/**
* Copyright 2001 Jean-Francois Doue
*
* This file is part of Asteroid Zone. Asteroid Zone is free software;
* you can redistribute it and/or modify it under the terms of the
* GNU General Public License as published by the Free Software Foundation;
* either version 2 of the License, or (at your option) any later version.
* Asteroid Zone 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 General Public License for more details.
* You should have received a copy of the GNU General Public License
* along with Asteroid Zone; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place, Suite 330,
* Boston, MA 02111-1307 USA
*/
package asteroids;
/**
* Class to implement efficient, pool based collections.
* The class supports an iterator method for collection traversal,
* and methods to add and remove elements. The collection size
* cannot grow beyond the size of the initial pool of objects
* provided for the collection.
* @author Jean-Francois Doue
* @version 1.1, 2001/10/02
*/
public class Pool extends Object {
/**
* An object array the pool where objects are actually stored.
*/
public Object[] pool;
/**
* The number of objects currently in the pool.
*/
public int count;
/**
* The index of the current object.
*/
public int current;
/**
* Initializes the collection with a pool of instances.
*/
public Pool(Object[] pool) {
this.pool = pool;
}
/**
* Resets the collection iterator.
*/
public final void reset() {
current = count - 1;
}
/**
* Returns the next object in the collection.
*/
public final Object next() {
if (current >= 0) {
return pool[current--];
}
return null;
}
/**
* Removes the current object from the collection.
*/
public final void removeCurrent() {
if (current + 1 < count - 1) {
Object tmp = pool[current + 1];
pool[current + 1] = pool[count - 1];
pool[count - 1] = tmp;
}
count--;
}
/**
* Adds a new object to the collection. The
* returned object must be initialized by the callee.
* Returns null if the collection capacity has been
* exceeded.
*/
public final Object addNewObject() {
if (count >= pool.length) {
return null;
}
return pool[count++];
}
/**
* Removes all the objects from the collection.
*/
public final void removeAll() {
count = 0;
}
/**
* Returns the size of the collection.
*/
public final int size() {
return count;
}
}