Transcript Code Generation Tools

Code generation tools
Galit Keret
Moti Zviling
Contents

Why is code generation technology required?

What is it and what kind of a solution it offers?

CGN – Code generation network

Features of a good code generation tool

Related terminology

Active and passive code generation

RAD and CASE

Code generation products

How to find the right tool for your needs?

Code generation models


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Code samples for each model

Partial Products list for each model
So why is it not vastly used?
Demo
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Sometimes it’s a bummer to be a
software engineer…
Ever felt like this?
Writing thousands and thousands of
tedious code, your deadline is
impossible to reach (as always), and in
the end you found yourself facing
dozens of bugs and worse than that you discover your application’s
performance is poor…
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Some scary facts about software world
(from OOD course)



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84% of software projects are not on time
31% of software projects never complete
~60% of completed code is never used
~200 Billion $ a year lost to software bugs
Let’s say this in words:
 Most software is buggy, unstable and insecure
 A lot of software is totally unusable
Introducing a new concept:
Code generation tools.
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What is “Code generation”?

Strictly speaking: Code generation is the
technique of building code not manually but
using other programs.
 You simply need to define a specification of
abstract requirements to the tool.
Using templates, it will then build one or more
output files based on your requirements .
 Saves you the need to write the tedious parts
or parts that are not in the areas of your
expertise.
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CGN – Code generation network
Covers all aspects of code generation:
Includes interviews with engineers using
and building code generators as well as
articles, tutorials and example code.
Holds an alphabetically database of
generators and a list of books about
code generation.
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Features of a good code generation tool


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Quality - Generated code always increases in quality over time
because as bugs or shortcomings are found they can be fixed in
the code templates and applied across the code base.
Consistency - Generated APIs are consistent in class structure,
variable naming and signatures.
Productivity –
 Generators build code in a fraction of the time that it takes an
engineer to produce the equivalent amount of code.
 Generators allow the engineer to offload grunt-work so that
they can concentrate on tasks that require more creative
solutions.
 Save testing time – don’t need to test the generated code.
Abstraction - Generators provide a layer of abstraction between
the design and the code base. The definition files used by these
generators hold the schema and business rules for your
application in a declarative form.
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Related terminology:
Active and passive code generators


There are two types of code generators:
 Active generators - intended to be run multiple
times on the same output code as the design of the
input or generator changes.
 Passive generators - create the initial code, and
then it is the responsibility of the developer to
maintain it (example: a wizard).
Although both types will provide an initial boost to
productivity, active generation is superior , because in
this type of code generation the code is maintained
and bugs in the templates can be rolled out across the
whole code base.
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Active and passive code generation workflow
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The standard workflow in software engineering:
edit-compile-test.
The workflow cycle of a passive generator:
run the generator, then follow the edit-compile-test
cycle repeatedly on the code created by the generator.
The workflow cycle of an active generator:
run the generator, then compile, edit and test the
output.
Found a problem in the generated code?
alter the templates or input of the generator and regenerate.
Found a problem in the hand-written code portion?
follow the standard edit-compile-test workflow.
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Related terminology:
RAD and CASE
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CASE - computer assisted software engineering
 Similar to code generation tools.
 The analyst could define the business logic using
visual tools and a generator would build all of the
application code.
RAD – Rapid application development
 An approach to building computer systems which
combines CG/CASE tools and techniques, userdriven prototyping, and stringent project delivery
time limits.
 The typical RAD project delivers a fully functional
computer system in just a few days!
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CASE v. Code generation tools
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In both methods a generator build an
application from an abstract description.
 The difference is in the approach:
CASE tools attempt to replace trained
engineers with tools that do the same work.
CG tools are built by engineers for themselves
– to make their life easier.
 Both tools can end up in the same place!
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Some facts about code generation
products
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There are almost 200 code generation tools in
the code generation network, and this list is far
from being complete.
Yet only few engineers know about code
generators and fewer still have used them.
CGT claims that the reason for this is lack of
advertisement and clear information about it.
 The most common uses of code generators
are database access and UI generators.
 There are more generators written for Java
users than all of the other technologies
combined.
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Finding the right code generator
for your needs

