Update #0 - First Release

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

@@ -0,0 +1,107 @@
+/*
+ * 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.util.Collection;
+import java.util.Set;
+
+import javax.annotation.Nullable;
+
+import com.google.common.annotations.GwtCompatible;
+
+/**
+ * An empty immutable set.
+ *
+ * @author Kevin Bourrillion
+ */
+@GwtCompatible(serializable = true, emulated = true)
+final class EmptyImmutableSet extends ImmutableSet<Object> {
+	static final EmptyImmutableSet INSTANCE = new EmptyImmutableSet();
+
+	private EmptyImmutableSet() {
+	}
+
+	@Override
+	public int size() {
+		return 0;
+	}
+
+	@Override
+	public boolean isEmpty() {
+		return true;
+	}
+
+	@Override
+	public boolean contains(@Nullable Object target) {
+		return false;
+	}
+
+	@Override
+	public boolean containsAll(Collection<?> targets) {
+		return targets.isEmpty();
+	}
+
+	@Override
+	public UnmodifiableIterator<Object> iterator() {
+		return Iterators.emptyIterator();
+	}
+
+	@Override
+	boolean isPartialView() {
+		return false;
+	}
+
+	@Override
+	int copyIntoArray(Object[] dst, int offset) {
+		return offset;
+	}
+
+	@Override
+	public ImmutableList<Object> asList() {
+		return ImmutableList.of();
+	}
+
+	@Override
+	public boolean equals(@Nullable Object object) {
+		if (object instanceof Set) {
+			Set<?> that = (Set<?>) object;
+			return that.isEmpty();
+		}
+		return false;
+	}
+
+	@Override
+	public final int hashCode() {
+		return 0;
+	}
+
+	@Override
+	boolean isHashCodeFast() {
+		return true;
+	}
+
+	@Override
+	public String toString() {
+		return "[]";
+	}
+
+	Object readResolve() {
+		return INSTANCE; // preserve singleton property
+	}
+
+	private static final long serialVersionUID = 0;
+}