[Java]J2EE application performance optimization

http://www.javaworld.com/javaworld/jw-05-2004/jw-0517-optimization.html
http://www.javaworld.com/javaworld/jw-05-2004/jw-0517-optimization-p2.html
http://www.javaworld.com/javaworld/jw-05-2004/jw-0517-optimization-p3.html
読んだ読んだ。サーバのチューニングとかは大したことは書いてないけど、アプリケーションチューニングは、商用製品を使わないお手軽方法が書いてあった。

①以下のようなLogTimeStampクラスを作成する

import java.util.HashMap;

//Import org.apache.log4j.Logger;

public class LogTimeStamp {
    private static HashMap ht = new HashMap();

    // Preferably we should use log4j instead of System.out
//    private static Logger logger = Logger.getLogger("LogTimeStamp");

    private static class ThreadExecInfo {
        long timestamp;
        int stepno;
    }

    public static void LogMsg(String Msg) {
        LogMsg(Msg, false);
    }

    /*
     * Passing true in the second parameter of this function resets the counter for
     * the current thread. Otherwise it keeps track of the last invocation and prints
     * the current counter value and the time difference between the two invocations.
     */
    public static void LogMsg(String Msg, boolean flag) {
        LogTimeStamp.ThreadExecInfo thr;
        long timestamp = System.currentTimeMillis();

        synchronized (ht) {
            thr = (LogTimeStamp.ThreadExecInfo) ht.get(Thread.currentThread().getName());
            if (thr == null) {
                thr = new LogTimeStamp.ThreadExecInfo();
                ht.put(Thread.currentThread().getName(), thr);
            } 
        }

        if (flag == true) {
            thr.stepno = 0;
        }

        if (thr.stepno != 0) {
//            logger.debug(Thread.currentThread().getName() + ":" + thr.stepno + ":" +
//                    Msg + ":" + (timestamp - thr.timestamp));
            System.out.println(Thread.currentThread().getName() + ":" + thr.stepno + ":" +
                    Msg + ":" + (timestamp - thr.timestamp));
        }
        thr.stepno = thr.stepno + 1;
        thr.timestamp = timestamp;
    }

}

②以下のようにメソッドに埋め込む

public void startingMethod() {
        ...
        LogTimeStamp.LogMsg("This is a test message", true); //This is starting point
        ...
        LogTimeStamp.LogMsg("One more test message"); //This will become check point 1
        method1();
        ...
    }

③ログを取って、analyze.plでログを加工！！

おお。便利じゃ。