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 com.google.common.annotations.GwtCompatible; 18 19 import javax.annotation.Nullable; 20 21 /** 22 * A factory for copying nodes in binary search trees with different children. 23 * 24 * <p>Typically, nodes will carry more information than the fields in the {@link BstNode} class, 25 * often some kind of value or some aggregate data for the subtree. This factory is responsible for 26 * copying this additional data between nodes. 27 * 28 * @author Louis Wasserman 29 * @param <N> The type of the tree nodes constructed with this {@code BstNodeFactory}. 30 */ 31 @GwtCompatible 32 abstract class BstNodeFactory<N extends BstNode<?, N>> { 33 /** 34 * Returns a new {@code N} with the key and value data from {@code source}, with left child 35 * {@code left}, and right child {@code right}. If {@code left} or {@code right} is null, the 36 * returned node will not have a child on the corresponding side. 37 */ 38 public abstract N createNode(N source, @Nullable N left, @Nullable N right); 39 40 /** 41 * Returns a new {@code N} with the key and value data from {@code source} that is a leaf. 42 */ 43 public final N createLeaf(N source) { 44 return createNode(source, null, null); 45 } 46 } 47
