1 /* 2 * Copyright (C) 2011 The Guava Authors 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except 5 * in compliance with the License. You may obtain a copy of the License at 6 * 7 * http://www.apache.org/licenses/LICENSE-2.0 8 * 9 * Unless required by applicable law or agreed to in writing, software distributed under the 10 * License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either 11 * express or implied. See the License for the specific language governing permissions and 12 * limitations under the License. 13 */ 14 15 package com.google.common.collect; 16 17 import static com.google.common.base.Preconditions.checkNotNull; 18 19 import com.google.common.annotations.GwtCompatible; 20 21 /** 22 * A rule for a local mutation to a binary search tree, that changes at most one entry. In addition 23 * to specifying how it modifies a particular entry via a {@code BstModifier}, it specifies a 24 * {@link BstBalancePolicy} for rebalancing the tree after the modification is performed and a 25 * {@link BstNodeFactory} for constructing newly rebalanced nodes. 26 * 27 * @author Louis Wasserman 28 * @param <K> The key type of the nodes in binary search trees that this rule can modify. 29 * @param <N> The type of the nodes in binary search trees that this rule can modify. 30 */ 31 @GwtCompatible 32 final class BstMutationRule<K, N extends BstNode<K, N>> { 33 /** 34 * Constructs a {@code BstMutationRule} with the specified modifier, balance policy, and node 35 * factory. 36 */ 37 public static <K, N extends BstNode<K, N>> BstMutationRule<K, N> createRule( 38 BstModifier<K, N> modifier, BstBalancePolicy<N> balancePolicy, 39 BstNodeFactory<N> nodeFactory) { 40 return new BstMutationRule<K, N>(modifier, balancePolicy, nodeFactory); 41 } 42 43 private final BstModifier<K, N> modifier; 44 private final BstBalancePolicy<N> balancePolicy; 45 private final BstNodeFactory<N> nodeFactory; 46 47 private BstMutationRule(BstModifier<K, N> modifier, BstBalancePolicy<N> balancePolicy, 48 BstNodeFactory<N> nodeFactory) { 49 this.balancePolicy = checkNotNull(balancePolicy); 50 this.nodeFactory = checkNotNull(nodeFactory); 51 this.modifier = checkNotNull(modifier); 52 } 53 54 /** 55 * Returns the {@link BstModifier} that specifies the change to a targeted entry in a binary 56 * search tree. 57 */ 58 public BstModifier<K, N> getModifier() { 59 return modifier; 60 } 61 62 /** 63 * Returns the policy used to rebalance nodes in the tree after this modification has been 64 * performed. 65 */ 66 public BstBalancePolicy<N> getBalancePolicy() { 67 return balancePolicy; 68 } 69 70 /** 71 * Returns the node factory used to create new nodes in the tree after this modification has been 72 * performed. 73 */ 74 public BstNodeFactory<N> getNodeFactory() { 75 return nodeFactory; 76 } 77 } 78
