LAB01: Introduction to the Lab and brief Java review

Introduction to Service Design and Engineering | University of Trento | Webpage

What's an example of a Service-Oriented Architecture? How does the architecture of the web look like? Where in that architecture is our work going to be centered during these lab sessions? What tools and technologies are we going to use to implement our services?. In this session, we will provide some answers to these questions, in a very brief manner, before passing to the hands-on practice lab in which we will focus on the main characteristics of the programming language we will use during the lab: Java  

Slides & Code

Links: PPT slides | PDF slides | Source code

Guiding Notes

The guiding notes below are a summarized version of what is already on the slides. 

• Start by browsing the introductory first slides of the lesson, introducing the key components in the Architecture of the Web. These slides will give you an idea of where will be placed the focus of our work in lab sessions and what technologies we will be using.  
• Make sure you have downloaded and installed Java in your system . In your terminal/cmd windows, execute

$ java -version

• If the the binary does not exists, follow these instructions to download and install (officially, we will use Java 1.8)

• Revise the slides about Programming in Java, which will give you a very basic overview of the Java programming language.

• Examine, compile and execute the classes of the Example (code is in main repository)

• Try it out!

# Compile
$ javac HealthProfileReader.java

# Execute the program
$ java HealthProfileReader Cristhian Parra
Cristhian Parra is not in the database
$ java HealthProfileReader Pinco Pallino
Pinco Pallino's health profile is: Height=1.72, Weight=85.5

• Exercises
  • In Person.java:
    1. Add a Long attribute to store the person's personId (including accessor methods)
    2. Add a String attribute to store the person's birthdate (including accessor methods, use as date format "YYYY-mm-dd")
    3. Update the constructors accordingly to include these attributes
    4. Update the empty constructor to set the personId to a random number between 1 and 9999.
    5. [optional/advanced] Update the empty constructor to set the birthdate string to a random date between 1950 and the current Year.
  • In HealthProfileReader.java:
    1. Change the database so that the key for each person is the personId
    2. Add the static method createPerson(Long personId, String firstname, String lastname, String birthdate), which creates a new person and adds it to the Database
    3. Add the static method displayHealthProfile(Long personId) , which should lookup the person in the database identified by personId and then print the related healthProfile.
    4. Add the static method updateHealthProfile(Long personId, Double height, Double weight) , which should lookup the person in the database identified by personId and update the related healthProfile with the indicated height and weight
    5. Replace the main program with a version that takes the method name from command-line arguments and to executes it: java HealthProfileReader method_name method_parameters Example: java HealthProfileReader displayHealthProfile 1
• More about Programming in Java
  • Java Cheat Sheet  
  • Java Introductory Tutorial  
  • Other Java Tutorials 
  • Recommended book on learning programming with Java 

Homework: things To Do BEFORE NEXT session

• If you are not familiar with git, follow the tutorial at Try Github (15 minutes) 
• Make sure to install the following tools (especially, make sure that both Tomcat and Axis2 are ready to use, and that both tomcat and ANT binaries are in the PATH (see additional notes below))
  • Git (version 1.8 or higher)
  • Msysgit (for windows)  
  • Ant (version 1.9 or higher, download binaries and make them available on your PATH)  
  • Ivy (version 2.4 or higher, unpack the downloaded zip file wherever you want and copy the ivy jar file into your ant lib directory - ANT_HOME/lib)  
  • Tomcat (version 7.0.39 or higher, follow installation instructions here)  
  • Eclipse for Java EE (any, but it is recommended to download the latest: Luna)  
• Configure your Github account and repository:
  • Create your account in Github (if you haven't)
  • Fork the lab repository to your account (i.e., create a copy of the repository in your github account)

  Go to https://github.com/cdparra/introsde.git.
  Click on "Fork" in the upper right corner of the page
  

