TreeHeap.java Source code

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Here is the source code for TreeHeap.java

Source

//package opennlp.tools.util;

import java.util.Iterator;
import java.util.SortedSet;
import java.util.TreeSet;

/** 
 * An implementation of the Heap interface based on {@link java.util.SortedSet}.
 * This implementation will not allow multiple objects which are equal to be added to the heap.
 * Only use this implementation when object in the heap can be totally ordered (no duplicates). 
 */
public class TreeHeap implements Heap {

    private SortedSet tree;

    /** 
     * Creates a new tree heap.
     */
    public TreeHeap() {
        tree = new TreeSet();
    }

    /**
     * Creates a new tree heap of the specified size.
     * @param size The size of the new tree heap.
     */
    public TreeHeap(int size) {
        tree = new TreeSet();
    }

    public Object extract() {
        Object rv = tree.first();
        tree.remove(rv);
        return rv;
    }

    public Object first() {
        return tree.first();
    }

    public Object last() {
        return tree.last();
    }

    public Iterator iterator() {
        return tree.iterator();
    }

    public void add(Object o) {
        tree.add(o);
    }

    public int size() {
        return tree.size();
    }

    public void clear() {
        tree.clear();
    }

    public boolean isEmpty() {
        return this.tree.isEmpty();
    }

    public static void main(String[] args) {
        Heap heap = new TreeHeap(5);
        for (int ai = 0; ai < args.length; ai++) {
            heap.add(Integer.valueOf(Integer.parseInt(args[ai])));
        }
        while (!heap.isEmpty()) {
            System.out.print(heap.extract() + " ");
        }
        System.out.println();
    }

}

///////////////////////////////////////////////////////////////////////////////
//Copyright (C) 2003 Thomas Morton
// 
//This library is free software; you can redistribute it and/or
//modify it under the terms of the GNU Lesser General Public
//License as published by the Free Software Foundation; either
//version 2.1 of the License, or (at your option) any later version.
// 
//This library is distributed in the hope that it will be useful,
//but WITHOUT ANY WARRANTY; without even the implied warranty of
//MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//GNU Lesser General Public License for more details.
// 
//You should have received a copy of the GNU Lesser General Public
//License along with this program; if not, write to the Free Software
//Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
//////////////////////////////////////////////////////////////////////////////

/** Interface for interacting with a Heap data structure.  
 * This implementation extract objects from smallest to largest based on either
 * their natural ordering or the comparator provided to an implementation.
 * While this is a typical of a heap it allows this objects natural ordering to
 * match that of other sorted collections.
 * */
interface Heap {

    /** 
     * Removes the smallest element from the heap and returns it.
     * @return The smallest element from the heap.
     */
    public Object extract();

    /**
     * Returns the smallest element of the heap.
     * @return The top element of the heap.
     */
    public Object first();

    /**
     * Returns the largest element of the heap.
     * @return The largest element of the heap.
     */
    public Object last();

    /**
     * Adds the specified object to the heap.
     * @param o The object to add to the heap.
     */
    public void add(Object o);

    /**
     * Returns the size of the heap.
     * @return The size of the heap.
     */
    public int size();

    /**
     * Returns whether the heap is empty.
     * @return true if the heap is empty; false otherwise.
     */
    public boolean isEmpty();

    /**
     * Returns an iterator over the elements of the heap.  No specific ordering of these 
     * elements is guaranteed. 
     * @return An iterator over the elements of the heap.
     */
    public Iterator iterator();

    /**
     * Clears the contents of the heap.
     */
    public void clear();

}