Grab the software you need.

Here's a short list of some of the things that you will need to have to follow along with me.

An actual JDK:

Okay in order to develop with Java you need a Java Development Kit.

I usually run with OpenJDK but you can always choose the Sun JDK. If you go with OpenJDK get version 6. Simply because that's all I'm going to cover for now. At some time in the near future ditch 6 for 7 but for now stick with 6, it is more tested and has fewer bugs in the JVM.

A Java EE server:

You'll need one of these in order to run your crap, er, programs. I like JBoss and I usually prefer it for EE 5 development (RedHat just released a EE 6 server but I haven't had time to test drive it). However, here I'm going to be using Glassfish v 3.0.1. It is a EE 6 server, and version 2.1.1 is a very good EE 5 server, it's what we used at work for some time. I'm going to be using the Web Profile version as opposed to the full version. You can grab that if you want but very rarely do I venture into a need for RMI-IIOP (using the server to distribute logic to clients). Later down the road I may cover RMI but for now I'm just going to cover WebEE.

A database!!:

I like MySQL. PostgreSQL is nice too. I won't get into too many details, in my clique there are some very sided opinions about which is better than the other. Do not forget to pick up the JDBC driver from whoever you choose.

A JPA library:

Glassfish comes with EclipseLink which is an awesome JPA provider. It's also the one that I will be using here. Other than it is provided with Glassfish, I know a good deal of the JPA hints for this stack, so I'm really in my zone with this. If you went out and got JBoss, you'll need to go grab EclipseLink here.

An IDE:

Okay notepad is great and all but at some point you're going to need to ditch it because it sucks as a development tool. Basically at some point everything just blends together and you spend more time trying to parse your source code with your eyes or you spend more and more time with comments to keep everything in some sort of order.

At a bare minimum you need an editor that can do syntax highlighting, this prevents all that black and white running together. One that can do auto-indentation (saves you at least five or ten minutes every day per project), auto-brackets (saves at least two or three minutes per day), and has the terminal very close by is even better (like Kate or gedit.) A full blown-out IDE like Eclipse or NetBeans can shave off thirty minutes to an hour per day per project if you get down in there and learn to really use it.

I'm going to be using NetBeans here for most of the examples. One, because it was one of the first Java IDEs I ever used and two, it was the one my college professor told us to use. See this is why Microsoft is making a killing in our college's in the Untied States, most...(never mind getting off topic).

Go get Netbeans here.

---

That looks like a lot to go get. Just remember that you are setting up for whatever may come your way. Aside from having some sort of code repo software (like git or so) you're basically using the same tools that a professional would be using for this task.

Well I better get myself off to bed. Cheers!

POJO extends vs implements

In Java we have two way that we implement inheritance either one extends a super class or implements an interface.

In JavaEE frameworks you will see a lot of this and understanding the difference between the two is pretty important.

Interfaces in Java have no actual code to back up the Interface. In other words implementing an interface requires you to add in all the code for the specified members in the interface. So what's the big deal then with interfaces?! They don't save you time do they? Usually an interface provides a hook into a library or a function of the EE server, so usually an interface will hook one object into another or the server proper.

Extending an object, however, provides the base class' implementation if you're feeling a bit lazy. Usually you will extend base classes to make something more specific to your use case. Going from something like a data table to an Employee data table. In Java you only get to extend one super class, as opposed to interfaces (which you can implement as many as those you want). I remember coming from all my C++ to Java and being frustrated at this.

---

It is also important to know about generics, generics allow your class to apply to more than one data type. For example instead of extending data table into employee data table, one could make data table generic data table<?>. Then you could say data table<Employee> or data table<Student>. Generics are extremely helpful for making common web concepts, like pagination, thumb viewers, and so on. The reason being is that the functionality doesn't change based on data type (A picture swoosher does the same thing to PNG as it would to JPG).

Finally annotations play a huge role in EE development in Java. Annotations allow a developer to add meta-data to their objects. A server can then read in this meta-data and change how it will behave with the object. Annotations only change the user's behavior not the objects. Remember that!

---

So why the lesson in general Object Oriented Programming? I think some people loose sight of the basics of computer science and that usually tends to lead to bad implementations of concepts.

