[GitHub] incubator-griffin pull request #444: Define griffin plain-vanilla hook.

[toyboxman <gi...@git.apache.org>]

Github user toyboxman commented on a diff in the pull request:

    https://github.com/apache/incubator-griffin/pull/444#discussion_r230045266
  
    --- Diff: service/src/main/java/org/apache/griffin/core/integration/GriffinEventListeners.java ---
    @@ -0,0 +1,61 @@
    +package org.apache.griffin.core.integration;
    +
    +import java.util.ArrayList;
    +import java.util.List;
    +import java.util.Scanner;
    +
    +import org.springframework.beans.factory.annotation.Value;
    +import org.springframework.boot.context.properties.ConfigurationProperties;
    +import org.springframework.context.annotation.Bean;
    +import org.springframework.context.annotation.Configuration;
    +import org.slf4j.Logger;
    +import org.slf4j.LoggerFactory;
    +import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
    +
    +@Configuration
    +@ConfigurationProperties(prefix = "internal.event")
    +public class GriffinEventListeners {
    +    private static final Logger LOGGER = LoggerFactory
    +        .getLogger(GriffinEventListeners.class);
    +    @Value("${internal.event.listeners}")
    +    private String listeners;
    +
    +    @Value("${internal.event.scheduler.thread.size}")
    +    private int threadPoolSize;
    +
    +    @Bean
    +    public ThreadPoolTaskExecutor getListenersScheduler() {
    +        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
    +        executor.setCorePoolSize(threadPoolSize);
    +        executor.setMaxPoolSize(threadPoolSize * 2);
    +        executor.setThreadNamePrefix("event_listener_task_scheduler");
    +        executor.initialize();
    +
    +        return executor;
    +    }
    +
    +    @Bean
    +    public List<GriffinHook> getListenersRegistered() {
    +        ArrayList<GriffinHook> hookList = new ArrayList<>();
    +        if (listeners == null || listeners.isEmpty()) {
    +            LOGGER.info("Disable griffin event listener for service.");
    +        } else {
    +            //split list of class name
    +            Scanner scanner = new Scanner(listeners).useDelimiter(";");
    +            while (scanner.hasNext()) {
    +                String hookName = scanner.next();
    +                try {
    +                    Class<GriffinHook> cl = (Class<GriffinHook>) Class.forName(hookName);
    +                    GriffinHook hook = cl.newInstance();
    --- End diff --
    
    I have no feasible/good idea to inject/load external listener now.
    
    so I used java reflection to new listener instance.
    
    let me think about spring inject functionality


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