Update #0 - First Release

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

@@ -0,0 +1,73 @@
+/*
+ * 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.Comparator;
+
+import com.google.common.annotations.GwtCompatible;
+
+/** An ordering that tries several comparators in order. */
+@GwtCompatible(serializable = true)
+final class CompoundOrdering<T> extends Ordering<T> implements Serializable {
+	final ImmutableList<Comparator<? super T>> comparators;
+
+	CompoundOrdering(Comparator<? super T> primary, Comparator<? super T> secondary) {
+		this.comparators = ImmutableList.<Comparator<? super T>>of(primary, secondary);
+	}
+
+	CompoundOrdering(Iterable<? extends Comparator<? super T>> comparators) {
+		this.comparators = ImmutableList.copyOf(comparators);
+	}
+
+	@Override
+	public int compare(T left, T right) {
+		// Avoid using the Iterator to avoid generating garbage (issue 979).
+		int size = comparators.size();
+		for (int i = 0; i < size; i++) {
+			int result = comparators.get(i).compare(left, right);
+			if (result != 0) {
+				return result;
+			}
+		}
+		return 0;
+	}
+
+	@Override
+	public boolean equals(Object object) {
+		if (object == this) {
+			return true;
+		}
+		if (object instanceof CompoundOrdering) {
+			CompoundOrdering<?> that = (CompoundOrdering<?>) object;
+			return this.comparators.equals(that.comparators);
+		}
+		return false;
+	}
+
+	@Override
+	public int hashCode() {
+		return comparators.hashCode();
+	}
+
+	@Override
+	public String toString() {
+		return "Ordering.compound(" + comparators + ")";
+	}
+
+	private static final long serialVersionUID = 0;
+}