com.google.firebase.database.collection.LLRBEmptyNode Maven / Gradle / Ivy

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/*
 * Copyright 2017 Google Inc.
 *
 * Licensed 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.google.firebase.database.collection;

import java.util.Comparator;

public class LLRBEmptyNode implements LLRBNode {

  private static final LLRBEmptyNode INSTANCE = new LLRBEmptyNode();

  private LLRBEmptyNode() {}

  @SuppressWarnings("unchecked")
  public static  LLRBEmptyNode getInstance() {
    return INSTANCE;
  }

  @Override
  public LLRBNode copy(
      K key, V value, Color color, LLRBNode left, LLRBNode right) {
    return this;
  }

  @Override
  public LLRBNode insert(K key, V value, Comparator comparator) {
    return new LLRBRedValueNode<>(key, value);
  }

  @Override
  public LLRBNode remove(K key, Comparator comparator) {
    return this;
  }

  @Override
  public boolean isEmpty() {
    return true;
  }

  @Override
  public boolean isRed() {
    return false;
  }

  @Override
  public K getKey() {
    return null;
  }

  @Override
  public V getValue() {
    return null;
  }

  @Override
  public LLRBNode getLeft() {
    return this;
  }

  @Override
  public LLRBNode getRight() {
    return this;
  }

  @Override
  public LLRBNode getMin() {
    return this;
  }

  @Override
  public LLRBNode getMax() {
    return this;
  }

  @Override
  public int count() {
    return 0;
  }

  @Override
  public void inOrderTraversal(NodeVisitor visitor) {
    // No-op
  }

  @Override
  public boolean shortCircuitingInOrderTraversal(ShortCircuitingNodeVisitor visitor) {
    // No-op
    return true;
  }

  @Override
  public boolean shortCircuitingReverseOrderTraversal(ShortCircuitingNodeVisitor visitor) {
    // No-op
    return true;
  }
}