package com.taobao.tddl.config.impl;

import java.util.List;
import java.util.concurrent.Executor;

import com.taobao.tddl.common.exception.TddlException;
import com.taobao.tddl.common.utils.TStringUtil;
import com.taobao.tddl.config.ConfigDataListener;
import com.taobao.tddl.config.impl.holder.ConfigHolderFactory;

import com.taobao.tddl.common.utils.logger.Logger;
import com.taobao.tddl.common.utils.logger.LoggerFactory;

/**
 * 使用delegate模式，引入Preheat机制，允许预先构建cache，加速请求处理
 * 
 * @author jianghang 2013-10-28 下午7:36:03
 * @since 5.0.0
 */
public class PreheatDataHandler extends UnitConfigDataHandler {

    private static final Logger   logger = LoggerFactory.getLogger(PreheatDataHandler.class);
    private UnitConfigDataHandler delagate;

    @Override
    public void doInit() throws TddlException {
        delagate = loadHandlerExtension();
        // 做一下数据预热
        if (delagate.initialData == null && ConfigHolderFactory.isInit(delagate.getAppName())) {
            delagate.initialData = ConfigHolderFactory.getConfigDataHolder(delagate.getAppName()).getData(dataId);
        }

        delagate.init();
    }

    @Override
    public String getData(long timeout, String strategy) {
        if (ConfigHolderFactory.isInit(delagate.getAppName())) {
            String result = ConfigHolderFactory.getConfigDataHolder(delagate.getAppName()).getData(dataId);
            if (!TStringUtil.isEmpty(result)) {
                return result;
            }
            logger.error("PreheatDataHandler Miss Data, Use Default Handler. DataId Is : " + dataId);
        }

        return delagate.getData(timeout, strategy);
    }

    @Override
    public String getNullableData(long timeout, String strategy) {
        if (ConfigHolderFactory.isInit(delagate.getAppName())) {
            return ConfigHolderFactory.getConfigDataHolder(delagate.getAppName()).getData(dataId);
        }

        return delagate.getNullableData(timeout, strategy);
    }

    @Override
    public void addListener(ConfigDataListener configDataListener, Executor executor) {
        delagate.addListener(configDataListener, executor);
    }

    @Override
    public void addListeners(List<ConfigDataListener> configDataListenerList, Executor executor) {
        delagate.addListeners(configDataListenerList, executor);

    }

    protected void doDestory() throws TddlException {
        delagate.destory();
    }
}