I remember one time a person creating an interface with the action method to create a step-by-step process. I went back an implemented as a linked list style reader. People could use annotations to guide the reader like @PreCondition, @CleanUp,and of course @Action.

Of course no one is perfect, so I wouldn't say that anything on this blog is the end all, be all for implementations.

New Year, New Look, New Goal!

So it's a new year and I've changed the look of my Blogger account!

---

So I've also decided to realign my goal for info on this blog. The old stuff

will stay but I'm going to be better as keeping to one clear point, following it

through and not get side track too much.

I think it will be better overall this way.

SO! With that let's begin with the first topic.

JavaEE a broad view of what it is...

JavaEE is a collection of many different Java components to create a platform for server programming using Java (VM not language).

Basically it allows you to write software that will run and/or be distributed by servers running a JVM with the needed libraries. It is these libraries that separate JavaSE and JavaEE.

The platform is currently at version six but remember that the EE platform is a collection of components, each with their own version number.

Here is a quick table of some of the components in JavaEE 6. Now this is not a complete list, but this will cover the basics.

Component	Version	Summary
Servlet	3.0	Provides a means for a Java Object to provide a web page
Java Server Pages (JSP)	2.2	Allows the creation of Servlets using HTML files and java code embedded in the HTML code (very much like PHP)
Java Server Faces (JSF)	2.0	Provides a standard MVC library to HTML pages
Enterprise JavaBeans (EJB)	3.1	Provides a means to encapsulate business logic and deploy that logic to clients
Java Persistence API (JPA)	2.0	Provides a standard persistence layer to databases and Object Relationship Mapping (ORM).

Again this is just a brief overview of all that is in JavaEE 6.

Next post will cover POJOs and Interfaces.

Cheers!

Screen Scraping and scripting AS400 with Java!!

If you are like me you've been pulling your hair out trying to mess with the TN5250 stream so that you can automate things from you Java applications.

Well stop messing with the protocol itself and let TN5250j do that for you.

Here's how to do it with Netbeans 6.9:

First get TN5250j from here.

Next you will need Netbeans, duh. Netbeans!

Now start a new Java application. On the next screen name the program TestApp.

Now make Main.java say the following:

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

package testapp;

import java.net.UnknownHostException;
import org.tn5250j.Session5250;
import org.tn5250j.beans.ProtocolBean;
import org.tn5250j.framework.tn5250.Screen5250;
import org.tn5250j.framework.tn5250.ScreenPlanes;

public class Main {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) throws UnknownHostException, InterruptedException {
        ProtocolBean pb = new ProtocolBean("test", "123");
        pb.setHostName("192.168.1.2");
        Session5250 session = pb.getSession();
        pb.connect();
        Screen5250 screen = session.getScreen();
        char [] buffer = new char[1920];
        StringBuilder sb = new StringBuilder();
        Thread.sleep(3000L);
        screen.GetScreen(buffer, 1920, ScreenPlanes.PLANE_TEXT);
        String showme = new String(buffer);
        for(int i=0;i<showme.length();i+=80) {
            sb.append(showme.substring(i, i+80));
            sb.append("\n");
        }
        System.out.println(sb.toString());
        session.disconnect();
    }

}

Run your program and you should see the results in your output window.

Let me run through these lines. I'll have to break up a detail description of each line over the next few post.

ProtocolBean is a bean that the TN5250j exposes that allows programmers to use the bulk of TN5250j's api to control the TN5250 data stream. It wraps all the nasty stuff into one nice little bean. There is one catch to this. You cannot use the ProtocolBean inside of the AWT-Event Loop. So if you are doing a GUI then you'll need to start the session outside of the AWT-Event Loop.

The ProtocolBean has two constructors. I'm using the more basic one here. Using the basic ctor means that you have to call a couple of methods from ProtocolBean before starting up. I'll cover the other ctor later. Here we call the setHostName method which should not surprise you that it sets the IP address of the host.

