29. 代码实例-设计模式-模板方法

（1）接口

public interface DataLock {

    /**
     * 从数据库中查询一定数量的OrderTask，并进行lock，lock到指定条数就返回,如果lock不到就返回空集合
     * @param modeSize 总模数
     * @param modeNo 当前锁定模数
     */
    public List<OrderTask> lockDatas(int modeSize, int modeNo);
    /**
     * 根据id锁定一条数据
     * @param id
     * @return true已锁定，false未锁定
     */
    public abstract boolean lockSingleData(long id);
    /**
     * 解锁指定数据
     */
    public int unLock(long id);

    /**
     * 解锁全部数据
     */
    public int unLockAll();

}

（2）模板类

public abstract class DataLockImpl implements DataLock {
    @Resource
    protected OrderTaskDao orderTaskDao;
    @Resource
    protected RouteUtil routeUtil;

    protected int maxLockSize;

    protected int getSize;

    @Override
    public List<OrderTask> lockDatas(int modeSize, int modeNo) {
        List<OrderTask> consumeInfoLocks = new ArrayList<OrderTask>();
        List<OrderTask> consumeInfos = getData();
        for (OrderTask consumeInfo : consumeInfos) {
            String pin = consumeInfo.getPin();
            if (StringUtils.isEmpty(pin)) {
                continue;
            }
            if (modeNo != routeUtil.getMode(pin, modeSize)) {
                continue;
            }
            if (lockSingleData(consumeInfo.getId())) {
                consumeInfoLocks.add(consumeInfo);
            }
            if (consumeInfoLocks.size() >= maxLockSize) {
                break;
            }
        }
        return consumeInfoLocks;
    }
    @Override
    public abstract boolean lockSingleData(long id);

    public abstract List<OrderTask> getData();

    public void setMaxLockSize(int maxLockSize) {
        this.maxLockSize = maxLockSize;
    }

    public void setGetSize(int getSize) {
        this.getSize = getSize;
    }

}

（3）具体类

@Service(value = "addConsumeLock")
public class AddConsumeLock extends DataLockImpl {

    @Override
    @Value("${addConsumeLock.getSize}")
    public void setGetSize(int getSize) {
        super.setGetSize(getSize);
    }

    @Override
    @Value("${addConsumeLock.maxLockSize}")
    public void setMaxLockSize(int maxLockSize) {
        super.setMaxLockSize(maxLockSize);
    }

    @Override
    public boolean lockSingleData(long id) {
        return orderTaskDao.updateStatus(id, OrderTask.SYN_LOCK, OrderTask.SYN_WAIT) == 1;
    }

    @Override
    public int unLock(long id) {
        return orderTaskDao.updateStatus(id, OrderTask.SYN_WAIT, OrderTask.SYN_LOCK);
    }

    @Override
    public List<OrderTask> getData() {
        List<OrderTask> orderTasks = orderTaskDao.findOrderTasksByConsumeStatus(OrderTask.SYN_WAIT, getSize, false);
        return orderTasks;
    }

    @Override
    public int unLockAll() {
        return orderTaskDao.updateStatus(OrderTask.SYN_WAIT, OrderTask.SYN_LOCK);
    }
}

package com.jd.consume.service.lock.impl;

import java.util.List;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Service;

import com.jd.consume.domain.OrderTask;

/**
 * 计算等级数据锁定
 * @author guanpanpan
 *
 */
@Service(value = "gradeLock")
public class GradeLock extends DataLockImpl {
    @Override
    @Value("${gradeLock.getSize}")
    public void setGetSize(int getSize) {
        super.setGetSize(getSize);
    }

    @Override
    @Value("${gradeLock.maxLockSize}")
    public void setMaxLockSize(int maxLockSize) {
        super.setMaxLockSize(maxLockSize);
    }

    @Override
    public boolean lockSingleData(long id) {
        return orderTaskDao.updateGradeStatus(id, OrderTask.LEV_LOCK, OrderTask.LEV_WAIT) == 1;
    }

    @Override
    public int unLock(long id) {
        return orderTaskDao.updateGradeStatus(id, OrderTask.LEV_WAIT, OrderTask.LEV_LOCK);
    }

    @Override
    public List<OrderTask> getData() {
        List<OrderTask> consumeInfos = orderTaskDao.findOrderTasksByLevStatus(OrderTask.LEV_WAIT, getSize, false);
        return consumeInfos;
    }
    @Override
    public int unLockAll() {
        return orderTaskDao.updateGradeStatus(OrderTask.LEV_WAIT, OrderTask.LEV_LOCK);
    }
}

注：本示例来源于consume-grade-sql