/*
* 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 static com.google.common.base.Preconditions.checkNotNull;
import java.util.Comparator;
import javax.annotation.Nullable;
/**
* An empty immutable sorted multiset.
*
* @author Louis Wasserman
*/
final class EmptyImmutableSortedMultiset<E> extends ImmutableSortedMultiset<E> {
EmptyImmutableSortedMultiset(Comparator<? super E> comparator) {
super(comparator);
}
@Override
public Entry<E> firstEntry() {
return null;
}
@Override
public Entry<E> lastEntry() {
return null;
}
@Override
public int count(@Nullable Object element) {
return 0;
}
@Override
public int size() {
return 0;
}
@Override
ImmutableSortedSet<E> createElementSet() {
return ImmutableSortedSet.emptySet(comparator());
}
@Override
ImmutableSortedSet<E> createDescendingElementSet() {
return ImmutableSortedSet.emptySet(reverseComparator());
}
@Override
UnmodifiableIterator<Entry<E>> descendingEntryIterator() {
return Iterators.emptyIterator();
}
@Override
UnmodifiableIterator<Entry<E>> entryIterator() {
return Iterators.emptyIterator();
}
@Override
public ImmutableSortedMultiset<E> headMultiset(E upperBound, BoundType boundType) {
checkNotNull(upperBound);
checkNotNull(boundType);
return this;
}
@Override
public ImmutableSortedMultiset<E> tailMultiset(E lowerBound, BoundType boundType) {
checkNotNull(lowerBound);
checkNotNull(boundType);
return this;
}
@Override
int distinctElements() {
return 0;
}
@Override
boolean isPartialView() {
return false;
}
}
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