Question

I’m running the java application using tomcat7.
I need to store the information per tomcat thread, so I can use the ThreadLocals approach.

In my server.xml the threadpool definition looks like the following:

 <Executor name="tomcatThreadPool" namePrefix="catalina-exec-" 
    maxThreads="10000" minSpareThreads="2000"/>

I have a class EnhanceThread

public class EnhanceThread extends Thread {
    ...
    @Override
    public void run() {
       SomeThreadLocals.set(data);
       super.run();
     }
}

How can I override the tomcat thread pool definition and make it use use my class?
Is there a better approach to threat this problem?

Answer 1

You don’t need to mess with Tomcat threads for that. Just use the following code:

public class JsonSerializerFactory {
    private static final ThreadLocal<JsonSerializer> JSON_SERIALIZER = 
        new ThreadLocal<JsonSerializer>() {
            @Override 
            protected JsonSerializer initialValue() {
                 return new JsonSerializer();
            }
        };

    public static JsonSerializer get() {
        return JSON_SERIALIZER;
    }
}

Each time you need a serializer, call JsonSerializerFactory.get(), and it will return the thread-local instance, and lazily create it if it doesn’t exist yet.