A Tutorial on Using JET for Model to Text transformations

JET is an plug-in for Eclipse that is used to implement a "code generator".
It uses JSP-like template files that can be edited to any kind of source code to which a given model is to be transformed.
For this tutorial we will be transformning a model represented as a set of prolog facts.

The following are useful links to help you get started:

• Install JET
• Create a JET project
• Create a parser for the input model file
• Convert the project to a JET project
• Create the JET Template
• Run the JET template and Generate Source Code

JET plugin

• Run Eclipse with plugin
• Create a JET project (plugin eclipse version)
• Run project (plugin eclipse version)

• In Eclipse go to Install New Software
• In "Work with" enter the following link: http://download.eclipse.org/modeling/m2t/updates/releases/
• Select Java Emitter Templates (JET)
• Click next
• Read the EULA
• Click finish
• Restart eclipse

• Create new Java project
• Add a new file called FruitInput.prolog
• Add the prolog facts to the input file

• Create a new package called "fruit" which will store the necessary data structures
• Create a class file called Fruit
• Add the attributes and methods of the class Fruit

• Create a package called io
• Create a class called InputReader to read and parse the Prolog input file
• Add the code from the InputReader.java file located inside the src folder

• Right click the project folder
• In "New" select "Other"
• Under Java Emitter Templates select "Convert Projects to JET Projects
• Click next
• Select the Fruit folder which is our project folder
• Click finish

• Set the JET code directory
• Right click the JET project folder and select "Properties"
• Scroll to JET Settings
• In this example we are using src, so specify "src" in the "Source Container" option
• Click OK

• Righ-click the "templates" folder
• Go to New and select File
• It is considered good practice to give the template an extension name of the form: typejet, where type is the type of text you will output and jet is "jet". In this case we call it "Fruit2Text.txtjet"
• Ignore the error message that appears, it is a normal error since our template is empty
• Add the body of the template
• We recommend that you watch the video because it has a detailed explanation of the parts of the template

• Right click the project folder
• Create a new package called "test" (you can use any other name you like
• Right click the test package and add a new Class file called "Test"
• Add the corresponding imports and the code to the main. The code is in the src folder in the test file.

• Click the Run button on eclipse
• The source code that was generated will appear in std output since that's what we specified in our Test.java

• Open eclipse
• Download the project to run an instance of eclipse here
.
• File->Import->General->Existing Projects into Workspace
• Select the root: the exampleWizard directory
• Click Finish
• Click the exampleWizard project and click run.

• Select File->New->Other->Prolog to Java Wizards->Create Java Project from Prolog Input
• Click next
• Select the prolog input file from the Fruit project
• Click finish

Convert the project to a JET project (plugin eclipse version)

• Right click the project folder
• In "New" select "Other"
• Under Java Emitter Templates select "Convert Projects to JET Projects
• Click next
• Select the fruit folder which is our project folder
• Click finish
• Right click the project and select Properties
• Select JET Settings
• Type "src" (without quotes) in Source Container
• Click apply then OK
• Delete the folder "generators"

• Open file in templates folder
• Append your own custom code below the header and data initializations

• Save the project and click run