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diff --git a/guava/src/com/google/common/collect/BstMutationRule.java b/guava/src/com/google/common/collect/BstMutationRule.java
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+++ b/guava/src/com/google/common/collect/BstMutationRule.java
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+/*
+ * Copyright (C) 2011 The Guava Authors
+ *
+ * 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.common.collect;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+import com.google.common.annotations.GwtCompatible;
+
+/**
+ * A rule for a local mutation to a binary search tree, that changes at most one entry. In addition
+ * to specifying how it modifies a particular entry via a {@code BstModifier}, it specifies a
+ * {@link BstBalancePolicy} for rebalancing the tree after the modification is performed and a
+ * {@link BstNodeFactory} for constructing newly rebalanced nodes.
+ *
+ * @author Louis Wasserman
+ * @param <K> The key type of the nodes in binary search trees that this rule can modify.
+ * @param <N> The type of the nodes in binary search trees that this rule can modify.
+ */
+@GwtCompatible
+final class BstMutationRule<K, N extends BstNode<K, N>> {
+  /**
+   * Constructs a {@code BstMutationRule} with the specified modifier, balance policy, and node
+   * factory.
+   */
+  public static <K, N extends BstNode<K, N>> BstMutationRule<K, N> createRule(
+      BstModifier<K, N> modifier, BstBalancePolicy<N> balancePolicy,
+      BstNodeFactory<N> nodeFactory) {
+    return new BstMutationRule<K, N>(modifier, balancePolicy, nodeFactory);
+  }
+
+  private final BstModifier<K, N> modifier;
+  private final BstBalancePolicy<N> balancePolicy;
+  private final BstNodeFactory<N> nodeFactory;
+
+  private BstMutationRule(BstModifier<K, N> modifier, BstBalancePolicy<N> balancePolicy,
+      BstNodeFactory<N> nodeFactory) {
+    this.balancePolicy = checkNotNull(balancePolicy);
+    this.nodeFactory = checkNotNull(nodeFactory);
+    this.modifier = checkNotNull(modifier);
+  }
+
+  /**
+   * Returns the {@link BstModifier} that specifies the change to a targeted entry in a binary
+   * search tree.
+   */
+  public BstModifier<K, N> getModifier() {
+    return modifier;
+  }
+
+  /**
+   * Returns the policy used to rebalance nodes in the tree after this modification has been
+   * performed.
+   */
+  public BstBalancePolicy<N> getBalancePolicy() {
+    return balancePolicy;
+  }
+
+  /**
+   * Returns the node factory used to create new nodes in the tree after this modification has been
+   * performed.
+   */
+  public BstNodeFactory<N> getNodeFactory() {
+    return nodeFactory;
+  }
+}