Initial Jack import.

Change-Id: I953cf0a520195a7187d791b2885848ad0d5a9b43

1 files changed, 78 insertions, 0 deletions

diff --git a/guava/src/com/google/common/collect/ExplicitOrdering.java b/guava/src/com/google/common/collect/ExplicitOrdering.java
new file mode 100644
index 0000000..0a2e181
--- /dev/null
+++ b/guava/src/com/google/common/collect/ExplicitOrdering.java
@@ -0,0 +1,78 @@
+/*
+ * Copyright (C) 2007 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 com.google.common.annotations.GwtCompatible;
+
+import java.io.Serializable;
+import java.util.List;
+
+import javax.annotation.Nullable;
+
+/** An ordering that compares objects according to a given order. */
+@GwtCompatible(serializable = true)
+final class ExplicitOrdering<T> extends Ordering<T> implements Serializable {
+  final ImmutableMap<T, Integer> rankMap;
+
+  ExplicitOrdering(List<T> valuesInOrder) {
+    this(buildRankMap(valuesInOrder));
+  }
+
+  ExplicitOrdering(ImmutableMap<T, Integer> rankMap) {
+    this.rankMap = rankMap;
+  }
+
+  @Override public int compare(T left, T right) {
+    return rank(left) - rank(right); // safe because both are nonnegative
+  }
+
+  private int rank(T value) {
+    Integer rank = rankMap.get(value);
+    if (rank == null) {
+      throw new IncomparableValueException(value);
+    }
+    return rank;
+  }
+
+  private static <T> ImmutableMap<T, Integer> buildRankMap(
+      List<T> valuesInOrder) {
+    ImmutableMap.Builder<T, Integer> builder = ImmutableMap.builder();
+    int rank = 0;
+    for (T value : valuesInOrder) {
+      builder.put(value, rank++);
+    }
+    return builder.build();
+  }
+
+  @Override public boolean equals(@Nullable Object object) {
+    if (object instanceof ExplicitOrdering) {
+      ExplicitOrdering<?> that = (ExplicitOrdering<?>) object;
+      return this.rankMap.equals(that.rankMap);
+    }
+    return false;
+  }
+
+  @Override public int hashCode() {
+    return rankMap.hashCode();
+  }
+
+  @Override public String toString() {
+    return "Ordering.explicit(" + rankMap.keySet() + ")";
+  }
+
+  private static final long serialVersionUID = 0;
+}