Class QueryApplet

java.lang.Object
   |
   +----java.awt.Component
           |
           +----java.awt.Container
                   |
                   +----java.awt.Panel
                           |
                           +----java.applet.Applet
                                   |
                                   +----com.sun.java.swing.JApplet
                                           |
                                           +----QueryApplet

public class QueryApplet

extends JApplet

implements Runnable

QueryApplet()

addLinkMenu()

Delete_Action(ActionEvent)

Opens Client's Query List for Deletion.

Exit_Action(ActionEvent)

Hyperlinks back to the DSRG Homepage

init()

Initializes the GUI.

makeCookie(JSObject)

Sets & returns the client cookie.

makeTableEtc(Object[][], Object[])

Calculates preferred width for JFrame, adds Link Menu if table contains a Home Page column, Makes the table, & shows it in a JFrame.

New_Action(ActionEvent)

Clears the Text Area.

Open_Action(ActionEvent)

Retrieves Client's Saved Queries.

QuerySelected_Action()

Prints the Selected Values to the Text Area.

run()

Runs Thread which Queries Server.

Save_Action(ActionEvent)

Saves Query currently in the Text Area.

SQLHelp_Action(ActionEvent)

Hyperlinks to a web page with an SQL tutorial

submit_server()

Starts Thread to Query Server.

URL_Action()

Uses showDocument(URL) of the Applet Context class to hyperlink to the selected URL

 public QueryApplet()

 public void URL_Action()

Uses showDocument(URL) of the Applet Context class to hyperlink to the selected URL

 public void addLinkMenu()

 public String makeCookie(JSObject win)

Sets & returns the client cookie. Uses the JSObject to call Javascript functions setCookie, etc.

 public void init()

Initializes the GUI. Assigns a cookie (the local host), retrieves a copy of the RMI query interface, draws the GUI components, and defines a convenience class which forwards component ActionEvents to the methods which handle them

Overrides:

init in class Applet

 public void Open_Action(ActionEvent event)

Retrieves Client's Saved Queries. Queries are retrieved using RMI and returned as a List inside a new Frame. If the frame was opened specifically for deletion, multiple selection is possible. (Deletion of a single selection is possible regardless from the frame's menu bar.

 public void QuerySelected_Action()

Prints the Selected Values to the Text Area.

 public void New_Action(ActionEvent event)

Clears the Text Area.

 public void Save_Action(ActionEvent event)

Saves Query currently in the Text Area. Passes the query to the Server using RMI where it is saved in a text file named with the client's cookie.

 public void Delete_Action(ActionEvent event)

Opens Client's Query List for Deletion. This is simply a call to the Open_Action method in deletion mode.

 public void SQLHelp_Action(ActionEvent event)

Hyperlinks to a web page with an SQL tutorial

 public void Exit_Action(ActionEvent event)

Hyperlinks back to the DSRG Homepage

 public void submit_server()

Starts Thread to Query Server. Method captures the SQL query currently showing in the Text area and disposes of the "Open" frame if it hasn't been already.

 public void makeTableEtc(Object Data[][],
                          Object ColumnNames[])

Calculates preferred width for JFrame, adds Link Menu if table contains a Home Page column, Makes the table, & shows it in a JFrame.

 public void run()

Runs Thread which Queries Server. If the call to the server's query method returned no errors in the Return object, a Table is Created with the Query Results and displayed in a Frame; Otherwise the errors are printed one by one to the Text Area. [There is currently no reason to thread the QueryApplet but it has been done for the sake of possible future extensions using animation--and to say we did ;)]