Sunday, 29 September 2013

Chain of responsibility pattern

One of the basic job of a manager is to approve the leave of the superviser


public interface Manager {
      public boolean approveLeave(int noOfDays);
}

class ProjLead implements Manager {
      private String name;
      private Manager manager;

      public ProjLead(String name, Manager manager) {
            super();
            this.name = name;
            this.manager = manager;
      }

      @Override
      public boolean approveLeave(int noOfDays) {

            if (noOfDays < 3) {
                  System.out.println("Leave approved by ProjLead");
                  return true;
            } else {

                  return manager.approveLeave(noOfDays);
            }
      }

}

class SeniorManager implements Manager {

      private String name;
      private Manager manager;

      public SeniorManager(String name, Manager manager) {
            super();
            this.name = name;
            this.manager = manager;
      }

      @Override
      public boolean approveLeave(int noOfDays) {
            if (noOfDays < 7) {
                  System.out.println("Leave approved by SeniorManager");
                  return true;
            } else {
                  return manager.approveLeave(noOfDays);
            }
      }
}

class ProgramManager implements Manager {

      private String name;
      private Manager manager;

      public ProgramManager(String name, Manager manager) {
            super();
            this.name = name;
            this.manager = manager;
      }

      @Override
      public boolean approveLeave(int noOfDays) {
            if (noOfDays < 15) {
                  System.out.println("Leave approved by ProgramManager");
                  return true;
            } else {
                  return manager.approveLeave(noOfDays);
            }
      }
}

class Director implements Manager {

      private String name;
      private Manager manager;

     
      public Director(String name, Manager manager) {
            super();
            this.name = name;
            this.manager = manager;
      }
      @Override
      public boolean approveLeave(int noOfDays) {
            if (noOfDays < 365) {
                  System.out.println("Leave approved by Director");
                  return true;
            } else {
                  return manager.approveLeave(noOfDays);
            }
      }
}

Test the Chain of Responsibility Pattern


      public static void main(String[] args) {

            Director rajaShree = new Director("rajaShree", new Manager() {
                  @Override
                  public boolean approveLeave(int noOfDays) {
                        System.out.println("consulting with Board of Directors");
                        return false;
                  }
            });

            ProgramManager ravindra = new ProgramManager("Ravindra", rajaShree);
            SeniorManager guna = new SeniorManager("guna", ravindra);
            ProjLead lead = new ProjLead("PARIKSHIT", guna);

            lead.approveLeave(400);


      }
Posted by at 1 comment:

Adaptor pattern

There is a company which is does the BCG of persons. They have vast database of blacklisted persons and prisoners etc.

public class OnlineBGCServices {

      private BGCGuide bgcform;

      public OnlineBGCServices(BGCGuide bgcform) {
            super();
            this.bgcform = bgcform;
      }

      public String performBGC() {
            System.out.println("check in  Police Database for fname :"
                        + bgcform.getFname());
            System.out.println("check in  Prisoners Database for lname :"
                        + bgcform.getLname());

            System.out.println(bgcform.getAddressLine1());
            System.out.println(bgcform.getAddressLine2());
            System.out.println(bgcform.getCity());
            System.out.println(bgcform.getState());
            System.out.println(bgcform.getPin());

            // check in Police Database
            // check in Prisoners Database
            // check in BlackList Persons Database
            // ....
            // Return pass/fail
            return null;
      }
}

If someone needs a BGC . he has to call performBGC() method .This  program accepts the person detail object which implements BCGGuide Inteface, as follows:

public interface BGCGuide {

      public String getFname();

      public String getLname();

      public String getDob();

      public String getAddressLine1();

      public String getAddressLine2();

      public String getState();

      public String getCity();

      public String getPin();
}

Following is the simple implementation, as follows:
(Note: This class is not required to run the program)

class BCGform implements BGCGuide {

      private String fname;
      private String lname;
      private String dob;
      private String addressLine1;
      private String addressLine2;
      private String state;
      private String city;
      private String pin;

