How can I adapt my java program to continually run and execute periodically?

Question

I wrote the following section of java which picks up a plaintext file, converts it into an HTML file, and then FTPs the file to a web server. As the plaintext source file is constantly being updated, I would like this to continually run on a semi-regular basis. I looked into using the Task Scheduler in Windows XP (yes, I am on a dinosaur machine), but the most frequent option was once a day. Is there an efficient/somewhat simple way to use a sleep command and only execute every 15 minutes/hour?

I am including my code for context:

import java.io.*;
import java.util.*;
import org.apache.commons.net.ftp.FTP;
import org.apache.commons.net.ftp.FTPClient;
import java.sql.Timestamp;

public class PrintOutConvosFtp2
{
public static void main(String[] args) throws IOException
    {

    //Read in the conversation log
BufferedReader reader = new BufferedReader(new FileReader("C:/Documents and Settings/Cuckoo/Desktop/Syss-convos.LOG"));
FileWriter output = new FileWriter("C:/Documents and Settings/Cuckoo/Desktop/Conversations.html");
List<String> lines = new ArrayList<String>();
String line = null;
while ((line = reader.readLine()) != null)
    //remove some unnecessary clutter from the log
 {
 if (!(line.contains("just hung up!!!") || line.contains("just left the Realm.")
        || line.contains("Hurry, I've many esoteric secrets to divulge, and welcome to BaDbOy's realm.")
        || line.contains("For custom MegaMud paths and additional information, check out the website:")
        || line.contains("Syss gossips: Discuss new ideas/issues & see the most up to date information on Facebook!")
        || line.contains("Syss gossips: http://www.facebook.com/groups/EsotericEdits/")
        || line.contains("Syss gossips: MME Dats, Megamud path files and quest walkthroughs are available at my site")
        || line.contains("Syss gossips: www.esoteric-edits.fhero.net")
        || line.contains("telepaths: @")
        || line.contains("I'm a bot.  Try telepathing me with @commands.")
        || line.contains("Syss gossips: Remember, you can telepath me @commands for useful things like adding lives.")
        || line.contains("Syss gossips: Bring a friend, help keep mud alive!")
        || line.contains("You say \"http://esoteric-edits.fhero.net/\"")
        || line.contains("For a list of available commands, you can telepath me with @commands.")))
 {
 //make the dates american style
     String day = line.substring(0,2);
     String month = line.substring(3,5);
lines.add(month + "/" + day + line.substring(5));
}


 }
//initialize the output file with HTML header
output.write("<html>");
output.write(System.getProperty("line.separator") + "\t<head>");
output.write(System.getProperty("line.separator") + "\t\t<link type=\"text/css\" rel=\"stylesheet\" href=\"stylesheet.css\"/>");
output.write(System.getProperty("line.separator") + "\t\t<title>Esoteric Edits BBS - Conversation Log</title>");
output.write(System.getProperty("line.separator") + "\t</head>");
output.write(System.getProperty("line.separator") + "\t<body>"+ System.getProperty("line.separator") + System.getProperty("line.separator"));
output.write(System.getProperty("line.separator") + "<div id='cssmenu'>");
output.write(System.getProperty("line.separator") + "\t\t<center><img src=\"logo_10_2.png\">");
output.write(System.getProperty("line.separator") + "<ul>");
output.write(System.getProperty("line.separator") + "\t<li> <a href='index.html'><span>Home</span></a></li>");
output.write(System.getProperty("line.separator") + "\t<li> <a href='downloads.html'><span>Downloads</span></a></li>");
output.write(System.getProperty("line.separator") + "\t<li> <a href='Quests.html'><span>Quest Walkthroughs</span></a></li>");
output.write(System.getProperty("line.separator") + "\t<li> <a href='https://www.facebook.com/groups/EsotericEdits/'><span>Facebook</span></a></li>");
output.write(System.getProperty("line.separator") + "\t<li> <a href='captures.html'><span>Captures</span></a></li>");
output.write(System.getProperty("line.separator") + "\t<li class='last'> <a href='FAQs.html'><span>FAQs</span></a></li>");
output.write(System.getProperty("line.separator") + "</ul></center>");
output.write(System.getProperty("line.separator") + "</div><div id='mainpage'>");
output.write(System.getProperty("line.separator") + "<center><img src=\"divider.png\"></center>");