Oh and by-the-by if you are wondering what the ctor for the protocol bean is doing... The first argument creates a config file that TN5250j will use and the second names the session. So if you've ever used the PCOMM ECL then you know all about this, if not, Sessions have two names an ID and a name. The ID runs from 1 to 65536 or so, in the order that you start them. The name is whatever you like to call stuff. Libraries, can access a client by either the ID... Look I'm getting off topic, we'll save all that for another day.

Okay next thing is the Session5250. We grab the session first and then connect. Long story short, you should always grab the session first and then call the connect method from the protocol bean.

Next is to grab the screen. Now I'm on a really slow connection so I added a Thread.sleep() to slow things down. I'll cover later how you can actually check if the connection is ready to be used.

First grab the screen into a Screnn5250 object.
Next we need to make a char[] it will act as a buffer for all the data that we will get form the TN5250 stream. Yes, this is how you must do it. No, there is no way around it. I've checked the source code for TN5250j.

Next I'm just going to print to stdout the actual screen. My screen defaults to 24x80. Most of the time this is what the stream will always be. However, at my company we have a system that does 27x132. You need to check to make sure that the system isn't requesting 27x132 because most of the time this will make the session end abnormally if you don't report that you can handle 27x132.

As you can see I use a for loop to add a new line at every 80 chars. This makes it look exactly like the terminal.

Oh yeah if you are wondering about that GetScreen method. The parameters are char[] that will act as the buffer. How large is the buffer? And from which plane should I get data from? I'll explain ScreenPlanes.PLANE_TEXT later. For now that's the one that you want.

Anyway...

So then I System.out.println() my StringBuilder.

Then I call the disconnect method from the session object.

You can download the source code for TN5250j and read all about the Session5250 and Screen5250 classes.

I've got to go for now!

Oh and...

Just wanted to let you all know that the company Glassfish server was moved to version 3.0.1. We had no problems with 2.1 per se. We moved to 3.0.1 because we got clustering working, JNLP working, and we really needed some of the features of 3.0.1. Don't know which ones but the 3.0.1 was the one that we all finally settled on.

I was pushing JBoss but they would like to see 6.0 out of RC before going down that road.

Been gone for a while.

Well it's sad but I've been a way for a bit, at least blogging.

As you may know, Oracle bought out Sun and pretty much every Java community that was started by Sun and was still under Sun's wings during the last days have all abandoned Oracle. I don't blame them.

So I heard from friends, "So are you going to continue to develop using Java?"

The answer is of course. The JVM and the Java platform is not entirely Oracle's, they do have leadership over the core but the community of Java projects still exist, just no longer listening to Oracle. Oracle is slowly loosing the Java community and with it the fresh ideas that the community has produced, such as JSF 2.0 and EJB 3!

In the end Oracle will be playing catch up and Java's core will suffer but the community which has driven Java development for the last ten years will still stay strong. It's a shame because ideas from the community were actually being placed into the core Java spec towards the end of Sun's days.

Java as a platform isn't dead, the Java community isn't dead, just our relationship with Oracle. It's a shame that the bottom dollar is the only thing that they seem to think about but it's their bloody company and they can run how they please.

So what about Oracle's contributions to the open source world?

If you head over to Oracle's website you'll see the contributions that Oracle has made to the OSS community...

If you review all of their contributions you will see that they all lead back to Oracle products. I see their contributions on the same level as the Visual Studio Express versions that Microsoft offers. The independents will all die a slow death, which is sad because bringing them back via an OSS fork is always a slow to start process. Just look at OpenOffice.org and now Libre Office.

This shouldn't come as a surprise to anyone. But I think that this will make the Java community tighter and closer knit. Yes it does toss Java back about five to seven years, community / corporate wise, but I think the OpenOffice people are showing us all what the Netbeans, MySQL, Glassfish people will all eventually come to do, break ties with a company that refuses to work with the community and instead does the equal of food dumping into the open source community.

I will start posting more, I swear this time! We'll start slow, maybe twice a week?

Throbber for Java

Have you ever wanted to do a please wait for a Java application?  Did you want a little spinny logo to animate while they waited?

As Professor Fransworth would say, "Good news everybody!"

Let's start out with a preview of the graphic that I'll be using.