      public String getFname() {
            return fname;
      }

      public void setFname(String fname) {
            this.fname = fname;
      }

      public String getLname() {
            return lname;
      }

      public void setLname(String lname) {
            this.lname = lname;
      }

      public String getDob() {
            return dob;
      }

      public void setDob(String dob) {
            this.dob = dob;
      }

      public String getAddressLine1() {
            return addressLine1;
      }

      public void setAddressLine1(String addressLine1) {
            this.addressLine1 = addressLine1;
      }

      public String getAddressLine2() {
            return addressLine2;
      }

      public void setAddressLine2(String addressLine2) {
            this.addressLine2 = addressLine2;
      }

      public String getState() {
            return state;
      }

      public void setState(String state) {
            this.state = state;
      }

      public String getCity() {
            return city;
      }

      public void setCity(String city) {
            this.city = city;
      }

      public String getPin() {
            return pin;
      }

      public void setPin(String pin) {
            this.pin = pin;
      }

}

My company XYZ decides to use their services ...In my company we use a data base  customer and we already use a customerDetails Object.Below is bean we are using in our program:

class CustomerDetails {

      private String name;
      private String age;
      private String address;

      public String getName() {
            return name;
      }

      public void setName(String name) {
            this.name = name;
      }

      public String getAge() {
            return age;
      }

      public void setAge(String age) {
            this.age = age;
      }

      public String getAddress() {
            return address;
      }

      public void setAddress(String address) {
            this.address = address;
      }

}

Now, We need to create a adaptor which can convert the CustomerDetails object to BGCGuide Object in order to call there services

We can write a interface customer and  our CustomerDetails object implemets this.

interface Customer {

      public String getName();

      public void setName(String name);

      public String getAge();

      public void setAge(String age);

      public String getAddress();

      public void setAddress(String address);

}

class CustomerDetails implements Customer {

      private String name;
      private String age;
      private String address;

      public String getName() {
            return name;
      }

      public void setName(String name) {
            this.name = name;
      }

      public String getAge() {
            return age;
      }

      public void setAge(String age) {
            this.age = age;
      }

      public String getAddress() {
            return address;
      }

      public void setAddress(String address) {
            this.address = address;
      }

}

  
But we have CustomerDetails Object which implements Customer interface. But To call there service we need to pass an object which implements BGCGuide.

We can write a adaptor which implements BGCGuide will take Customer object . Now We need to create a adaptor which can convert the Customer object to BGCGuide Object.


class MyAdpater implements BGCGuide {

      Customer customer;

      public MyAdpater(Customer customer) {
            super();
            this.customer = customer;
      }

      @Override
      public String getFname() {
            // TODO Auto-generated method stub
            return customer.getName().split(" ")[0];
      }

      @Override
      public String getLname() {
            // TODO Auto-generated method stub
            return customer.getName().split(" ")[1];
      }

      @Override
      public String getDob() {
            // TODO Auto-generated method stub
            return null;
      }

      @Override
      public String getAddressLine1() {
            // TODO Auto-generated method stub
            return customer.getAddress().split(",")[0];
      }

      @Override
      public String getAddressLine2() {
            // TODO Auto-generated method stub
            return customer.getAddress().split(",")[1];
      }

      @Override
      public String getState() {
            // TODO Auto-generated method stub
            return customer.getAddress().split(",")[2];
      }

      @Override
      public String getCity() {
            // TODO Auto-generated method stub
            return customer.getAddress().split(",")[3];
      }

      @Override
      public String getPin() {
            // TODO Auto-generated method stub
            return customer.getAddress().split(",")[4];
      }

}

Finally we can call BGCServices by our old Object as follows :

public class CallBGCServices {

      public static void main(String[] args) {

            Customer customer = new CustomerDetails();
            customer.setName("PARIKSHIT SHARMA");
            customer.setAddress("HOUSE NO 30,RELAABLE WOODS,BANGALORE,KARNATAKA,560006");

            BGCGuide bgcGuide = new MyAdpater(customer);

            OnlineBGCServices bgcServices = new OnlineBGCServices(bgcGuide);

            bgcServices.performBGC();
      }

}
  


Posted by at No comments:
Subscribe to: Comments (Atom)