Builder Pattern Implementation

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Use Case Scenario Description

Simulate the working of a shop where the clients can request different types of laptops like - Gaming laptop, Personal laptop and Developer laptop.

The application constraints are:

The process involved in creating the different types of laptops should be similar.

The client should be unaware of the different parts/components that are used to assemble the laptop.

Based on the type of laptop requested an appropriate shop technician instance should be created who would follow a process to pick the right parts and assemble the laptop.

Only after all the components have been set properly and the laptop is ready the laptop should be given to the client.

Flexibility

This implementation is flexible to support new types of Laptops without a lot of code modification. I have used Builder pattern in my implementation.Whenever a new type of Laptop is to be added, we just have to make a new class corresponding to it and make sure that this new class implements all the methods specified in the LaptopBuilder interface.

This makes the design very flexible to changes.

Simplicity and Understability

I have implemented logging to demonstrate the working of my implementation. In case if something goes wrong we can refer to the logs. This is useful to simulate the order in which the parts were selected to assemble the laptop. This was especially helpful while testing the logic of the system. Overall the implemenntation of any method can also be understood from the comments.

Avoiding code duplication

The director instances can use the different concrete builders to obtain different representation from the similar components. Most instance variables have well defined Getters and Setters hence they can be accessed once the class is instantiated. Hence a lot of code duplication was avoided by using the Builder Pattern.

How to compile the project

We use Apache Maven to compile and run this project.

You need to install Apache Maven (https://maven.apache.org/) on your system.

Type on the command line:

mvn clean compile

How to create a binary runnable package

mvn clean compile assembly:single

How to run

mvn -q clean compile exec:java -Dexec.executable="edu.bu.met.cs665.Shop" -Dlog4j.configuration="file:log4j.properties"

We recommand the above command for running the project.

Alternativly, you can run the following command. It will generate a single jar file with all of the dependencies.

mvn clean compile assembly:single

java -Dlog4j.configuration=file:log4j.properties -classpath ./target/JavaProjectTemplate-1.0-SNAPSHOT-jar-with-dependencies.jar  edu.bu.met.cs665.Shop

Run all the unit test classes.

mvn clean compile test

Using Findbugs

To see bug detail using the Findbugs GUI, use the following command "mvn findbugs:gui"

Or you can create a XML report by using

mvn findbugs:gui 

or

mvn findbugs:findbugs

For more info about FindBugs see

http://findbugs.sourceforge.net/

And about Maven Findbug plugin see https://gleclaire.github.io/findbugs-maven-plugin/index.html

You can install Findbugs Eclipse Plugin

http://findbugs.sourceforge.net/manual/eclipse.html

SpotBugs https://spotbugs.github.io/ is the spiritual successor of FindBugs.

Run Checkstyle

CheckStyle code styling configuration files are in config/ directory. Maven checkstyle plugin is set to use google code style. You can change it to other styles like sun checkstyle.

To analyze this example using CheckStyle run

mvn checkstyle:check

This will generate a report in XML format

target/checkstyle-checker.xml
target/checkstyle-result.xml

and the following command will generate a report in HTML format that you can open it using a Web browser.

mvn checkstyle:checkstyle

target/site/checkstyle.html

Generate coveralls:report

mvn -DrepoToken=YOUR-REPO-TOCKEN-ON-COVERALLS  cobertura:cobertura coveralls:report