Closing Threads

[brinker]

Hi,

I have a pretty simple question. I have written a multithreaded program and it seem to work pretty well. However, when the threads are done their execution, the program does not seem to finish, but just hangs. I thought that when the threads finished their execution, the resources were simply absorbed back to the system.

If I use a System.exit(0) call after the thread.start() call, the program immediately terminates which is not what I want.

Does anyone have any tips on how to proceed.


thanks

 

[palbano]

If your using any subsystems like RMI JINI etc you can have thread created by those libraries that are waiting for a timeout before they will exit.

So if you are then let us know about that. If not then you have some sort of a logic problem, you can use logging to know exactly when each thread starts and exits.

-pete

 

[brinker]

Thanks Pete,

I tried using logging. In other words, I put simply output statements when the threads are about to exit. They seem to get to the point as wanted, but they do not die after that.

I am not using RMI or JINI. I thought that threads were supposed to die upon their completion. I have tried setting the threads to null internally after they finish from within the thread, but I am not totally sure how to go about it. The statement: this=null makes no sense.

thanks

 

[palbano]

>> I put simply output statements when the threads are
>> about to exit.

Post that code.

-pete

 

[brinker]

public class FThread extends Thread {
private File inputFile;
private DataInputStream input; //input file stream
private String infoString;
private StringBuffer outputString;
private String inputName;

public FThread(String Name, String FName) {
super(Name);
outputString=new StringBuffer(10); // hold the output info.
inputName=new String(FName);
}


public void run()
{
// now process the list of URLs by reading them, getting info, finding results, and printing results to a file
try {
loadInfo(inputName); //loading the list of URLs into a String.
}
catch (IOException e)
{
System.out.println(e.toString());
}
processList();
System.out.println("\nFinishing Up...."
finishup(); //finish up with the files and write output to a file.
}


private void processList()
{
// the processing of the list of URLs is done here.
String part;
int start=0;
int pos1=0, pos2=0, pos3=0;
long positionOut=1;
while (pos1!=-1)
{
pos1=infoString.indexOf(".com", start);
if (pos1!=-1)
{
part=infoString.substring(start,pos1+4);
// got it System.out.println("\n\n"+part+"\n"
process(part); // ie process the URL
start=pos1+5; //ie. eliminate the new line character
positionOut++;
}
if ((positionOut%10000)==0)
System.out.println("Thread "+getName()+ "done 10000 lines"
}

}

private void process(String urlName)
{
// get the information
URL currURL;
String resultS1,resultS2;
String result="";

try
{
//currURL=new URL("

http://www.narjit.com");

String temp="

http://inventory.overture.com/d/searchinventory/suggestion/?term="+urlName;

currURL=new URL(temp);

HttpURLConnection conn=(HttpURLConnection)currURL.openConnection();
conn.connect();
//get an input stream from the URL connection object
InputStreamReader isr=new InputStreamReader(conn.getInputStream());
BufferedReader in =new BufferedReader(isr);
String hold;
while ((hold=in.readLine())!=null)
{
result+=hold+"\n";
}
in.close();
//now try processing this garbage
int ind1=result.indexOf(&quot;<tr bgcolor=#333333>&quot;,0);
int ind2;
if (ind1!=-1)
{
ind2=result.indexOf(&quot;</td>&quot;,ind1+83);
resultS1=result.substring(ind1+83,ind2);
// also write the result to a string that will be piped at the end to an outputFile.
outputString.append(urlName+&quot; &quot;+resultS1+&quot;\n&quot;
in=null;
isr=null;
}

//String hold = currURL.getContent().toString();
//System.out.println(&quot;\ngot here&quot;
// System.out.println(urlName);
// no need to replace anything
//System.out.println(&quot;\ngot here&quot;
}

catch (ConnectException w)
{
System.out.println(&quot;Problem connecting with URL Info: &quot;+ urlName);
System.out.println(&quot;Retrying......&quot;
process(urlName); //internal call.
}
catch (BindException b)
{
//ie. too many processes running simultaneously.
System.out.println(&quot;Problem connecting with URL Info: &quot;+ urlName);
System.out.println(&quot;Retrying....&quot;
process(urlName); //internal call.
}
catch (Exception e)
{
System.out.println(&quot;Error. Retrying...&quot;
System.out.println(e.toString());
process(urlName); //internal call
}
currURL=null; // clear up the memory

}


private void loadInfo(String FName) throws IOException
{
inputFile=new File(FName);

StringBuffer infoList;
try {
input=new DataInputStream(new FileInputStream(inputFile));
}
catch (IOException e) {
System.out.println(&quot;Error Opening File&quot;
}

infoList=new StringBuffer(10);
char tmp;
try {
while(true) {
tmp=(char)input.readByte();
infoList.append(tmp);
}
}
catch (EOFException e) { }
System.out.println(&quot;Opened &quot;+FName);
//now set the text for the text area
infoString=new String(infoList.toString());
input.close();
}

public void finishup()
{
DataOutputStream output;
String fn=inputFile.getName();
int i = fn.indexOf(&quot;.txt&quot;
String nn=fn.substring(0,i);
String outputName=nn+&quot;O.txt&quot;;
File outFile =new File (outputName);
String outputN=new String(outputString.toString());
//output the string to a file
try {
output=new DataOutputStream(new FileOutputStream(outputName));

for (int j=0; j<outputN.length(); j++)
{
output.writeByte(outputN.charAt(j));
}
output.close();
}
catch (IOException e) {
System.out.println(&quot;Error Opening Save File&quot;
}
System.gc();
System.out.println(&quot;Thread &quot;+getName()+&quot; done...Exiting&quot;
}

}