The code generation decision tree will help
you look for the right generation tool for your
project.
 If none of the generators listed address your
needs you can use one of the ‘custom code
generators’ which supports scripting in a
variety of languages.
 Failing that, you can always write your own
generator…(just be sure to first read the DO IT
YOURSELF section at the Code generation
network)
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Code generation models
1.
2.
3.
4.
5.
6.
Code munger
Inline code expander
Mixed code generator
Partial class generator
Tier generator
Domain language
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Code Munger Model
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The most common form of code generators
The code munger reads the source file,
analyzes it, and creates one or more output
files.
 Processing Flow:
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A code munger model example –
a translator
A translator takes a code written in some programming language
and translates it to a code written in some other language.
 The input and output of a ‘C to Java’ translator will look like this:
output
Input

class Wrapper {
char c;
int x;
char c;
int foo(int y, char d)
int x;
{
int foo(int y, char d)
{
int i;
for (i=0; i<3; i=i+1)
int i;
{ x=3; y=5; }
for (i = 0; i < 3; i = i + 1)
{ x = 3; y = 5; }
}
}
}
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Some Code Munger Model products
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JavaDoc: reads and parses the
comments within a Java source code
file, then creates HTML documentation.
very easy to learn and use.
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ANTLR: helps to build programming
language translator. Generates recognizers
in Java, C++, C#, and soon Python.
C2J: a C/C++ to Java translator.
The generated code is not understandable!

Jazillian: a C to Java translator.
The generated code is natural (as if it was written by hand),
but there are some minor translation bugs.
(presented in demo)
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Inline Code Expander Model - overview
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It starts with designing a new language. Usually this
new language is an existing language with some
syntax extensions. The inline code expander is then
used to turn this language into production code in a
high level language.
Processing Flow:

The input is a source file for a new
language.
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The output is a source file in a high
level language suitable for
compilation.
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An Inline Code Expander example:
C with embedded SQL
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Embedded SQL is a method of combining the
computing power of a high-level language like Java
or C/C++ and the database manipulation capabilities
of SQL. It allows you to execute any SQL statement
from an application program.
In the example code, SQL is embedded into C source
code files using special markup. These hybrid C files
are given their own extension, such as '.sqlc‘:
// main.sqlc
int main( int argc, char *argv[] )
{
< SQL select * from users >
return 0;
}
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An Inline Code Expander example - continued
After running the generator the
corresponding created C file will look like
this:
#include "db.h“
int main( int argc, char *argv[] )
{
DBHandle *db_handle = db_connect();
DBQueryDara *db_data = db_db_query( db_handle, "select * from users" );
for( int record = 0; record < db_data->length; record++ )
{ // fetch and process data }
return 0;
}
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Some Inline Code Expander products
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Pro*C (Oracle) - Allows embedding of
SQL into C source code. It takes some time to learn the
Pro*C syntax, which is not intuitive, and it’s difficult to use in complex operations
and also the generated code is not object oriented. Only 2 links in Google refer to
this technology which means it’s not a success story.
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SQLJ (Oracle) - Allows embedding of
SQL into Java source code.
a more intuitive syntax and some what more object-oriented approach to the
Pro*C way of embedding SQL statements in programs, but still the
recommendation is to use it only when the data being mapped is quite simple
(don’t use it in case of multiple mappings of Java objects to tables and vice versa)
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Mixed Code Generator Model

