package safeluck.drive.evaluation.cEventCenter;

/**
 * 自定义的对象池
 * MyApplication2
 * Created by lzw on 2019/12/30. 17:06:49
 * 邮箱：632393724@qq.com
 * All Rights Saved! Chongqing AnYun Tech co. LTD
 */
public abstract class ObjectPool<T extends PooledObject> {
    /**
     *  对象容器
     */
    private T[] mContainer;

    /**
     *  对象锁
     */
    private final Object LOCK = new Object();

    /***
     * 每次返回对象都放到数据末端，length表示前面可用对象数
     */
    private int length;

    public ObjectPool(int capacity) {
        mContainer = createObjPool(capacity);
    }

    /**
     * 创建对象池
     * @param capacity 最大限度容量
     * @return
     */
    protected abstract T[] createObjPool(int capacity) ;

    /**
     * 创建一个新的对象
     * @return
     */
    protected abstract T createNewObj();


    public final T get(){
        //先从池中找到空闲的对象，如果没有，则重新创建一个对象
        T obj = findFreeObject();
        if (null == obj){
            obj = createNewObj();
        }else{
            obj.reset();
        }
        return obj;
    }

    /**
     * 从池中找到空闲的对象
     * @return
     */
    private T findFreeObject() {
        T obj = null;
        synchronized (LOCK){
            if (length > 0 ){
                --length;
                obj = mContainer[length];
                //赋值完成后释放资源
                mContainer[length] = null;
            }
        }
        return obj;
    }

    /**
     * 把对象放回池里面
     * @param obj
     */
    public final void returnObj(T obj){
        synchronized (LOCK){
            int size = mContainer.length;
            if (length < size){
                mContainer[length] = obj;
                length++;
            }
        }
    }
}