Netbeans for the Coffee Drinker

Using threading to do processing. Improving the User Experience.

Paul C — Thu, 05 Jan 2012 10:10:52 +0000

One great thing about Java is that it’s easy to create Threads. My UML diagrams are showing how I am now splitting processing away from the user interface.

Why make a user wait, when a background thread could be fired to do a calculation, produce a report and it’s not only users that can benefit from background processing. I have a comms routine which basically get’s a UDP message, puts it in a database and responds to the unit. Then, in the background, runs a thread that processes the data into the system.

To create a thread is very easy. You can either use an EJB timer function to start a threaded routine, or create a class that extends a Thread, and then use new Thread(new yourClass()).start();

Finding out where I am without an external API.

Paul C — Wed, 16 Nov 2011 13:00:35 +0000

My work is incredibly interesting. I do a LOT of mapping and location software, often it’s easy to plug in to something like Google Maps who provide their awesome API for programmers to hack. But sometimes this isn’t possible.

Of of my projects involves a world map with a plot of different devices locations. However in this case, as it was run in a back end query it would not be covered by any web api’s license. My own solution was needed. The first thing I did was to get some data, a cities table with 2.6 million entries is available free on the internet, and a countries table, I modified the cities table to include the country name.

Then I simply used a nested query on the cities table.

select * from cities where (lat>4.3142004 and lat<4.7142)
and (cities.long>-74.0833 and cities.long<-73.683304) limit 1

This effectively is a box surrounding the point I’m looking for. Note that if the box fails to find anything I can just increase the parameters and rerun the query.

You can see that the figures form a box around the point I’m looking for, in this case I did not need the address, just what country it was in. (returned the whole record for testing).

Incidentally the cities table is pretty interesting, you wouldn’t believe how many London’s there are!

The cities file can be downloaded here

Primefaces Tree in a layout or panel doesn’t work

Paul C — Thu, 20 Oct 2011 07:31:07 +0000

I must be losing more hair than anything. The tree function in a layout doesn’t work, although the backing bean is called the selectedItems array passed to it is empty. So here’s the fix.

Your code now looks like this probably (or something like it).

So simply create another xhtml file and put the tree in it on it’s own. In this case I called it treeTest.xhtml





Tracking

Now in your original file replace your tree code with an iframe! Tada, it all works! (note it should have < at the start and > at the end but wordpress goes a bit mad if I do that.

iframe src="treeTest.xhtml" style="height:80%;border-style:none;border-width:1px;" >
By the way this is fixed in the latest V3.0M

Now that’s clever.

Paul C — Thu, 13 Oct 2011 09:26:48 +0000

OK,

So to upgrade my iPhone to IOS 5 I decided to go to the pub, have a nice meal and a pint of cider. Great idea you say. But, due to the cider I unplugged my iPhone before it had finished syncing the apps. No problem, I thought I’ll just sync it in the morning. Some of the apps were missing some would not work when I touched them.

Morning comes, upgrade iPad…and guess what… all my apps are working, seems little iPhone synced itself with the cloud and fixed itself…scary wonderful technology.

Well done Apple. Steve would be proud because I know I am.

IOS 5 out NOW but…

Paul C — Wed, 12 Oct 2011 17:18:36 +0000

I think their servers are suffering, 16 hours on a broad band line for the iPhone version 53 minutes though for the iPad version ….

Apple, you should have started the update WHILE THE USA WAS ASLEEP! silly.

Ok some of us have been sitting in iTunes and hitting Check for Update all day…

RIP Steve Jobs

Paul C — Thu, 06 Oct 2011 14:32:29 +0000

I just wanted to pay tribute to Steve Jobs for his incredible contribution to IT on this Blog. I look forward to the future but Steve will be a sad loss to all of us who use Apple stuff and a few who don’t.

com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: No operations allowed after connection closed.

Paul C — Tue, 27 Sep 2011 09:11:00 +0000

Before you do any of the following make sure you are using the very latest MYSQL driver.

I have been hunting through the internet to find a solution to this one, after about 24 hours it seemed that the Glassfish 3 server could no longer find connections. The solution was actually in the error message (but you know how you never read ALL the way through a java error message).

The last packet successfully received from the server was 48,673,937 milliseconds ago. The last packet sent successfully
to the server was 48,673,937 milliseconds ago. is longer than the server configured value of 'wait_timeout'. You should
consider either expiring and/or testing connection validity before use in your application, increasing the server
configured values for client timeouts, or using the Connector/J connection property 'autoReconnect=true' to avoid this problem. at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57) at

Actually this is middy deceptive, because you need to set more than that.

I set in my sun-resources.xml file…

And in fact any where else you make a connection. Ensure that the auto reconnect is set to true. You could also set the number of retries in the reconnections to a higher property (default is 3).

Full details of these properties are usefully available here

Oh and a gotcha, don’t forget that if you have an app/jdbc resource on the server you need to add the properties to it in the jDBC connection pool and restart the server otherwise it won’t get there!

If none of that works, try making sure that the glass fish server only keeps the connections open for a shorter time than the mysql server.