The same processing flow as the Inline Code
Expander, except that the input file is a real
source file that can be compiled and run.
 This technique can be used for a variety of
purposes:
 Building the user interface glue code to
attach variables to user interface controls.
 Building test case code from test case data
stored in comments.
 Creating database access code from
access specification stored in comments.
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Mixed Code Generator : example
an example input file for the SQL handling mixed
code generator:
#include "db.h"
int main( int argc, char *argv[] )
Mixed Code Generator
{
// SQL: select * from users
// SQL end
return 0; }
After running the generator it will fill the space between
the comments with an implementation of the requested
SQL statement (it will look like the output showed in the
previous example). The comments are preserved so that
if the generator is run again, the same replacement can
be done.
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Mixed Code Generators v. Inline Code Expanders

a major disadvantage of an Inline Code
Expander is that the debugging is done
against the output file. This means that you
need to integrate any changes you make to
the output code back into the input file after
debugging is finished.
 In mixed code generation model the source
code can be debugged directly (the input and
output files are the same). They can also
integrate nicely into IDEs as external tools.
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Mixed code generators v. Other generators

Most generators build or manage entire files or
even generate a whole application tier.
 This creates a barrier to entry of using code
generators on existing products which don't
take well the fact of having large sections of
code replaced completely.
 Mixed code generation tools provide genuine
aid in developing both new and existing
applications, by enabling code generation for
multiple small code fragments within a single
file or distributed throughout multiple files.
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Some Mixed Code Generator products
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Codify - A code generator that integrates
into the Visual Studio .NET framework
which can generate multiple code
fragments within a single file.
For example: can generate the code for
get/set methods of class properties.
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Partial Class Generator Model
A partial class generator builds a set of
base classes that are used as a platform
to build the production classes.
 The base classes are designed to do the
majority of the low level work of the
completed class, leaving the derived
class free to override specific behaviors
on a case-by-case basis.

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Partial Class Generator – processing flow
The generator reads a definition file, then using a set of templates,
builds one or more base classes.
These base classes are then augmented with derived classes
All of the classes are then compiled together to build the final
product.
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Partial class generator –
database access classes
An typical use of a partial class
generator is to build database access
classes.
 The generator builds the basic
persistence code for each class and its
fields. The derived classes are
responsible for any custom behavior .

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Some Partial Class Generator products
Coder – a toolkit that
supports the creation of code
generators
 Codegen - an open source (LGPL),
UML Class Diagram to C#, Java
and VB.NET code generation
framework.
 Expert
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Tier Generator Model

A tier generator builds and maintains an entire
tier within an application.

Processing flow:
The tier generator takes an abstract definition file and
using a set of templates builds one or more output files
that constitute all of the functionality for an entire tier
of the application.
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Example of a tier generation tool
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a good database/web application is built as a
n-tiers application (e.g., database access,
business logic and user interface).
 Most of the tier generators builds the database
access tier or the user interface tier of such
applications.
 There are so many CG tools that generate the
database access tier for database applications
that they even got a special name:
O/R mapping tools (“Object to Relational
mapping”)
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Tier generation example (continued)
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O/R mapping tool - a code generation tool that connects
to your database and reads its schema, then lets you
map objects to database tables and views, specify
insert, update, load, and delete operations, queries and
stored procedure calls, as methods to these objects.
It also lets you define the relationships between objects
(one-to-one, one-to-many, etc.) based on relationships
between tables in the database.
It then generates fully working persistence objects code
for you.
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Tier generation example (continued)
An O/R mapping tool processing flow:
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Tier generation example (continued)
Below is an example of code a user will write, using
an O/R mapping tool:
try {
Employees objInfo = new Employees();
EmployeesFactory objFactory = new EmployeesFactory();
objInfo.EmployeeID = EmployeeID;
objFactory.Load(objInfo);
// code here to use the “objInfo” object
}
catch(Exception ex) {
// code here to handle the exception
return;
}
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Some Tier generation products

Tier developper – an O/R mapping tool that runs on
.NET platform. Very easy to learn and use.
Excellent demos are available on site.
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XLInesoft ASPRunner Professional –
Creates a set of ASP pages to access
and modify MS Access, MS SQL,
Oracle and other databases. Also very easy to learn
and use but has less configuration options and generates
less languages than ‘Tier developper’.

