Update #0 - First Release

sources/main/java/com/google/common/collect/ReverseNaturalOrdering.java

@@ -0,0 +1,103 @@
+/*
+ * 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 static com.google.common.base.Preconditions.checkNotNull;
+
+import java.io.Serializable;
+import java.util.Iterator;
+
+import com.google.common.annotations.GwtCompatible;
+
+/** An ordering that uses the reverse of the natural order of the values. */
+@GwtCompatible(serializable = true)
+@SuppressWarnings("unchecked") // TODO(kevinb): the right way to explain this??
+final class ReverseNaturalOrdering extends Ordering<Comparable> implements Serializable {
+	static final ReverseNaturalOrdering INSTANCE = new ReverseNaturalOrdering();
+
+	@Override
+	public int compare(Comparable left, Comparable right) {
+		checkNotNull(left); // right null is caught later
+		if (left == right) {
+			return 0;
+		}
+
+		return right.compareTo(left);
+	}
+
+	@Override
+	public <S extends Comparable> Ordering<S> reverse() {
+		return Ordering.natural();
+	}
+
+	// Override the min/max methods to "hoist" delegation outside loops
+
+	@Override
+	public <E extends Comparable> E min(E a, E b) {
+		return NaturalOrdering.INSTANCE.max(a, b);
+	}
+
+	@Override
+	public <E extends Comparable> E min(E a, E b, E c, E... rest) {
+		return NaturalOrdering.INSTANCE.max(a, b, c, rest);
+	}
+
+	@Override
+	public <E extends Comparable> E min(Iterator<E> iterator) {
+		return NaturalOrdering.INSTANCE.max(iterator);
+	}
+
+	@Override
+	public <E extends Comparable> E min(Iterable<E> iterable) {
+		return NaturalOrdering.INSTANCE.max(iterable);
+	}
+
+	@Override
+	public <E extends Comparable> E max(E a, E b) {
+		return NaturalOrdering.INSTANCE.min(a, b);
+	}
+
+	@Override
+	public <E extends Comparable> E max(E a, E b, E c, E... rest) {
+		return NaturalOrdering.INSTANCE.min(a, b, c, rest);
+	}
+
+	@Override
+	public <E extends Comparable> E max(Iterator<E> iterator) {
+		return NaturalOrdering.INSTANCE.min(iterator);
+	}
+
+	@Override
+	public <E extends Comparable> E max(Iterable<E> iterable) {
+		return NaturalOrdering.INSTANCE.min(iterable);
+	}
+
+	// preserving singleton-ness gives equals()/hashCode() for free
+	private Object readResolve() {
+		return INSTANCE;
+	}
+
+	@Override
+	public String toString() {
+		return "Ordering.natural().reverse()";
+	}
+
+	private ReverseNaturalOrdering() {
+	}
+
+	private static final long serialVersionUID = 0;
+}