org.hsqldb.lib.HsqlHeap Maven / Gradle / Ivy
Show all versions of hsqldb Show documentation
/* Copyright (c) 2001-2019, The HSQL Development Group
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* Neither the name of the HSQL Development Group nor the names of its
* contributors may be used to endorse or promote products derived from this
* software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL HSQL DEVELOPMENT GROUP, HSQLDB.ORG,
* OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.hsqldb.lib;
/**
* Provides the base HSQLDB interface for Heap ADT implementations.
*
* In this context, a Heap is simply a collection-like ADT that allows addition
* of elements and provides a way to remove the least element, given some
* implementation-dependent strategy for imposing an order over its
* elements.
*
* Typically, an HsqlHeap will be implemented as a tree-like structure that
* recursively guarantees a Heap Invariant, such that all nodes below
* the root are greater than the root, given some comparison strategy.
* This in turn provides the basis for an efficient implementation of ADTs such
* PriorityQueue, since Heap operations using the typical implementation are,
* in theory, guaranteed to be O(log n).
*
* @author Campbell Burnet (campbell-burnet@users dot sourceforge.net)
* @version 1.7.2
* @since 1.7.2
*/
public interface HsqlHeap {
/**
* Removes all of the elements from this Heap.
*/
void clear();
/**
* Retrieves whether this Heap is empty.
*/
boolean isEmpty();
/**
* Retrieves whether this Heap is full.
*/
boolean isFull();
/**
* Adds the specified element to this Heap.
*
* @param o The element to add
* @throws IllegalArgumentException if the implementation does
* not accept elements of the supplied type (optional)
* throws RuntimeException if the implementation
* dictates that this Heap is not currently accepting additions
* or that this Heap is currently full (optional)
*/
void add(Object o) throws IllegalArgumentException, RuntimeException;
/**
* Retrieves the least element from this Heap, without removing it.
*
* @return the least element from this Heap
*/
Object peek();
/**
* Retrieves the least element from this Heap, removing it in the process.
*
* @return the least element from this Heap
*/
Object remove();
/**
* Retrieves the number of elements currently in this Heap.
*
* @return the number of elements currently in this Heap
*/
int size();
}