(presented in demo)
BrightSword™ Designer –
build database-driven web applications in ASP,
ASP.NET, JSP and PHP.
Not user friendly as ASPRunner and the trial version crashes.
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Tier generators Vs. Partial class
generators
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Tier generators are harder to write:
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But tier generators are better:
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Tier generator maintains all of the tier’s code, including all
edge cases.
Partial class generator follows the 80/20 rule: it handles 80%
of the standard cases, and the rest 20% is handled by
customized derived classes.
Better business rules abstraction
Easy to port the application to other platforms
The result: generators often start as partial
class generators. As the code solidifies and
the problem domain becomes better
understood the 20% become smaller and
smaller until the whole tier is auto-generated.
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A domain specific language model
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The tool provides the user with a new language that
has types, syntax and operations that map directly to
the concepts of the user’s domain.

Examples: Mathematica and Matlab
These languages make it easy for the scientist to
represent constructs that are difficult to code in
general purpose languages, such as multi-dimensional
matrix math.

Another example, although not as clean as the
pervious example because it obligates the user to
describe her domain in terms of classes and
relationships between classes is MDA.
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MDA - Model-Driven Architecture

MDA is a set of related standards specified by
the Object Management Group (OMG).
 These standards: UML, XMI, MOF, OCL, CWM
are used to turn a model written in Unified
Modeling Language [UML] to engineering
artifacts in the form of source code, or
documentation.
 MDA is targeted mainly at the professional
production languages: Java, C#, and C++.
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MDA : the 3 tiers model
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The MDA 3-tiers model for code generation:
Platform independent
model (PIM)

Platform specific
model (PSM)
Templates
Code
How is it done? Using XMI
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XMI is an XML based export standard for UML models.
The platform-independent UML model is maintained in the Meta
Object Facility (MOF) repository and exported via XMI to the
generator.
The generator then reads the XMI and applies transformations
to it to create the platform-specific model. This model is then
used as input to a set of templates which build the output code.
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MDA processing flow
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MDA processing flow and the 3 tiers model
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Some MDA products
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IBM Rational Rose - a popular UML
to C/C++ generator. Undo/redo operations on
the UML diagrams are not supported.

BridgePoint – a UML to C/C++
generator. A good product but no free trial version.
BridgePoint

UModel by Altova – a UML to Java and
vice versa generator. Very easy to learn and
use, supports undo/redo operations
(presented in demo)
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If it’s so great than why aren’t we using it?
8 traditional arguments against using code generation:
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Why not just use cut and paste?
Code generation doesn’t work on existing code bases.
The quality of the output code is bad.
Generators are too complex.
Generators are great in the beginning, but they are never
maintained (Engineers will ignore the 'do not edit'
comments).
My application isn't complex enough for generation.
My application is too complex for generation.
Code generation will eat my job
.
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Summary of tested products
Product
Link
Model
Application
Type
Target
Language
Bottom
Line
Jazillian
Code
Munger
a C to Java translator
Java
Some minor
translation bugs
C2J
Code
Munger
a C to Java translator
Java
JavaDoc
Code
Munger
creates HTML
documentation
for Java APIs
Java
Inline Code
Expander
DB access code:
embedding of SQL
into C
Pro*C
(Oracle)
Legend:
Recommended
C
Worth trying
code generation tools
Generates strange
code!
The syntax is not
intuitive (much
difficult to learn
than SQLJ)
don’t try
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Products summary (continued)
Product
Link
Model
Application
Type
SQLJ
(Oracle)
Inline Code
Expander
DB access code:
Embedding of SQL
into Java
Codify
Mixed Code
Generator
Codegen
Partial class
generator
Tier
developper
Tier generator
Any code.
Integrates into Visual
Studio .NET
Target
Language
Bottom
Line
Java
good only when the
data being mapped is
quite simple
C++ C# Java
Built in templates are
for get/set methods
only. Write other
templates you’ll need
by using the templates
editor
C# Java VB.NET
An open source
so worth trying but was
not tested by us
Any code.
UML to C#, Java and
VB.NET source code
DB access + UI
code:
an O/R mapping tool
that runs on .NET
platform.
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VB.NET SQL A
SP.NET Visual
Basic C# C++
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Products summary (continued)
Product
Link
ASPRunner
Professional
Model
Tier
generator
BrightSword™
Designer
Tier
generator
IBM Rational
Rose
MDA
generator
UModel by
Altova
MDA
generator
Application
Type
Target
Language
Bottom
Line
DB access + UI code:
build database-driven
web applications
ASP ASP.NET
Supports
only ASP
output
DB access + UI code:
build database-driven
web applications
VB.NET PHP
ASP.NET
ASP JSP C#
Trial version
crashes
Any code:
UML to C/C++
generator
C/C++
No undo/
redo
operations
Any code:
UML to Java
generator
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Java
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Demo Part
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Types of code generation

