The Silence of the Logs

Having noticed that an application server occasionally freezes, with dire consequences for the stability of the cluster, I set out to compute the longest pauses in the logs, using this indicator as a "freezing marker".
Here is the Java "script", it parses all logs in a directory, and for each log it prints the longest period without any activity in the log.
Enjoy.

package com.pierre.loggrepper;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStreamReader;
import java.text.DateFormat;
import java.text.SimpleDateFormat;



public class WebLogicLogGrepper {
	/** reads "Aug 28, 2011 8:02:45 PM" */

	DateFormat formatter = new SimpleDateFormat("MMM dd, yyyy h:mm:ss aaaa");
	String previousTimeString = null;
	long previousTime = 0;
	String topTimeString = "";
	long topDiff = 0;

	public static void main(String[] args) throws Exception {

		String DIR = "/home/oracle/Downloads/Temp-MSLogs/1/ms1logs/";
		File dir = new File(DIR);
		for (File file : dir.listFiles()) {
			if (file.getName().startsWith("eposprd_ManagedServer")) {
				WebLogicLogGrepper webLogicLogGrepper = new WebLogicLogGrepper();
				webLogicLogGrepper.run(file.getAbsolutePath());
			}
		}


	}

	public void run(String filename) throws Exception {
		FileInputStream fis = new FileInputStream(filename);
		BufferedReader br = new BufferedReader(new InputStreamReader(fis));

		String line = null; 

		while ((line = br.readLine()) != null ) {
			if (line.startsWith("####<")) {
				String currentTimeString = line.substring(5, 29);
				long currentTime = getTimeFromString(currentTimeString);
				if (previousTimeString == null) {
					previousTimeString = currentTimeString;
					previousTime = currentTime;
				}
				else {
					long timeDiff = currentTime - previousTime;
					if ( timeDiff > topDiff ) {
						topDiff = timeDiff;
						topTimeString = previousTimeString;
					}
					previousTime = currentTime;
					previousTimeString = currentTimeString;
				}

			}
		}
		System.out.println("topDiff=" + topDiff + " topTimeString=" + topTimeString);
	}

	/**
	 * Receives a "Aug 28, 2011 8:02:45 PM" and returns its Epoch
	 * @param timeAsString
	 * @return
	 * @throws Exception 
	 */
	public long getTimeFromString(String source) throws Exception {
		return formatter.parse(source).getTime();
	}



}