Reusable code should be well understood and perfectly commented.

The examples below can give an idea about candidates for reusable services and shared data.

• 5.1 REUSABLE SERVICES
  
  Security Services
  
  Taking into account multi-platform implementation this service belongs to the client or presentation side and is implemented differently for different platforms.
  
  For example it's reasonable to use for UNIX systems "whoami" - UNIX system call to return System User ID.
  
  For Windows systems an additional LOGON - dialog window can appear prompting a user for USER ID and PASSWORD. If PASSWORD matches USER ID, this implementation also returns User ID.
  
  
• Cache some data while starting application
  
  This service is used to cache some database tables into memory for multi-user usage. This is a good place to recognize data that can be shared in multi-user application.
  
  
• ExecuteDynamicQuery
  
  This service is executing SQL statement stored dynamically into the Text Data and passed as an argument to the method. It returns result data from database in a format presented by another input argument.

Back To Basic Steps

6. Define the screens and user interface with Human-Computer Interface experts.

Back To Basic Steps

7. Define the date and scope of first deliverable

The main goals are: to prove the basic concepts and to get feedback from the client on the very early stages of the development.

Early client involvement is sometimes crucial for a project success. From another side Object Oriented approach leads to a spiral development process.

Each cycle gives developers more understanding and personal feeling about an application and about new tools, software packages, new environment, that are often used with a new application.

First visible goal achieved is a good point to overview and may be to reinvent all the design. It is beneficial to make this cycle shorter.

This first deliverable can be considered as prototyping effort. Be aware that in many cases the users want to install the prototype into production, even though the design team did not consider it production ready.

Back To Basic Steps

8. Use Style Guidance while coding and review the code regularly. (It also keeps proper communication level for a team). Only well understood and perfectly commented code can be reused.

 
// StyleExample  
 
package its.examples; // Internet Technology School packages
 
import its.gis.ITShape;
import its.util.Tree;
  
/**  
 * A class implementing Java Style Example.  
 * The purpose of the class is … 
 * How to use this class: ...  
 * Example: 
 * @version 0.1 September 10, 1996 
 * @author Jeff.Zhuk@JavaSchool.com 
 */  
 
public class StyleExample extends ITShape { 
    // class data members
    private Tree[] dataTree;  // array of objects
    // .. More data …
    // class methods with JavaDoc headers  
/** 
 * getDataTree(int iIndex) method returns one element of array 
 * @param iIndex element index in the dataTree[] array 
 * @return dataTree if available, return null in other cases 
 */ 
    public Tree getDataTree(int iIndex) {
        if(iIndex < 0 || dataTree == null || dataTree.length < iIndex) { // check first!
            return null;  // to prevent run-time exceptions 
        }
        return dataTree[iIndex]; 
    }
    // more methods ...    
} // end of StyleExample class