <L> the left element type.
   * @param <M> the middle element type.
   * @param <R> the right element type.
   * @since 3.2
   */
  public class MutableTriple<L, M, R> extends Triple<L, M, R> {
  
      /**
       * The empty array singleton.
       * <p>
       * Consider using {@link #emptyArray()} to avoid generics warnings.
       * </p>
       *
       * @since 3.10
       */
      public static final MutableTriple<?, ?, ?>[] EMPTY_ARRAY = {};
  
      /** Serialization version */
      private static final long serialVersionUID = 1L;
  
      /**
       * Returns the empty array singleton that can be assigned without compiler warning.
       *
       * @param <L> the left element type.
       * @param <M> the middle element type.
       * @param <R> the right element type.
       * @return the empty array singleton that can be assigned without compiler warning.
       * @since 3.10
       */
      @SuppressWarnings("unchecked")
      public static <L, M, R> MutableTriple<L, M, R>[] emptyArray() {
          return (MutableTriple<L, M, R>[]) EMPTY_ARRAY;
      }
  
      /**
       * Obtains a mutable triple of three objects inferring the generic types.
       *
       * <p>This factory allows the triple to be created using inference to
       * obtain the generic types.</p>
       *
       * @param <L> the left element type.
       * @param <M> the middle element type.
       * @param <R> the right element type.
       * @param left  the left element, may be null.
       * @param middle  the middle element, may be null.
       * @param right  the right element, may be null.
       * @return a triple formed from the three parameters, not null.
       */
      public static <L, M, R> MutableTriple<L, M, R> of(final L left, final M middle, final R right) {
          return new MutableTriple<>(left, middle, right);
      }
  
      /**
       * Obtains a mutable triple of three non-null objects inferring the generic types.
       *
       * <p>This factory allows the triple to be created using inference to
       * obtain the generic types.</p>
       *
       * @param <L> the left element type.
       * @param <M> the middle element type.
       * @param <R> the right element type.
       * @param left  the left element, may not be null.
       * @param middle  the middle element, may not be null.
       * @param right  the right element, may not be null.
       * @return a triple formed from the three parameters, not null.
       * @throws NullPointerException if any input is null.
       * @since 3.13.0
       */
      public static <L, M, R> MutableTriple<L, M, R> ofNonNull(final L left, final M middle, final R right) {
          return of(Objects.requireNonNull(left, "left"), Objects.requireNonNull(middle, "middle"), Objects.requireNonNull(right, "right"));
      }
  
      /** Left object. */
      public L left;
     /** Middle object. */
     public M middle;
 
     /** Right object. */
     public R right;
 
     /**
      * Create a new triple instance of three nulls.
      */
     public MutableTriple() {
     }
 
     /**
      * Create a new triple instance.
      *
      * @param left  the left value, may be null.
      * @param middle  the middle value, may be null.
      * @param right  the right value, may be null.
      */
     public MutableTriple(final L left, final M middle, final R right) {
         this.left = left;
         this.middle = middle;
         this.right = right;
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public L getLeft() {
         return left;
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public M getMiddle() {
         return middle;
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public R getRight() {
         return right;
     }
 
     /**
      * Sets the left element of the triple.
      *
      * @param left  the new value of the left element, may be null.
      */
     public void setLeft(final L left) {
         this.left = left;
     }
 
     /**
      * Sets the middle element of the triple.
      *
      * @param middle  the new value of the middle element, may be null.
      */
     public void setMiddle(final M middle) {
         this.middle = middle;
     }
 
     /**
      * Sets the right element of the triple.
      *
      * @param right  the new value of the right element, may be null.
      */
     public void setRight(final R right) {
         this.right = right;
     }
 }