brokermodelnwimpl.java

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package trader.nw;
import trader.*;
import java.util.*;

public class BrokerModelNwImpl implements BrokerModel {
  // ArrayList changeListeners = new ArrayList(10);
  NwClient nwClient;

  /** Creates new BrokerNwImpl */
  public BrokerModelNwImpl(NwClient nwClient) {
    //** 1 Assign the parameter variable nwClient to
    //**   the attribute nwClient
    //**   Hint use this.nwClient
    this.nwClient = nwClient;
  }

// Broker model state change listener registration methods
  /**-----------------------------------------------------------
   * Adds requester to the list of objects to be notified when an
   * object(Customer, Portfolio or Stock) in the broker model 
   * alters state   
   */
  public void addChangeListener(BrokerView bv)
    throws BrokerException {
    //** 1 Leave this method empty for now.   
    //     It will be discussed later during the Advance Multi-Tier
    //     module
  }

// Iteration 1 Customer segment broker model methods
// Customer segment state change methods
  /**----------------------------------------------------------
   * Adds the Customer to the broker model 
   */ 
  public void addCustomer(Customer cust) 
    throws BrokerException {
    Command cmd;
    Object result;
    try {
      cmd = new AddCustomerCommand(cust);
      nwClient.send(cmd);
      cmd = (Command) nwClient.receive();
      result = cmd.getResult();
    } catch(Exception e) {
      throw new BrokerException(e.toString());
    }
  }

  /**-------------------------------------------------------------
   * deletes the customer from the broker model
   */
  public void deleteCustomer(Customer cust)
    throws BrokerException{
    Command cmd;
    Object result;
    try {
      //** 1 Create a DeleteCustomerCommand using cust and
      //**   assign it to cmd
      cmd = new DeleteCustomerCommand(cust);
      //** 2, 3, 4 Remaining 3 lines of code are identical to
      //**         the addCustomer method
      nwClient.send(cmd);
      cmd = (Command) nwClient.receive();
      result = cmd.getResult();
    } catch(Exception e) {
      throw new BrokerException(e.toString());
    }
  }

  /**-------------------------------------------------------------
   * Updates the customer in the broker model
   */
  public void updateCustomer(Customer cust)
    throws BrokerException {
    Command cmd;
    Object result;
    try {
      //** 1 Create a UpdateCustomerCommand using cust and
      //**   assign it to cmd
      cmd = new UpdateCustomerCommand(cust);
      //** 2, 3, 4 Remaining 3 lines of code are identical to
      //**         the addCustomer method
      nwClient.send(cmd);
      cmd = (Command) nwClient.receive();
      result = cmd.getResult();
    } catch(Exception e) {
      throw new BrokerException(e.toString());
    }
  }
  
// Customer segment state query methods
  /**-------------------------------------------------------------
   * Given an id, returns the Customer from the model
   */
  public Customer getCustomer(String id)
    throws BrokerException {
    Command cmd;
    Object result;
    Customer cust = null;
    try {
      //** 1 Create a GetCustomerCommand using id and
      //**   assign it to cmd
      cmd = new GetCustomerCommand(id);
      //** 2, 3, 4 Remaining 3 lines of code are identical to
      //**         the addCustomer method
      nwClient.send(cmd);
      cmd = (Command) nwClient.receive();
      result =  cmd.getResult();
      //** 5 cast result to Customer and assign to cust
      cust = (Customer) result;
    } catch(Exception e) {
      throw new BrokerException(e.toString());
    }
    return cust;
  }

  /**-------------------------------------------------------------
   * Returns all customers in the broker model
   */
  public Customer[] getAllCustomers()
    throws BrokerException{
    Command cmd;
    Object result;
    Customer[] customers = null;
    try {
      //** 1 Create a getAllCustomersCommand and
      //**   assign it to cmd
      cmd = new GetAllCustomersCommand();
      //** 2, 3, 4 Remaining 3 lines of code are identical to
      //**         the addCustomer method
      nwClient.send(cmd);
      cmd = (Command) nwClient.receive();
      result =  cmd.getResult();
      //** 5 cast result to Customer[] and assign to cust
      customers = (Customer[]) result;
    } catch(Exception e) {
      throw new BrokerException(e.toString());
    }
    return customers;
  }
}