//write out a new file with HTML coloration
for (ListIterator<String> iter = lines.listIterator(); iter.hasNext(); ) 
{
    String currentline = iter.next();
    output.write("<b>"); //make everything bold
    if (currentline.contains("gangpaths: "))
{
output.write(System.getProperty("line.separator") + "<font color=\"#808000\">" + currentline + "<br></font>");
}
    else if (currentline.contains("gossips: ") || currentline.contains("auctions: "))
{
output.write(System.getProperty("line.separator") + "<font color=\"#FF00FF\">" + currentline + "<br></font>");
}
else if (currentline.contains("Broadcast from "))
{
output.write(System.getProperty("line.separator") + "<font color=\"yellow\">" + currentline + "<br></font>");
}
else if (currentline.contains("says \"") || currentline.contains("greets you.") || currentline.contains("bows deeply.")
             || currentline.contains("breaks into a wide grin.") || currentline.contains("You say \"") 
             || currentline.contains("nods affirmatively.") || currentline.contains("grin slyly"))
{
output.write(System.getProperty("line.separator") + "<font color=\"green\">" + currentline + "<br></font>");
}
else
{
output.write(System.getProperty("line.separator") + currentline + "<br>");
}
}
//finalize the HTML footer
output.write(System.getProperty("line.separator") + "</b>");
output.write(System.getProperty("line.separator") + "</div>");
output.write(System.getProperty("line.separator") + "</body>");
output.write(System.getProperty("line.separator") + "\t</html>");
output.close(); //file is finalized locally

//Log file location for FTPs
Writer writer = new BufferedWriter(new FileWriter("C:/Documents and Settings/Cuckoo/Desktop/Convo-Upload.log", true));

//define variables for FTP process
String server = "servername";
int port = 21;
String user = "fake";
String pass = "password";

//begin FTP process to web server
FTPClient ftpClient = new FTPClient();
FileInputStream fis = null;
try {

    File localFile = new File("C:/Documents and Settings/Cuckoo/Desktop/Conversations.html");
    ftpClient.connect(server, port);
    ftpClient.login(user, pass);
    ftpClient.setFileType(FTP.BINARY_FILE_TYPE);
    fis = new FileInputStream(localFile);
    String remoteFile = "/public_html/Conversations.html";
    ftpClient.storeFile(remoteFile, fis);
    java.util.Date currentDate = new java.util.Date();
    Timestamp currentTimestamp = new Timestamp(currentDate.getTime());
    writer.append("Successfully uploaded file as of " + currentTimestamp.toString() + System.getProperty("line.separator"));
    ftpClient.logout();
} catch (IOException e) {
    e.printStackTrace();
} finally {
    try {
        if (fis != null) {
            fis.close();
        }
        ftpClient.disconnect();
    } catch (IOException e) {
        e.printStackTrace();
        }
    }

writer.close(); //close the FTP logger
}
}

possible duplicate of [How do I schedule a task to run at periodic intervals?](http://stackoverflow.com/questions/4544197/how-do-i-schedule-a-task-to-run-at-periodic-intervals) — Raedwald, Jul 19 '14 at 09:35

score 2 · Accepted Answer · answered Jul 19 '14 at 09:17

You can make the program sleep for 15 minutes between executing its logic. That way the program is constantly running (no need for a scheduler to restart it), but it'll sleep while it's not doing its thing. Of course if the program exits/crashes, you'll need to somehow notice and restart it.

Basically wrap it all in a while loop and add a Thread.sleep(...); at the end of the loop.

score 1 · Answer 2 · edited Apr 13 '17 at 12:13

The Windows XP task scheduler can be set to run more often. You need to go to the Advanced tab. See this answer How to schedule task to run every 10 minutes, from 8:00 to 15:00 on multiple days of week (with schtask.exe)?

Alternatively, you could use the Watch Service API. See http://docs.oracle.com/javase/tutorial/essential/io/notification.html for more information. Note that this requires Java 1.7 or later.

"The java.nio.file package provides a file change notification API, called the Watch Service API. This API enables you to register a directory (or directories) with the watch service. When registering, you tell the service which types of events you are interested in: file creation, file deletion, or file modification. When the service detects an event of interest, it is forwarded to the registered process. The registered process has a thread (or a pool of threads) dedicated to watching for any events it has registered for. When an event comes in, it is handled as needed."

How can I adapt my java program to continually run and execute periodically?

2 Answers2