gu.simplemq.pool.BaseMQInstance Maven / Gradle / Ivy
package gu.simplemq.pool;
import java.lang.reflect.Constructor;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import com.google.common.base.Throwables;
import com.google.common.cache.CacheBuilder;
import com.google.common.cache.CacheLoader;
import com.google.common.cache.LoadingCache;
import gu.simplemq.exceptions.SmqRuntimeException;
/**
* 线程安全的消息组件实例管理类
* @author guyadong
*
* @param 消息组件组件类型
* @param 连接线程池类型
*/
public abstract class BaseMQInstance{
/** 保存每个 P对应的 R 实例 */
private final LoadingCache cache =
CacheBuilder.newBuilder()
.build(new CacheLoader(){
@Override
public R load(P key) throws Exception {
constructor.setAccessible(true);
return constructor.newInstance(key);
}});
/** R 的构造函数 */
private final Constructor constructor;
/**
* usage:new BaseMQInstance<Model,Pool>(){};
*/
@SuppressWarnings("unchecked")
protected BaseMQInstance() {
try {
Type superClass = getClass().getGenericSuperclass();
Class rClass = (Class) ((ParameterizedType) superClass).getActualTypeArguments()[0];
Class pClass = (Class
) ((ParameterizedType) superClass).getActualTypeArguments()[1];
constructor = rClass.getDeclaredConstructor(pClass);
} catch (Throwable e) {
throw new SmqRuntimeException(e);
}
}
protected void beforeDelete(R r){}
/** 删除{@link #instances}中所有实例,
* 如果实例实现了{@link AutoCloseable}接口则执行close方法 */
public synchronized void clearInstances(){
for(R r:cache.asMap().values()){
beforeDelete(r);
try {
if(r instanceof AutoCloseable){
((AutoCloseable)r).close();
}
} catch (Throwable e) {
Throwables.throwIfUnchecked(e);
throw new RuntimeException(e);
}
}
cache.asMap().clear();
}
/**
* 返回 {@link #instances}中 P 对应的R实例, 如果没有找到就创建一个新实例加入。
* @param pool
* @return R instance
*/
public R getInstance(P pool){
return cache.getUnchecked(pool);
}
}