Now this is actually nine different images, I've just haphazardly put them into one image here so you can see what I'm doing. I made these images in about five minutes using Inkscape but you can use whatever. You do need to export the images into a format that Java understands, I usually default to png.

I've named the rotor images rotor1.png through rotor8.png and the final image (the check mark) as rotord.png. The check mark is optional and the code below is clear cut enough to be able to remove the check mark. At any rate I'm placing the images into a package called sample.img

Now here's what we need to do. We need to create a custom JFrame (of Swing fame) that will be our spinning logo. IF you are using Netbeans, DO NOT USE NEW JFrame CLASS. If you are using Netbeans select Create New Java class. This gives you a no frills attached blank document with a shell of a Java class to begin with. If you do use the JFrame class in Netbeans it adds an XML document behind the scenes that allows you to use the GUI-fied editor, which will only serve to get in your way, in this case at least.

So let's build our customer JFrame.

package sample.ui;

import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.Toolkit;
import javax.swing.JPanel;

/**
 *
 * @author John Doe
 */
public class RotorPanel extends JPanel {

    private Image[] rotorImg;
    private Image rotorComplete;
    private boolean done;
    private int current = 0;
    private final int max_image = 7;

    public RotorPanel() {
        this.rotorImg = new Image[max_image+1];
        for(int i=0; i<max_image+1; i++)
            this.rotorImg[i] = Toolkit.getDefaultToolkit().createImage(getClass().getResource("/sample/img/rotor" + (i+1) + ".png"));
        this.rotorComplete = Toolkit.getDefaultToolkit().createImage(getClass().getResource("/sample/img/rotord.png"));
        this.done = false;
    }

    @Override
    public void paint(Graphics g) {
        super.paint(g);
        Graphics2D g2 = (Graphics2D) g;
        if(!done)
            g2.drawImage(this.rotorImg[this.current], 0, 0, this);
        else
            g2.drawImage(this.rotorComplete, 0, 0, this);
    }

    public void increment() {
        this.current++;
        if(this.current>this.max_image)
            this.current = 0;
    }

    public void setDone(boolean done) {
        this.done = done;
    }

    public boolean isDone() {
        return done;
    }

}

As you can see it is pretty straight forward in approach. The constructor loads the images into an array and sets the done flag to false. The increment method moves us through the images. We've overridden the paint method to draw the image.

Now let's use our JPanel. If you are using Netbeans, go ahead an use the JDialog template, that's what I'll be covering here. In Netbeans add a standard JPanel from the palette and then in the properties window click on the code tab. In the custom creation code add "new RotorPanel()". This replaces the new javax.swing.JPanel that is found in the protected area (which is controlled by the XML file behind the scenes) with this code, which is what we want.

Next in the constructor code right after the initComponents call add the following code.

        this.t = new Thread() {
            @Override
            public void run() {
                RotorPanel p = (RotorPanel) PleaseWaitDialog.this.jPanel1;
                while(!p.isDone()) {
                    p.increment();
                    p.repaint();
                    try { Thread.sleep(65); }
                    catch (InterruptedException ex) {}
                }
                p.repaint();
            }
        };

This creates a thread that will call the increment method to rotate the image and then the repaint method which will update our image. The Thread.sleep(65) call is to sleep 65 ms and then repaint the image, this roughly controls the speed of the animation. Notice that the loop checks the done flag. When you are done and want this thread to die, simply call ((RotorPanel) this.jPanel1).setDone(true);

In 65 ms or less the thread will die because we exit the while loop and the run method of the thread returns. Of course this doesn't mean that you need to stop displaying something, just that you will no longer be rotating the image, hence the check mark image. The actual image doesn't go away until you kill the JDialog.

Pretty simple animation. If you want better control over animation and what-not, I would suggest looking into the timing framework that is located at https://timingframework.dev.java.net/. This framework will allow you have a better control over animating something. However, this is a simple little snippit of code that you can use for simple animations.

Cheers!

Powered by ScribeFire.

Websockets are cool!

I won't go into a lot of detail today, but I tried out serving up some PHP with websockets enabled. Websockets are way cool... I won't go to the end of saying, "OMG!! This will revolutionize the Internetz!!11!!" But I must say that this is will be a big game changer in terms of Internet applications. Combinded with HTML5, web sockets will be the new preferred method for messaging between server and client as opposed to AJAX and similar push technologies.