In your connection pools…

Pool Settings

Initial and Minimum Pool Size:	Connections Minimum and initial number of connections maintained in the pool
Maximum Pool Size:	Connections Maximum number of connections that can be created to satisfy client requests
Pool Resize Quantity:	Connections Number of connections to be removed when pool idle timeout expires
Idle Timeout:	Seconds Maximum time that connection can remain idle in the pool
Max Wait Time:	Milliseconds Amount of time caller waits before connection timeout is sent

If none of this works and you still have the problem (which is odd on one glass fish server this fixed it) then change the datasource from a connection pool driver to an XA datasource driver.

Pool Name:	my connectionpoolname
Resource Type:	javax.sql.DataSource javax.sql.XADataSource javax.sql.ConnectionPoolDataSource java.sql.Driver Must be specified if the datasource class implements more than 1 of the interface.
Datasource Classname:

Sending a text through txtlocal.com (or how to do a post to a page)

Paul C — Fri, 09 Sep 2011 07:56:59 +0000

The java examples they provide require the use of an apache library that has superseded. So I wrote my own using simple java libraries. No extras needed.

Obviously you’ll have to get yourself a txt local free text account before you go ahead….

http://www.txtlocal.co.uk/?tlrx=89707

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

package phj;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.URL;
import java.net.URLConnection;
import java.net.URLEncoder;

/**
 *
 * @author paulc
 */
public class SMSSender {

    public String sendSms(String sToPhoneNo,String sMessage) {

    try {
    // Construct data
    String data = URLEncoder.encode("uname", "UTF-8") + "=" + URLEncoder.encode("txtlocalusername****", "UTF-8");
    data += "&" + URLEncoder.encode("pword", "UTF-8") + "=" + URLEncoder.encode("txtlocalpassword****", "UTF-8");
    data += "&" + URLEncoder.encode("message", "UTF-8") + "=" + URLEncoder.encode(sMessage, "UTF-8");
    data += "&" + URLEncoder.encode("from", "UTF-8") + "=" + URLEncoder.encode("from email address", "UTF-8");
    data += "&" + URLEncoder.encode("selectednums", "UTF-8") + "=" + URLEncoder.encode(sToPhoneNo, "UTF-8");
    data += "&" + URLEncoder.encode("info", "UTF-8") + "=" + URLEncoder.encode("1", "UTF-8");
    // Send data
    URL url = new URL("https://www.txtlocal.com/sendsmspost.php");
    URLConnection conn = url.openConnection();
    conn.setDoOutput(true);
    OutputStreamWriter wr = new OutputStreamWriter(conn.getOutputStream());
    wr.write(data);
    wr.flush();

    // Get the response
    BufferedReader rd = new BufferedReader(new InputStreamReader(conn.getInputStream()));
    String line;
    String sResult="";
    while ((line = rd.readLine()) != null) {
        // Process line...
        sResult=sResult+line+" ";
    }
    wr.close();
    rd.close();
    return sResult;
} catch (Exception e) {
    System.out.println("Error SMS "+e);
    return "Error "+e;
}

    }
}

Obviously mine is more complex now (hence not final/static), just replace username, password and from email.

Javascript isDate function for UK

Paul C — Fri, 02 Sep 2011 09:17:42 +0000

Us splendid chaps in the UK have our date formatted dd-mm-yyyy, whilst this is obviously the correct way one should speak, it means that most is date functions for javascript don’t work for us.

Here’s one I found someone else modified for the UK. Splendid!

function isDate(dateStr) {

var datePat = /^(\d{1,2})(\/|-)(\d{1,2})(\/|-)(\d{4})$/;
var matchArray = dateStr.match(datePat); // is the format ok?

if (matchArray == null) {
alert("Please enter date as either dd/mm/yyyy or dd-mm-yyyy.");
return false;
}

month = matchArray[3]; // p@rse date into variables
day = matchArray[1];
year = matchArray[5];

if (month < 1 || month > 12) { // check month range
alert("Month must be between 1 and 12.");
return false;
}

if (day < 1 || day > 31) {
alert("Day must be between 1 and 31.");
return false;
}

if ((month==4 || month==6 || month==9 || month==11) && day==31) {
alert("Month "+month+" doesn`t have 31 days!")
return false;
}

if (month == 2) { // check for february 29th
var isleap = (year % 4 == 0 && (year % 100 != 0 || year % 400 == 0));
if (day > 29 || (day==29 && !isleap)) {
alert("February " + year + " doesn`t have " + day + " days!");
return false;
}
}
return true; // date is valid
}

My Macbook Pro broke :-( (well I installed something I shouldn’t have)

Paul C — Tue, 30 Aug 2011 16:47:25 +0000

TRAGEDY! (well actually it wasn’t)

My Macbook Pro took a dislike to an app I installed (geektools!) and went into a slow down mode I’ve never known, to the point the only option was to restore my Time Machine backup.

I keep a 200gb drive plugged in via USB as Time Machine allows me to restore individual files. But doing a whole restore was a completely different thing.

Here’s how.

a. Boot Computer and Hold Down CONTROL
b. Choose Recovery (you’ll see your normal drive and the recovery option)
c. Choose Recover from Time Machine….

Drink tea and wait 2 hours.

After then, rebooted and everything was restored.