A reminder:
Code generators are programs that
automatically generate high level code
(e.g. C, C++, C#, Java, Perl, Python, Ruby, etc.).

List of code generation applications:
http://www.codegeneration.net/generators.php
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Code generation – decision tree
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ASPRunnerPro
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ASPRunnerPro - description


ASPrunnerPro is a database management tool that
provides easy access and manipulation possibilities
for any database on the Web. Designed to suit all
users from beginners to experienced developers,
ASPRunnerPro creates Active Server Pages (ASP)
enabling users to search, edit, delete and add data to
the Oracle, SQL Server, MS Access, DB2, or MySQL
databases.
Sample generated ASP pages:
http://www.xlinesoft.com/asprunnerpro/screenshots.htm

Download a trial version from:
http://www.xlinesoft.com/asprunnerpro/download.htm
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ASPRunnerPro - features

Product Features:
 Easy to use wizard-like interface.
 Generates 100% pure ASP code.
 Numerous search modes.
 Add, view, edit, copy and delete pages. The ASPRunner wizard
 Built-in FTP Client to upload ASP
pages to the Web server.
 User self-register page, password reminder,
change password pages.
 Multilingual templates. Ability to choose language
while logging in.
 Creates password protected ASP pages.
 A very simple installation.
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Jazillian – C to java translator

http://www.jazillian.com/trial.html
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Jazillian – Description

Jazillian takes the C source files that
you provide and applies a series of
transformation rules to convert various C
constructs and patterns into their Java
equivalents.
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Jazillian – Example1

Example 1: "Hello, World"
The classic C program:
 main(char *argv[], int argc)
 { printf("Hello, world!\n"); }


Becomes the classic Java program:
public class Hello { public static void main(String[] args) {
System.out.println("Hello, world!"); } }


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


In this case, Jazillian applied the following "rules":
Assuming the file was called "hello.c", The Java file "Hello.java" was created.
The signature of the main() function was changed.
The printf() call was changed to a System.out.println() call.
The function was enclosed inside a new "Hello" class.
The key to Jazillian is that it produces not just correct, but reasonable Java
code. Each of the three "rules" applied here illustrates this.
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UModel-Altova - description

UModel™ 2005 is an affordable UML modeling
application with a rich visual interface and
superior usability features to help level the UML
learning curve, and includes many high-end
functions to empower users with the most
practical aspects of the UML 2.0 specification.
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UModel-Altova - features

UModel™ 2005 supports:
·context sensitive entry helpers
·syntax coloring in diagrams
·customizable design elements
·unlimited Undo and Redo
·sophisticated Java code generation from models
·reverse engineering of existing Java source code
·complete round-trip processing allowing code, and model merging
These capabilities allow developers, including those new to software
modeling, to quickly leverage UML to enhance productivity and
maximize their results.
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Elevator Problem demo

Problem description: control elevators in a
building with m floors.
 Constrains: Each elevator has a set of m buttons
 Each button is illuminated when pressed
(moving to the desired floor)
 Illumination is canceled when elevator visits the
corresponding floor.
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Elevator Problem (continued)