The best part of Web Sockets is the simple approach they take to passing messages between client and server combined with just how powerful they truly are. If you have ever used callback handlers then web sockets will be a very easy topic for you. You simply register what the web page should be listening for. You web page emits messages to the server and the server emits messages back. On each message received the web page checks what has been registered and the action associated with it.


This has the upshoot of being a write the handler and forget it approach which usually is a disservice to an API, but found that it serves JavaScript quite well.


The only problem will be getting frameworks to start jumping ship from AJAX to Websockets. XML can still be passed using Websockets and most likely that's the way most people will go, but any kind of data can be sent and that includes binary data which tends to be faster and more compact than XML. Most AJAX platforms already present their API as a series of callbacks for people to use in their web pages so Webdevs are already in the right thinking for Websockets.


Another barrier to websockets is the lack of servers that have support for it. The PHP version is still in beta and Apache feels that third parties will fill in the void for them. Jetty (Java server) and a few third party SilverLight stacks provide production grade Websockets at the current moment. The final barrier is the fact that the Websocket standard hasn't been approved as final by IETF, in fact it's still draft. So everything in the standard could change in a moments notice. That alone could keep vendors from adding it to their server. Browser support is Chrome, Opera, and Firefox 4. Basically all the next gen browsers, except our favorite browser to hate IE (including the latest IE 9 build).


All that said Websockets provide a new method of communicating with clients that out matches all currently existing technology and at some point full duplex communications is going to come to all browser and servers, be it websockets or something else down the road. Most likely Websockets will be the winner the biggest question will be in what shape as the standard could change as we all wait for it to become a final standard.

Using Cairo with Gtkmm

Okay we should be all familiar with the Cairo API. If this is the first time you've ever heard of Cairo outside of a reference to Egypt then let me give you a quick peek at Cairo.



Cairo is pretty much the main library used for drawing anything with vectors. It is used everywhere, sort of like SQLite. The website is http://cairographics.org/



In the GNOME trifecta of things, Cairo provides the 2D drawing API, whereas Pango provides the Text Rendering API, and Gtk-Glib provide the toolkit/glue for all the above.



The neat thing about Cairo is that output is not limited to the screen. Backends for Cairo can be written for anything, so things drawn in Cairo can be outputted to an SVG file, OpenGL commands, a printer, or to a Pixbuf for use in a very popular web browser (Firefox anyone).



So today I'm going to use Cairomm (C++ bindings for Cairo) to do some basic drawing. Here is our header file justin_draw.h that defines our DrawingArea.

#ifndef SAMPLE04_JUSTIN
#define SAMPLE04_JUSTIN

#include <gtkmm/drawingarea.h>

class JustinDraw : public Gtk::DrawingArea
{

public:
	JustinDraw();
	virtual ~JustinDraw();
	
protected:
	virtual bool on_expose_event(GdkEventExpose* event);

};

#endif

The only thing of note here is that we are going to define an on_expose_event. This is important because this is the method that is called when the window needs to draw itself. Either because the Window is new, or we've uncovered the window an exposed a part of it that was under another window.




Now let's implement our Gtk::DrawingArea with our justin_draw.cc file:

#include "justin_draw.h"
#include <cairomm/context.h>

JustinDraw::JustinDraw() {}

JustinDraw::~JustinDraw() {}

bool JustinDraw::on_expose_event(GdkEventExpose* event) 
{
	Glib::RefPtr<Gdk::Window> window = get_window();
	
	if (window)
	{
		Gtk::Allocation a = get_allocation();
		const int w = a.get_width();
		const int h = a.get_height();
		
		int xc, yc;
		xc = w/2;
		yc = h/2;
		
		Cairo::RefPtr<Cairo::Context> cr = window->create_cairo_context();
		cr->set_line_width(10.0);
		
		cr->rectangle(event->area.x, event->area.y, event->area.width, event->area.height);
		cr->clip();
		
		cr->set_source_rgb(0.8, 0.0, 0.0);
		cr->move_to(0,0);
		cr->line_to(xc,yc);
		cr->line_to(0,h);
		cr->move_to(xc,yc);
		cr->line_to(w,yc);
		cr->stroke();
	}
	
	return true;
}

Notice a couple of things here before we move on. Drawing an entire screen with Cairo should be done very rarely. Not to say Cairo is slow but there is no need to waste time on drawing. The cr->rectangle(...); cr->clip(); parts allow us to focus on only the part of the window that has changed. Pretty much all code that uses Cairo has something similar to this so it's a good idea to include something like this in you code before you actually do any drawing.