  • Clone your fork in your local machine (i.e., download your copy to your machine)

  git clone https://github.com/YOUR_USERNAME/introsde.git
  

  • Add the original repository as a remote, in order to Fetch future updates on the original repository (in case there is any)

  git remote add upstream https://github.com/cdparra/introsde.git
  ```.
  

• Learn the Lab session workflow:
  • Before each session of the Lab, pull the changes from the original repository (i.e., update your local version with changes from the original) 

  git fetch upstream   .
  git merge upstream/master
  

  • On your local repository, inside the folder for the session, create a folder called myworkspace. 
  • Put your personal work in this folder. We will not push changes of our personal workspaces to github. 
    • If, however, you wish to push your changes to github, you will have to edit the .gitignore in the root of your local repo and remove "myworkspace" from it.
    • Then, at the end of each session of work, add your changes to your repository stash

       git add myworkspace
      

    • Commit your changes to your local repository

      git commit -m "my work for labXX"
      

    • Push your changes to your github repository

      git push master
      

Additional notes

Setting up PATH variables: 

In windows: 

• Control Panel -> System -> Advanced tab -> Environment Variables -> System Variables 
• Edit the 'path' variable and append the location of your bin folder onto the existing value (separated by a semicolon). 

PATH = ;C:\Program Files\Java\jdk1.6.0_02�in\;

• Add the following to the file named .bash_profile (or .profile), located in your home directory

export PATH=$PATH:/path/to/your/binary/folder/

Do the same for all other binaries you will need (unless the binary folder is already added automatically) (Ant, Tomcat, etc.) 

Installing Tomcat and Axis2

• First, install tomcat. Go to apache tomcat website.
• Download the zip version of the latest version of Tomcat application manager.
• Unzip it somewhere (e.g. /opt or C:)
• Set environment variables:

    # if you are in unix/linux/mac or you are using msysgit from windows
    export CATALINA_HOME=/opt/apache-tomcat-7.0.39
 
    # windows
    set CATALINA_HOME=C:\apache-tomcat-7.0.39

Observation: for those using msysgit in windows, beware that the "" is a escape character, so you can use either C:\apache-tomcat-7.0.39 or /C/apache-tomcat-7.0.39

• Start the server (to make things easier, add also these binaries to your PATH

    # if you are in unix/linux/mac or you are using msysgit from windows
    $CATALINA_HOME/bin/startup.sh

    # windows
    %CATALINA_HOME%\bin\startup.bat

• Now, go to http://localhost:8080/ and if you see the apache tomcat cat, you are fine.
• Next step: donwload and install axis2. You can either download the war package directly, or download the binary distribution, unzip it somewhere and then build the war. Let's do the second. For this lab session, I downloaded the axis2-1.6.2-bin.zip distribution.

    unzip axis2-1.6.2-bin.zip  
    mv axis2-1.6.2 /opt

Observation: there might be problems with the classpath if you are using only the war distribution. One way of checking exactly what you have in the class path is running ant SOME_EXISTING_TARGET -diagnostics. To avoid potential problems, use the binary distribution.

• Now, you need to enter the weabpp folder in the axis home and create the package war of axis2. How? Using ant ;-)

    cd /opt/axis2-1.6.2/webapp
    ant create.war
    ...
    create.war:
        [war] Building war: /opt/axis2-1.6.2/dist/axis2.war
    ...

• Deploy the war in tomcat. For this, you need to access the tomcat manager in your browser (http://localhost:8080/manager/html)
• By default, Tomcat does not enable admin or manager access. To enable it, you will have to edit the $TOMCAT_HOME/conf/tomcat-users.xml manually by adding the following (or uncommenting if it is there)

    <user username="admin" password="whateverpasswordyouwantiuseadmin" roles="manager-gui,tomcat"/>

• Now, you can access the manager in http://localhost:8080/manager/html and deploy axis war.
• Go to the section Deploy -> WAR file to deploy -> Choose File and select the war you have just created.
• Now that it is deployed, you can open axis2

    Follow this link http://localhost:8080/axis2. 

• Should show you a page with 3 links: services, validate, administration. Open validate.

    Follow the link http://localhost:8080/axis2/axis2-web/HappyAxis.jsp

• It should should show you a HappyAxis page with the list of needed libraries and their status (if they are or not in your system). If the Happy Axis page is coming with GREEN color then it means that axis2 is successfully deployed.