Threadpool with pasistant worker instances
- by Matt Smokey-waters Holmes
So basically what im trying to do is queue up tasks in a thread pool to be executed as soon as a worker becomes free, i have found various examples of this but in all cases the examples have been setup to use a new Worker instance for each job, i want persistent workers.
Im trying to make a ftp backup tool, i have it working but because of the limitations of a single connection it is slow. What i ideally want to do is have a single connection for scanning directories and building up a file list then four workers to download said files.
Here is an example of my worker
/**
* FTP Worker
*/
public class Worker implements Runnable {
protected FTPClient _ftp;
// Connection details
protected String _host = "";
protected String _user = "";
protected String _pass = "";
// worker status
protected boolean _working = false;
public Worker(String host, String user, String pass) {
this._host = host;
this._user = user;
this._pass = pass;
}
// Check if the worker is in use
public boolean inUse() {
return this._working;
}
@Override
public void run() {
this._ftp = new FTPClient();
this._connect();
}
// Download a file from the ftp server
public boolean download(String base, String path, String file) {
this._working = true;
boolean outcome = true;
//create directory if not exists
File pathDir = new File(base + path);
if (!pathDir.exists()) {
pathDir.mkdirs();
}
//download file
try {
OutputStream output = new FileOutputStream(base + path + file);
this._ftp.retrieveFile(file, output);
output.close();
} catch (Exception e) {
outcome = false;
} finally {
this._working = false;
return outcome;
}
}
// Connect to the server
protected boolean _connect() {
try {
this._ftp.connect(this._host);
this._ftp.login(this._user, this._pass);
} catch (Exception e) {
return false;
}
return this._ftp.isConnected();
}
// Disconnect from the server
protected void _disconnect() {
try {
this._ftp.disconnect();
} catch (Exception e) { /* do nothing */ }
}
}
and basically i want to be able to call Worker.download(...) for each task in a queue whenever a worker becomes available without having to create a new connection to the ftp server for each download
Any help would be appreciated as iv'e never used threads before and I'm going round in circles at the moment