Each floor (except first and top) has 2 buttons:
request up-elevator, request down-elevator
 Buttons are illuminated when pressed
 Illumination is canceled when elevator visits the
floor and then moves in the desired direction.
 When elevator has no request, it remains at its
current floor with its doors closed.
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Elevator Problem (continued)

Analysis in UML (unified modeling language)
 UML: specifies semantics and notation but no
process is currently defined.
 We will show:





Use case diagrams
Class diagrams
Collaboration diagrams
(sequence and state diagrams will not be shown)
Generating code from the above diagrams
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Use Case Diagrams














Generalized description of how a system will be used
Provided an overview of the intended functionality of the system
Understandable by beginners and professionals
Elevator scenario is extracted as follows:
1. Passenger pressed floor button
2. Elevator system detects floor button pressed
3. Elevator moves to the floor
4. Elevator doors open
5. Passenger gets in and presses elevator button
6. Elevator doors closes
7. Elevator moves to required floor
8. Elevator doors open
9. Passenger gets out
10. Elevator doors closes
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Class diagrams

Static structure of the object
 Internal structure
 Relationships among objects
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More Tools in a Nutshell
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Camino – Tier generation
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Camino – Tier generation
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Integrated Support for Struts-Tiles
Camino allows you to manage multiple Tiles definition
XML files for multiple Struts sub-apps/modules.
Document Generation Wizard
With a push of button, you can easily create design
documents of your web-application in HTML.
Based on the configurations of the applications and the
annotations you added, Camino automatically generates
the index pages, hyperlinks for all the cross-references,
storyboard images and description pages.
Application Model Verifier
Catch hard-to-find mistakes and verify referential integrity
of the configurations of your applications as early as
possible.
Camino Pro verifies all of your code artifacts and notifies
you errors and potential errors.
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Camino – Integrated Support for
Struts-Tiles
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Camino – Document Generation
Wizard
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Camino – Application
Model Verifier
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AndroMDA – Tier generation

Target – any code
 Targets – JAVA
 Description: reads a UML model (exported
as XML) and creates Java code.
 Home page: http://www.andromda.org/
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Albatross – Tier generation







Target – any code
Targets – Asp.net, C#, SQL, VB.net
Description: Build wizards to generate the code.
Albatross has a script language to generate code.
Input formats: Source Code, XML, Custom
Allowed customization: Code Generation templates,
Type of files generated, Input format, Output
format, Input processing.
Home page: Http://www.thecodegenerator.com
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Bridge Point – Tier generation

Target – Full web application
 Implementation language - C
 Targets: C & C++
 Description: An MDA model compiler that
builds C and C++ from UML models.

Home page: http://www.projtech.com
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Modelisoft – Tier generation

Target – Full web application
 Implementation language - C
 Targets: Database,C#
 Description: Able to make design decisions
controlled by UML stereotypes. In
conjunction with the Modelisoft AutoGUI
library, it can produce a Windows
application allowing browsing the model

Home page: http://www.modelisoft.com
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JavaDoc – a code munger example
The most common form of code generators.
 A code munger processes one or more source
code files and generates some number of
corresponding output files. JavaDoc is an
example of a code munger. JavaDoc reads and
parses the comments within a Java source code
file, then creates HTML documentation from the
comments using a set of templates.

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The processing flow of JavaDoc Code
munging:

The Java files come into the generator, the comments are parsed
and the output HTML files are created using a set of
templates
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Article links
Many ideas and phrases included in this presentation
and in the web site link were originated in the following
articles/links:
 Code Generator Models
 FAQs about code generations
 One page guide to code generators
 MDA generation
 Generating Java and XML Using StringTemplate
 Language Translation Using ANTLR and
StringTemplate
 Tool libraries for a code generation tool developer
 Top 10 Must Have Features in O/R Mapping Tools
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Thank You
The END!
Questions ?
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