Update #0 - First Release

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

@@ -0,0 +1,80 @@
+/*
+ * 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 java.io.Serializable;
+import java.util.Iterator;
+
+import javax.annotation.Nullable;
+
+import com.google.common.annotations.GwtCompatible;
+
+/**
+ * An ordering which sorts iterables by comparing corresponding elements
+ * pairwise.
+ */
+@GwtCompatible(serializable = true)
+final class LexicographicalOrdering<T> extends Ordering<Iterable<T>> implements Serializable {
+	final Ordering<? super T> elementOrder;
+
+	LexicographicalOrdering(Ordering<? super T> elementOrder) {
+		this.elementOrder = elementOrder;
+	}
+
+	@Override
+	public int compare(Iterable<T> leftIterable, Iterable<T> rightIterable) {
+		Iterator<T> left = leftIterable.iterator();
+		Iterator<T> right = rightIterable.iterator();
+		while (left.hasNext()) {
+			if (!right.hasNext()) {
+				return LEFT_IS_GREATER; // because it's longer
+			}
+			int result = elementOrder.compare(left.next(), right.next());
+			if (result != 0) {
+				return result;
+			}
+		}
+		if (right.hasNext()) {
+			return RIGHT_IS_GREATER; // because it's longer
+		}
+		return 0;
+	}
+
+	@Override
+	public boolean equals(@Nullable Object object) {
+		if (object == this) {
+			return true;
+		}
+		if (object instanceof LexicographicalOrdering) {
+			LexicographicalOrdering<?> that = (LexicographicalOrdering<?>) object;
+			return this.elementOrder.equals(that.elementOrder);
+		}
+		return false;
+	}
+
+	@Override
+	public int hashCode() {
+		return elementOrder.hashCode() ^ 2075626741; // meaningless
+	}
+
+	@Override
+	public String toString() {
+		return elementOrder + ".lexicographical()";
+	}
+
+	private static final long serialVersionUID = 0;
+}