Also notice that we are using a Cairo::RefPtr. Yes Cairo has it's own type of RefPtr's that you must use to hold Cairo related things. You have no idea how much time you can waste using the wrong type of RefPtr.




Finally, our program that uses our new Gtk::DrawingArea. main.cc

#include "justin_draw.h"
#include <gtkmm/main.h>
#include <gtkmm/window.h>

int main(int argc, char** argv)
{
   Gtk::Main kit(argc, argv);

   Gtk::Window win;
   win.set_title("DrawingArea");

   JustinDraw area;
   win.add(area);
   area.show();

   Gtk::Main::run(win);

   return 0;
}

And that's all there is to it! You can hit up basically any manual on Cairo to find all the 2D API commands. It's basically a 1:1 translation between the C and C++ bindings so you shouldn't have any problems there.




Tomorrow I'm going to cover Making a throbbing image in Java, because I'm gotten two emails over the last four days asking how to do that. Till then, Cheers!

Trying out L2TPv3 in Linux 2.6.35.4

So I built me a 2.6.35.4 kernel to try out the new L2TPv3 support offered in this kernel.

L2TPv3 is pretty good and the newest kernel provides awesome RFC 3931 support, but I would advise some people to stick with L2TPv2. Not a lot of 3rd party vendors are there yet and the newest version has a lot of overhead over the wire.

I'm still on the fence about btrfs. I'll give it another six months before I actually change my LVM over.

Oh and by the by. The new kernel improves LVM response by about 5% - 10% depending on setup.

I hate Jennifer Aniston.

This is f'ing funny.


Jennifer Aniston Adopts 33-Year-Old Boyfriend From Africa

A Quick try of Gtkmm

Okay I figure I would give my hand a try at some Gtkmm. The API is pretty much like most curses and Java Windowing framework. So let's do a quick sample.

Let's start with our header file for the Window, we'll call it window1.h

#ifndef WINDOW_1_DEF_H
#define WINDOW_1_DEF_H

#include<gtkmm/window.h>
#include<gtkmm/button.h>
#include<gtkmm/entry.h>
#include<gtkmm/box.h>

class Window1 : public Gtk::Window {

public:

	Window1();
	virtual ~Window1();
	
protected:

	void on_button1_clicked();

private:

	Gtk::Button button1, button2;
	Gtk::Entry entry1;
	Gtk::VBox vbox1;

};

#endif

All of that should explain itself. Basically the object is a Gtk::Window, which is the top level container (widget, whatever you want to call it). We are adding two Gtk::Button, a Gtk::Entry (text entry widget), and a Gtk::VBox which is the layout container.

Now the fun thing about Gtkmm is that you don't have to "new" objects into existence. Instead Gtkmm will handle the memory allocation for you in most cases!! However, if you need to dynamically allocate objects or you need them outside of the class scope then your own your own, unless you use the Gtkmm smart pointer Glib::RefPtr<>, which is basically the same as the std::auto_ptr<> for those of you who have studied standard C++.

