com.kould.core.impl.BaseCacheHandler Maven / Gradle / Ivy
package com.kould.core.impl;
import com.kould.api.Kache;
import com.kould.entity.Status;
import com.kould.core.CacheHandler;
import com.kould.entity.NullValue;
import com.kould.exception.KacheAsyncWriteException;
import com.kould.function.KeyFunction;
import com.kould.function.ReadFunction;
import com.kould.function.WriteFunction;
import com.kould.listener.ListenerHandler;
import com.kould.entity.MethodPoint;
import java.lang.reflect.Method;
import java.util.Arrays;
import java.util.Map;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ConcurrentHashMap;
public class BaseCacheHandler extends CacheHandler {
private static final Map> FUTURE_INDEX = new ConcurrentHashMap<>();
@Override
public Object load(MethodPoint point, boolean listenerEnable, ReadFunction readFunction
, WriteFunction writeFunction, KeyFunction keyFunction , String types, Status methodStatus) throws Exception {
Method daoMethod = point.getMethod();
String methodName = daoMethod.getName() ;
//该PO领域的初始化
//需要使用types表示其所涉及的缓存Bean的Class
String key = keyFunction.encode(point, methodName, types, methodStatus);
//对types进行处理,获取其主缓存Bean的Class名传入
String mainType = types.split(Kache.SPLIT_TAG, 2)[0];
//key拼接命名空间前缀
Object[] daoArgs = point.getArgs();
//以PO类型进行不同持久类领域的划分并拼接参数与方法作为幂等凭据
String lockKey = (mainType + methodName + Arrays.hashCode(daoArgs));
//获取缓存
Object result = readFunction.read(key , mainType);
if (result == null) {
// 通过新建Future进行异步写入,FUTURE_INDEX保证线程安全避免重复写入
// 避免纵向（单一节点）击穿,而允许横向（分布式）击穿
CompletableFuture completableFuture = FUTURE_INDEX.computeIfAbsent(lockKey, k -> CompletableFuture.supplyAsync(() -> {
try {
ListenerHandler.notHit(key, methodName, daoArgs, mainType, listenerEnable);
return writeFunction.write(key , point, mainType);
} catch (Exception e) {
throw new KacheAsyncWriteException(e.getMessage(),e);
}
}));
// 堵塞读取,聚集该击穿至写入时间内的线程统一获取数据并解除堵塞
result = completableFuture.get();
// 该次击穿结束，移除该Future帧避免下次击穿获取脏值
FUTURE_INDEX.remove(lockKey);
} else {
ListenerHandler.hit(key, methodName, daoArgs, mainType, listenerEnable);
}
//空值替换
if (result instanceof NullValue) {
result = null ;
}
return result;
}
}