java-design-patterns/double-checked-locking/src/main/java/com/iluwatar/App.java

package com.iluwatar;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 *
 * In Inventory we store the items with a given size. However, we do not store
 * more items than the inventory size. To address concurrent access problems we
 * use double checked locking to add item to inventory. In this method, the
 * thread which gets the lock first adds the item.
 */
public class App {

    public static void main(String[] args) {
        final Inventory inventory = new Inventory(1000);
        ExecutorService executorService = Executors.newFixedThreadPool(3);
        for (int i = 0; i < 3; i++) {
            executorService.execute(new Runnable() {
                @Override
                public void run() {
                    while (inventory.addItem(new Item()));
                }
            });
        }
    }
}