Okay let's implement the window, this will be in most logically window1.cc

#include "window1.h"
#include <iostream>
#include<gtkmm/main.h>

Window1::Window1() : button1("Print"), button2("Ouit") {

	set_size_request(200,100);
	set_title("Text Entry Demo");
	
	add(vbox1);

	entry1.set_max_length(25);
	entry1.set_text("Enter something");
	entry1.select_region(0,entry1.get_text_length());
	
	vbox1.add(entry1);

	button1.signal_clicked().connect(sigc::mem_fun(*this,&Window1::on_button1_clicked));
	button2.signal_clicked().connect(sigc::ptr_fun(&Gtk::Main::quit));

	vbox1.add(button1);
	vbox1.add(button2);
	
	show_all();
}

Window1::~Window1() {
	using namespace std;
	cout << "Say goodbye" << endl;
}

void Window1::on_button1_clicked() {
	std::cout << "You have entered: " << entry1.get_text() << std::endl;
}

Okay this one has a couple of things to cover. Like what the heck is the sigc namespace?!

sigc is the library that Gtkmm uses to implement callbacks. A callback is a function or method that is called from another function. Basically the on_click method of your buttons gets called when you click on them. The method basically says, when I'm clicked run ________(insert blank line)________. The callback fills in the blank line.

Now historically there is basically one way to do this in C, but in C++ there must be at least a dozen libraries that do this. I won't get into why this is because that's a much bigger topic.

At anyrate, sigc is the tool that Gtkmm has chosen to implement callbacks. sigc has two ways to add callbacks. mem_fun and ptr_fun, both used here. mem_fun, allows you to call a method and ptr_fun allows you to call a function. Pretty clear cut there. As you can see I've connected the button2's click to the Gtk::Main::quit, which of course does what it says. Quits.

The other button, button1, I've connected to the on_button1_clicked method. This method simply uses standard C++ cout to write information to standard out. You may notice that I use the entry1.get_text() method within the on_button1_clicked() method and that I don't cast it's result to std::string. That's the neatest part of Gtkmm is that it was made to work with the C++ STL so well. Gtkmm already implements the logic needed to cast Glib::ustring (which is what the get_text() wethod returns) to std::string.

The rest of the code is pretty simple to follow.

So now that we have implemented our window we need an application that actually uses it.

I present main.cc

#include<gtkmm/main.h>
#include"window1.h"

int main(int argc, char *argv[]){

	Gtk::Main kit(argc, argv);
	Window1 w;
	Gtk::Main::run(w);

	return 0;
}

This is as basic as you can make an application that uses our window.

The results are here.


Clicking on the Print button outputs the text box on standard out and clicking quit, well quits. As you can see Gtkmm is very much like most other Toolkits, semantics are a little different here and there and you'll use some of the core tools of Gtkmm a little differently but overall you'll easily see how Gtkmm compares to things like SWT, Swing, and QT.

And since I said something about QT, it's worth saying something about it. If you have ever used QT then you know about it's signal/slot system and moc. Well Gtkmm takes the "high road" on this one and uses sigc to implement callbacks in a C++ standard-ish kind of way. The downfall of this, however, is that every callback must be statically typed. This amounts to a lot of double work. If you implement a signal connection in Glade, you must also implement that connection in Gtkmm by importing the widget and then using sigc.

I know this is one of the downfalls of C++'s strong type safety system and name mangling system. QT gets around this with moc but then using moc makes your code non-C++ standard compliant, which I don't think anybody really has a problem with except the people behind Gtkmm.

At anyrate, at risk for getting way off topic, Gtkmm is a neat little wrapper around Gtk+ and you should give it a whirl. You'll be making Gtk+ applications in no time, and best of all is the Gtkmm library works on Windows, Mac, Linux, BSD, and other Unix systems.
Link to Gtkmm

Is it just me?

Does it seem that Colbie Caillat has incredibly "wide" eyes? Is that even a thing? Maybe, I'm just mental?



Oh her song on the radio is a nifty little tune, and she was on the the Next Food Network Star show too. Before that I would have sworn that you were talking about a type of cheese.

Working on a neat project

Usually I have the most fun with design and coding. Rarely do I go back and play with the UI in the sense of having fun with it.

It's just mostly checking if the UI is okay and if there are any bugs/misspellings.

Well I've just got a project that I'm having fun with the UI as well because the interface is a Text based User Interface (TUI, if you are so inclined to use that).

It's cool using JCurses. JCurses is a very loose JNI for the Curses environment, nCurses on Linux. Since it does use JNI that means that you do loose the cross platform compatibility, but JCurses comes with sources and Win32 and Linux x86 binary libraries.

