Update #0 - First Release

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

@@ -0,0 +1,158 @@
+/*
+ * Copyright (C) 2011 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.NoSuchElementException;
+import java.util.Set;
+
+import javax.annotation.Nullable;
+
+import com.google.common.annotations.GwtCompatible;
+import com.google.common.annotations.GwtIncompatible;
+
+/**
+ * An empty contiguous set.
+ *
+ * @author Gregory Kick
+ */
+@GwtCompatible(emulated = true)
+@SuppressWarnings("unchecked") // allow ungenerified Comparable types
+final class EmptyContiguousSet<C extends Comparable> extends ContiguousSet<C> {
+	EmptyContiguousSet(DiscreteDomain<C> domain) {
+		super(domain);
+	}
+
+	@Override
+	public C first() {
+		throw new NoSuchElementException();
+	}
+
+	@Override
+	public C last() {
+		throw new NoSuchElementException();
+	}
+
+	@Override
+	public int size() {
+		return 0;
+	}
+
+	@Override
+	public ContiguousSet<C> intersection(ContiguousSet<C> other) {
+		return this;
+	}
+
+	@Override
+	public Range<C> range() {
+		throw new NoSuchElementException();
+	}
+
+	@Override
+	public Range<C> range(BoundType lowerBoundType, BoundType upperBoundType) {
+		throw new NoSuchElementException();
+	}
+
+	@Override
+	ContiguousSet<C> headSetImpl(C toElement, boolean inclusive) {
+		return this;
+	}
+
+	@Override
+	ContiguousSet<C> subSetImpl(C fromElement, boolean fromInclusive, C toElement, boolean toInclusive) {
+		return this;
+	}
+
+	@Override
+	ContiguousSet<C> tailSetImpl(C fromElement, boolean fromInclusive) {
+		return this;
+	}
+
+	@GwtIncompatible("not used by GWT emulation")
+	@Override
+	int indexOf(Object target) {
+		return -1;
+	}
+
+	@Override
+	public UnmodifiableIterator<C> iterator() {
+		return Iterators.emptyIterator();
+	}
+
+	@GwtIncompatible("NavigableSet")
+	@Override
+	public UnmodifiableIterator<C> descendingIterator() {
+		return Iterators.emptyIterator();
+	}
+
+	@Override
+	boolean isPartialView() {
+		return false;
+	}
+
+	@Override
+	public boolean isEmpty() {
+		return true;
+	}
+
+	@Override
+	public ImmutableList<C> asList() {
+		return ImmutableList.of();
+	}
+
+	@Override
+	public String toString() {
+		return "[]";
+	}
+
+	@Override
+	public boolean equals(@Nullable Object object) {
+		if (object instanceof Set) {
+			Set<?> that = (Set<?>) object;
+			return that.isEmpty();
+		}
+		return false;
+	}
+
+	@Override
+	public int hashCode() {
+		return 0;
+	}
+
+	@GwtIncompatible("serialization")
+	private static final class SerializedForm<C extends Comparable> implements Serializable {
+		private final DiscreteDomain<C> domain;
+
+		private SerializedForm(DiscreteDomain<C> domain) {
+			this.domain = domain;
+		}
+
+		private Object readResolve() {
+			return new EmptyContiguousSet<C>(domain);
+		}
+
+		private static final long serialVersionUID = 0;
+	}
+
+	@GwtIncompatible("serialization")
+	@Override
+	Object writeReplace() {
+		return new SerializedForm<C>(domain);
+	}
+
+	@GwtIncompatible("NavigableSet")
+	ImmutableSortedSet<C> createDescendingSet() {
+		return new EmptyImmutableSortedSet<C>(Ordering.natural().reverse());
+	}
+}