Designing a Transformation

Here are the steps to start working on our very first Transformation. All you need for starting is to have PDI installed:

1. Open Spoon.From the main menu and navigate to File | New | Transformation.
2. On the left of the screen, under the Design tab, you'll see a tree of Steps. Expand the Input branch by double-clicking on it.

Note that if you work in Mac OS, a single click is enough.

1. Then, left-click on the Data Grid icon and without releasing the button, drag and drop the selected icon to the main canvas. The screen will look like the following screenshot:

Dragging and dropping a step

The dotted grid appeared as a consequence of the changes we made in the options window. Also, note that we changed the preferred language back to English.

1. Double-click on the Data Grid step you just put on the canvas, and fill the Meta tab as follows:

Configuring a metadata tab

1. Now select the Data tab and fill the grid with some names, as in the following screenshot. Then click on OK to close the window:

Filling a Data tab

1. From the Steps tree, double-click on the Scripting branch, click on the User Defined Java Expression icon, and drag and drop it to the main canvas.
2. Put the mouse cursor over the Data Grid step and wait until a tiny toolbar shows up succeeding the Data Grid icon, as shown next:

Mouseover assistance toolbar

1. Click on the output connector (the icon highlighted in the preceding image) and drag it towards the User Defined Java Expression (UDJE) step. A greyed hop is displayed.

1. When the mouse cursor is over the UDJE step, release the button. A link—a hop from now on is created from the Data Grid step to the UDJE step. The screen should look like this:

Connecting steps with a hop

1. Double-click the UDJE icon and fill the grid as shown. Then close the window:

Configuring a UDJE step

Done! We have a draft for our first Transformation. A Data Grid with the names of a list of people, and a script step that builds the hello_message.

Before continuing, let's just add some color note to our work. This is totally optional, but as your work gets more complicated, it's highly recommended that you comment your transformations:

1. Right-click anywhere on the canvas to bring a contextual menu.
2. In the menu, select the New note option. A note editor appears.
3. Type some description, such as Hello, World!. Select the Font style tab and choose some nice font and colors for your note, and then click on OK. This should be the final result:

Hello World Transformation

The final step is to save the work:

1. From the main menu, navigate to Edit | Settings.... A window appears to specify Transformation properties. Fill the Transformation name textbox with a simple name, such as hello world. Fill the Description textbox with a short description, such as My first transformation. Finally, provide a more clear explanation in the Extended description textbox, and then click on OK.

1. From the main menu, navigate to File | Save and save the Transformation in a folder of your choice with the name hello_world.

Next step is to preview the data produced and run the Transformation.