I've been able to compile JCurses for Linux amd64, Mac OSX, and PPA systems. So you should be covered for systems that you may want to run this on.(Note: I don't have access to an ARM chip so I don't know if you can use JCurses there).

The setup at work is to provide a SSH session via RF scanner to our warehouse users, noting new there we've been serving TN-5250 sessions via wireless for the past fifteen years (longer than I've been there).

However, this is the first time that I've actually been calling EJBs from a text based interface. The principal is basically the same, call the remote endpoint from the Java code, present results bark to user.

The fun part is with a text based interface, you really have to concentrate on features and how you present them. A screen full of text is impossible to use effectively, and the more options you present at once the more cluttered the screen appears.

I've found that the best way to break up things is not present all the needed input at once, but instead to take an ask on need approach. So when the next step is to get an EAN or UCC128 code that's what you ask and only that and the options that might effect that.

Also, keyboard functions are limited to basically, TAB, ENTER, F1 through F4, the numbers 0 through 9, and BACKSPACE. Obviously there are no mouse functions.

All of this, limited input, limited screen size, and limited ways of getting the user's attention (Curses can only ring the system bell) really forces you to really think out the UI in a manner that end users usually can't help with.

That's not to say that I never think of the UI for GUIs, but usually we have a company layout and guideline on how our GUIs are created. You simply follow that, get end user feedback, and modify as needed without breaking something.

I'll have to post some examples of JCurses and EJBs soon.

Heading on the road, again.

Well.  I'm heading on the road again.  Travel sucks and double much when it is business travel.  The hope is that this round is my last round for a good bit of time, until next year.

At any rate, I've really got to get back to blogging because I enjoyed it so much.

I've had time in the air to think of some little projects that I'd like to do personally on my system.  I'll have to share them when I'm not in the air.  Also, trains suck.  It never fails that I am delayed twenty minutes going to anywhere by a train crossing.  Just yesterday while going from one building to another I wasted forty-five minutes, the break down is as follows:

1. Rail construction, the construction train was at the crossing on Highway 11.  Wasted 23 minutes.
2. Slow moving train coming back via different route.  Wasted 17 minutes.
3. What the heck! A mostly unused train track is being used to move cargo into a rail-yard. Wasted 9 minutes.

That last one was just to spite me.  I think CSX personally has a vendetta out on me.

Well I'm off.  Cheers!

Where I work trains are a big problem. they can take up to fifteen minutes some times like this guy.
From my phone.

Yeah I know. I've been on the road for company related stuff.

So I've shown how to add security annotations to a pretty vanilla EJB. When you develop EJBs remember to keep them limited in scope. For example, if you have an EJB that handles Inbound orders (placeOrder, reviewOrder, cancelOrder, addToOrder, removeFromOrder, etc...) do not feature creep by having that same EJB handle Outbound orders or worst yet schedule orders in a calendar app.

I cannot tell you the number of times that I've run across an EJB where 30% of the code really belongs in its own EJB unit. For example the calendar app should view Inbound orders as a Collection not as a derived member called SchdOrd (PS use freaking descriptive names! The next guy will not understand that OrdTckChcExc is short for Order Ticket Cache Exchange; nor will that name mean anything to them.) A calendar *HAS A* Collection of Inbound orders makes more sense than A Scheduled Order *IS AN* Inbound Order.

The reason it makes more sense? Just because something is a something else does not mean that the logic for the unit is clarified by the statement. The statement only implies a date an doesn't do a very good job of telling anyone what that date means to anybody. A calendar (thus we get the date concept) has a (okay that tells us something about storage) collection (alrighty this tells us that we are going to be looking at a lot of similar things at once) of Inbound orders.

As you can see the HAS A statement tell more about the underlying logic than the IS A statement. So, more than likely by Justin's 23rd rule of programming, the logic will be easier to implement.

I'm getting off on a tangent here, sorry.

Next post I'll cover using a JAAS callback to implement acustom login dialog and how to handle a failed login, yes you do have to handle those Glassfish will not do it for you.

Cheers!

Had my first in and out burger. awesome.

teenage girl won't stop fighting

teenage girl won't stop fighting mom on aa flight1959. So we're landing in Phoenix. She was hand cuffed! Flight delay!