/*
* 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 com.google.common.annotations.GwtCompatible;
import java.util.Collection;
import java.util.Comparator;
import java.util.Iterator;
import java.util.SortedSet;
/**
* A {@link Multiset} which maintains the ordering of its elements, according to
* either their natural order or an explicit {@link Comparator}. In all cases,
* this implementation uses {@link Comparable#compareTo} or
* {@link Comparator#compare} instead of {@link Object#equals} to determine
* equivalence of instances.
*
* <p><b>Warning:</b> The comparison must be <i>consistent with equals</i> as
* explained by the {@link Comparable} class specification. Otherwise, the
* resulting multiset will violate the {@link Collection} contract, which it is
* specified in terms of {@link Object#equals}.
*
* @author Louis Wasserman
*/
@GwtCompatible interface SortedMultiset<E>
extends Multiset<E>, SortedIterable<E> {
/**
* Returns the comparator that orders this multiset, or
* {@link Ordering#natural()} if the natural ordering of the elements is used.
*/
Comparator<? super E> comparator();
/**
* Returns the entry of the first element in this multiset, or {@code null} if
* this multiset is empty.
*/
Entry<E> firstEntry();
/**
* Returns the entry of the last element in this multiset, or {@code null} if
* this multiset is empty.
*/
Entry<E> lastEntry();
/**
* Returns and removes the entry associated with the lowest element in this
* multiset, or returns {@code null} if this multiset is empty.
*/
Entry<E> pollFirstEntry();
/**
* Returns and removes the entry associated with the greatest element in this
* multiset, or returns {@code null} if this multiset is empty.
*/
Entry<E> pollLastEntry();
/**
* Returns a {@link SortedSet} view of the distinct elements in this multiset.
*/
@Override SortedSet<E> elementSet();
/**
* {@inheritDoc}
*
* <p>The iterator returns the elements in ascending order according to this
* multiset's comparator.
*/
@Override Iterator<E> iterator();
/**
* Returns a descending view of this multiset. Modifications made to either
* map will be reflected in the other.
*/
SortedMultiset<E> descendingMultiset();
/**
* Returns a view of this multiset restricted to the elements less than
* {@code upperBound}, optionally including {@code upperBound} itself. The
* returned multiset is a view of this multiset, so changes to one will be
* reflected in the other. The returned multiset supports all operations that
* this multiset supports.
*
* <p>The returned multiset will throw an {@link IllegalArgumentException} on
* attempts to add elements outside its range.
*/
SortedMultiset<E> headMultiset(E upperBound, BoundType boundType);
/**
* Returns a view of this multiset restricted to the range between
* {@code lowerBound} and {@code upperBound}. The returned multiset is a view
* of this multiset, so changes to one will be reflected in the other. The
* returned multiset supports all operations that this multiset supports.
*
* <p>The returned multiset will throw an {@link IllegalArgumentException} on
* attempts to add elements outside its range.
*
* <p>This method is equivalent to
* {@code tailMultiset(lowerBound, lowerBoundType).headMultiset(upperBound,
* upperBoundType)}.
*/
SortedMultiset<E> subMultiset(E lowerBound, BoundType lowerBoundType,
E upperBound, BoundType upperBoundType);
/**
* Returns a view of this multiset restricted to the elements greater than
* {@code lowerBound}, optionally including {@code lowerBound} itself. The
* returned multiset is a view of this multiset, so changes to one will be
* reflected in the other. The returned multiset supports all operations that
* this multiset supports.
*
* <p>The returned multiset will throw an {@link IllegalArgumentException} on
* attempts to add elements outside its range.
*/
SortedMultiset<E> tailMultiset(E lowerBound, BoundType boundType);
}
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