Wednesday, September 25

Template Design Pattern in java , Spring

                                           Template Design Pattern in java , Spring







What is Template Pattern

  – Template pattern is about defining the blueprint of the algorithm wherein some of the steps of the implemented in base class and others are deferred for subclass to implement. Spring framework implemented this pattern for many features like, JmsTemplate, JDBCTemplate.



Example:







&lt bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate" scope="prototype" &gt
 &lteq bean &gt



Let's understand Template Design Pattern form core java perspective :





public abstract class ProjectManager {



public final void  collectRequirement(){

   

    System.out.println("requirements are gathered same way in all technology projects. So this could be implemented in baseclass itself and otehr classes can inherit it as it is.");

}



public  abstract void developDesign();



public  abstract void developCode();



public  final void assessQuality(){

    System.out.println("Quality is assessed in same way in all technology projects. So this could be implemented in baseclass itself and otehr classes can inherit it as it is.");

}

public  abstract void deploy();



}


ProjectManager  is abstract class. It has both abstract and implemented methods. Generic methods are implemented here while specific methods are kept abstract for implementing class to define them

Generic method are kept final So that they are not overriden and logic defined in them is used as it is in all implementations.   



  class JavaProjectManager extends ProjectManager {



    @Override

    public void developDesign() {

       

        System.out.println("Desiging is done here in JAVA way");

        // TODO Auto-generated method stub

       

    }



    @Override

    public void developCode() {

       

        System.out.println("Coding is done here in JAVA way");

        // TODO Auto-generated method stub

       

    }



    @Override

    public void deploy() {

       

        System.out.println("Deployment is done here in JAVA way");

        // TODO Auto-generated method stub

       

    }

   

   

}

JavaProjectManager   is implementation of ProjectManager class. It has defined all the specific methods as per the logic spefic to JavaProjectManager class functional requirement

 

  class MicroSoftProjectManager extends ProjectManager {



      @Override

      public void developDesign() {

         

          System.out.println("Desiging is done here in MicroSoft technology way");

          // TODO Auto-generated method stub

         

      }



      @Override

      public void developCode() {

         

          System.out.println("Coding is done here in  MicroSoft technology way");

          // TODO Auto-generated method stub

         

      }



      @Override

      public void deploy() {

         

          System.out.println("Deployment is done here in  MicroSoft technology way");

          // TODO Auto-generated method stub

         

      }

     

     

  }



-->

Similarly MicroSoftProjectManager is implementation of ProjectManager class. It has defined all the specific methods as per the logic spefic to MicroSoftProjectManager class functional requirement


 

  class mainFramesProjectManager extends ProjectManager {



      @Override

      public void developDesign() {

         

          System.out.println("Desiging is done here in mainFrames technology way");

          // TODO Auto-generated method stub

         

      }



      @Override

      public void developCode() {

         

          System.out.println("Coding is done here in  mainFrames technology way");

          // TODO Auto-generated method stub

         

      }



      @Override

      public void deploy() {

         

          System.out.println("Deployment is done here in  mainFrames technology way");

          // TODO Auto-generated method stub

         

      }

     

     

  }

Similarly mainFramesProjectManager is implementation of ProjectManager class. It has defined all the specific methods as per the logic spefic to MicroSoftProjectManager class functional requirement.

Conclusion
So template method is all about defining the execution steps in a contract , provide implementation for all generic methods in contract itself and let the implementation class implement the specific methods. But template or blueprint for all high level steps is covered in abstract class only irrespective of operation is generic or specific.









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