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 import javax.annotation.Nullable; 22 23 /** 24 * The result of a {@code BstModifier}. 25 * 26 * @author Louis Wasserman 27 */ 28 @GwtCompatible 29 final class BstModificationResult<N extends BstNode<?, N>> { 30 enum ModificationType { 31 IDENTITY, REBUILDING_CHANGE, REBALANCING_CHANGE; 32 } 33 identity(@ullable N target)34 static <N extends BstNode<?, N>> BstModificationResult<N> identity(@Nullable N target) { 35 return new BstModificationResult<N>(target, target, ModificationType.IDENTITY); 36 } 37 rebuildingChange( @ullable N originalTarget, @Nullable N changedTarget)38 static <N extends BstNode<?, N>> BstModificationResult<N> rebuildingChange( 39 @Nullable N originalTarget, @Nullable N changedTarget) { 40 return new BstModificationResult<N>( 41 originalTarget, changedTarget, ModificationType.REBUILDING_CHANGE); 42 } 43 rebalancingChange( @ullable N originalTarget, @Nullable N changedTarget)44 static <N extends BstNode<?, N>> BstModificationResult<N> rebalancingChange( 45 @Nullable N originalTarget, @Nullable N changedTarget) { 46 return new BstModificationResult<N>( 47 originalTarget, changedTarget, ModificationType.REBALANCING_CHANGE); 48 } 49 50 @Nullable private final N originalTarget; 51 @Nullable private final N changedTarget; 52 private final ModificationType type; 53 BstModificationResult( @ullable N originalTarget, @Nullable N changedTarget, ModificationType type)54 private BstModificationResult( 55 @Nullable N originalTarget, @Nullable N changedTarget, ModificationType type) { 56 this.originalTarget = originalTarget; 57 this.changedTarget = changedTarget; 58 this.type = checkNotNull(type); 59 } 60 61 @Nullable getOriginalTarget()62 N getOriginalTarget() { 63 return originalTarget; 64 } 65 66 @Nullable getChangedTarget()67 N getChangedTarget() { 68 return changedTarget; 69 } 70 getType()71 ModificationType getType() { 72 return type; 73 } 74 } 75