org.zodiac.loadbalancer.ribbon.predicate.MetadataServer Maven / Gradle / Ivy

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package org.zodiac.loadbalancer.ribbon.predicate;

import com.netflix.loadbalancer.Server;
import org.zodiac.commons.util.Colls;
import org.zodiac.sdk.toolkit.util.ReflectionUtil;
import org.zodiac.sdk.toolkit.util.collection.CollUtil;

import java.lang.reflect.Method;
import java.util.List;
import java.util.Map;

/**
 * 利用反射，让 server 直接支持 nacos、consul、Eureka。
 *
 */
public class MetadataServer {

    private final static Map, Method> METHOD_MAP = CollUtil.concurrentMap(1);
    private final static List> NO_METHOD_LIST = CollUtil.list();

    private final Server server;
    private final Method method;

    public MetadataServer(Server server) {
        this.server = server;
        this.method = findMetadataMethod(server.getClass());
    }

    private static Method findMetadataMethod(Class serverClass) {
        /*缓存中有方法。*/
        Method method = METHOD_MAP.get(serverClass);
        if (method != null) {
            return method;
        }
        /*没有方法。*/
        if (NO_METHOD_LIST.contains(serverClass)) {
            return null;
        }
        /*查找 getMetadata 方法。*/
        method = ReflectionUtil.findMethod(serverClass, "getMetadata");
        if (method == null) {
            NO_METHOD_LIST.add(serverClass);
        } else {
            METHOD_MAP.put(serverClass, method);
        }
        return method;
    }

    public boolean hasMetadata() {
        return method != null;
    }

    @SuppressWarnings("unchecked")
    public Map getMetadata() {
        return (Map)ReflectionUtil.invokeMethod(method, server);
    }

}