My programming lab Java question 21165 Assume the existence of an interface, Com
ID: 3809637 • Letter: M
Question
My programming lab Java question 21165
Assume the existence of an interface, CommDevice, with the following methods :
transmit: accepts two string parameters and returns nothing
receive: accepts two string parameters and returns a boolean
Define a class , Firewall, that implements the above interface, and has the following members:
a string instance variable , permittedReceiver
a string instance variable , buffer
a constructor that accepts a string parameter that is used to initialize the permittedReceiver variable
an implementation of the transmit method that assigns the first parameter to the destination instance variable and the second to the buffer variable . It also send to System.out the message "Data scheduled for transmission to dest" where dest is replaced by the actual value of the destination string .
an implementation of the receiver method that checks if the first parameter is equal to the permittedReceiver and if so it sets the buffer instance variable to the second parameter and returns true ; otherwise it sets the buffer to the empty string , prints the message "Attempted breach of firewall by " where is replaced by the method 's first parameter , and returns false .
Explanation / Answer
CommDevice.java
public interface CommDevice {
void transmit(String str1,String str2);
boolean receive(String str1,String str2);
}
________________
Firewall.java
public class Firewall implements CommDevice {
//Declaring instance variables
private String permittedReceiver;
private String buffer;
private String destination;
//Parameterized constructor
public Firewall(String permittedReceiver) {
super();
this.permittedReceiver = permittedReceiver;
}
//implementing transmit method
@Override
public void transmit(String str1, String str2) {
destination=str1;
buffer=str2;
System.out.println("Data scheduled for transmission to "+destination);
}
//implementing receive method
@Override
public boolean receive(String str1, String str2) {
if(str1.equals(permittedReceiver))
{
buffer=str2;
return true;
}
else
{
buffer="";
System.out.print ("Attempted breach of firewall by: "+ str1);
return false;
}
}
}
______________________
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