/*
 * 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.tsfile.external.commons.lang3.tuple;

import java.util.Objects;

/////////////////////////////////////////////////////////////////////////////////////////////////
// IoTDB
/////////////////////////////////////////////////////////////////////////////////////////////////

/**
 * An immutable triple consisting of three {@link Object} elements.
 *
 * <p>Although the implementation is immutable, there is no restriction on the objects that may be
 * stored. If mutable objects are stored in the triple, then the triple itself effectively becomes
 * mutable.
 *
 * <p>#ThreadSafe# if all three objects are thread-safe.
 *
 * @param <L> the left element type.
 * @param <M> the middle element type.
 * @param <R> the right element type.
 * @since 3.2
 */
public class ImmutableTriple<L, M, R> extends Triple<L, M, R> {

  /**
   * An empty array.
   *
   * <p>Consider using {@link #emptyArray()} to avoid generics warnings.
   *
   * @since 3.10
   */
  public static final ImmutableTriple<?, ?, ?>[] EMPTY_ARRAY = {};

  /** An immutable triple of nulls. */
  // This is not defined with generics to avoid warnings in call sites.
  @SuppressWarnings("rawtypes")
  private static final ImmutableTriple NULL = new ImmutableTriple<>(null, null, null);

  /** Serialization version. */
  private static final long serialVersionUID = 1L;

  /**
   * Gets 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> ImmutableTriple<L, M, R>[] emptyArray() {
    return (ImmutableTriple<L, M, R>[]) EMPTY_ARRAY;
  }

  /**
   * Gets the immutable triple of nulls singleton.
   *
   * @param <L> the left element of this triple. Value is {@code null}.
   * @param <M> the middle element of this triple. Value is {@code null}.
   * @param <R> the right element of this triple. Value is {@code null}.
   * @return an immutable triple of nulls.
   * @since 3.6
   */
  @SuppressWarnings("unchecked")
  public static <L, M, R> ImmutableTriple<L, M, R> nullTriple() {
    return NULL;
  }

  /**
   * Creates an immutable triple of three objects inferring the generic types.
   *
   * <p>This factory allows the triple to be created using inference to obtain the generic types.
   *
   * @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> ImmutableTriple<L, M, R> of(final L left, final M middle, final R right) {
    return left != null | middle != null || right != null
        ? new ImmutableTriple<>(left, middle, right)
        : nullTriple();
  }

  /**
   * Creates an immutable 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.
   *
   * @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> ImmutableTriple<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 final L left;

  /** Middle object. */
  public final M middle;

  /** Right object. */
  public final R right;

  /**
   * Constructs 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 ImmutableTriple(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;
  }
}
