EaglerForge/sources/main/java/com/google/common/collect/DescendingMultiset.java

151 lines
3.6 KiB
Java

/*
* Copyright (C) 2012 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.Comparator;
import java.util.Iterator;
import java.util.NavigableSet;
import java.util.Set;
import com.google.common.annotations.GwtCompatible;
/**
* A skeleton implementation of a descending multiset. Only needs
* {@code forwardMultiset()} and {@code entryIterator()}.
*
* @author Louis Wasserman
*/
@GwtCompatible(emulated = true)
abstract class DescendingMultiset<E> extends ForwardingMultiset<E> implements SortedMultiset<E> {
abstract SortedMultiset<E> forwardMultiset();
private transient Comparator<? super E> comparator;
@Override
public Comparator<? super E> comparator() {
Comparator<? super E> result = comparator;
if (result == null) {
return comparator = Ordering.from(forwardMultiset().comparator()).<E>reverse();
}
return result;
}
private transient NavigableSet<E> elementSet;
@Override
public NavigableSet<E> elementSet() {
NavigableSet<E> result = elementSet;
if (result == null) {
return elementSet = new SortedMultisets.NavigableElementSet<E>(this);
}
return result;
}
@Override
public Entry<E> pollFirstEntry() {
return forwardMultiset().pollLastEntry();
}
@Override
public Entry<E> pollLastEntry() {
return forwardMultiset().pollFirstEntry();
}
@Override
public SortedMultiset<E> headMultiset(E toElement, BoundType boundType) {
return forwardMultiset().tailMultiset(toElement, boundType).descendingMultiset();
}
@Override
public SortedMultiset<E> subMultiset(E fromElement, BoundType fromBoundType, E toElement, BoundType toBoundType) {
return forwardMultiset().subMultiset(toElement, toBoundType, fromElement, fromBoundType).descendingMultiset();
}
@Override
public SortedMultiset<E> tailMultiset(E fromElement, BoundType boundType) {
return forwardMultiset().headMultiset(fromElement, boundType).descendingMultiset();
}
@Override
protected Multiset<E> delegate() {
return forwardMultiset();
}
@Override
public SortedMultiset<E> descendingMultiset() {
return forwardMultiset();
}
@Override
public Entry<E> firstEntry() {
return forwardMultiset().lastEntry();
}
@Override
public Entry<E> lastEntry() {
return forwardMultiset().firstEntry();
}
abstract Iterator<Entry<E>> entryIterator();
private transient Set<Entry<E>> entrySet;
@Override
public Set<Entry<E>> entrySet() {
Set<Entry<E>> result = entrySet;
return (result == null) ? entrySet = createEntrySet() : result;
}
Set<Entry<E>> createEntrySet() {
return new Multisets.EntrySet<E>() {
@Override
Multiset<E> multiset() {
return DescendingMultiset.this;
}
@Override
public Iterator<Entry<E>> iterator() {
return entryIterator();
}
@Override
public int size() {
return forwardMultiset().entrySet().size();
}
};
}
@Override
public Iterator<E> iterator() {
return Multisets.iteratorImpl(this);
}
@Override
public Object[] toArray() {
return standardToArray();
}
@Override
public <T> T[] toArray(T[] array) {
return standardToArray(array);
}
@Override
public String toString() {
return entrySet().toString();
}
}