praktikum-holons/src/utility/Pool.java

package utility;

import java.util.ArrayList;
import java.util.stream.Stream;



public abstract class Pool<T> {
	int borrowedCount = 0;
	private int poolCapacity = 1000;
	private ArrayList<T> poolList = new ArrayList<T>(poolCapacity);
	private ArrayList<T> borrowedList = new ArrayList<T>(poolCapacity);
	
	
	public abstract T create();
	
	public Pool(){
		poppulatePool(poolCapacity);
	}
	
	public T get(){
		checkCapacity(borrowedCount);
		T poolObject = poolList.get(borrowedCount);
		borrowedCount++;
		borrowedList.add(poolObject);
		return poolObject;
	}

	public void clear() {
		borrowedList.clear();
		borrowedCount = 0;
	}
	
	
	private void poppulatePool(int amount) {
		for(int i= 0; i < amount; i++) {
			poolList.add(create());
		}
	}

	private void checkCapacity(int requestedCapacity) {
		if(poolCapacity <= requestedCapacity) {
			int newSize = 2 * requestedCapacity;
			poppulatePool(newSize - poolCapacity);	
			poolCapacity = 2*requestedCapacity;
		}
	}
	public int getBorrowedCount() {
		return borrowedCount;
	}
	public Stream<T> getBorrowedStream(){
		return borrowedList.stream();
	}
	
}