Java InstantCode. Developing Applications Using Java NIO

To create the client-server application using RMI, you need to create a remote interface that declares the business logic of the application. The FileRemote.java file is a remote interface for the File Download application that defines the prototypes of the methods implemented by the FileRemoteImpl.java file.

Listing 3-1 shows the contents of the FileRemote.java file:

Listing 3-1: The FileRemote.java File

/* Imports java.rmi package classes. */ import java.rmi.Remote; import java.rmi.RemoteException; /* Imports java.util package classes. */ import java.util.Vector; /* Interface FileRemote - This interface declares the remote methods. Methods: downloadFile() - Downloads the file from a remote location. displayList() - Displays the list of files stored in the server to the client. */ public interface FileRemote extends Remote { /* Declares downloadFile() method. */ public byte[] downloadFile(String filename) throws RemoteException; /* Declares displayList() method. */ public Vector displayList() throws RemoteException; }

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In the above code:

• The FileRemote interface defines the methods to perform various operations of the File Download application. These methods include displayList() and downloadFile().

• The displayList() method displays the file list to the client machine.

• The downloadFile() method downloads the selected file from the remote machine.