multiple action listeners .setActionCommand Vs. addActionListener(new comboListListener())

[bob von ilten]

Hello All

I have been working on a form that will have multiple buttons and comboboxes. I have worked out two ways to achieve the functionality of multiple listeners for multiple sources, or one listener per source might be a better way of putting it. And I am wondering about the performance / memory usage of each method.

My question is a multipart question.

which method will use more resources as the number of sources grows?

would there be a performance hit for either method?

would either method present a security hazard?

does method one seriously break OOP?

TIA

Method One: use one common listener and the setActionCommand differentiate between sources.

        public void guiAppInterface() {
           
            submitButton = new JButton("Submit");
            submitButton.setActionCommand("submitButton");
            submitButton.addActionListener(this);

            buildingListCb = new JComboBox(listOfBuildings);
            buildingListCb.setSelectedIndex(4);
            buildingListCb.setActionCommand("getSelectedBuilding");
            buildingListCb.addActionListener(this);
            }
            
                    @Override
        public void actionPerformed(ActionEvent event) {
           String actionCommandVar = event.getActionCommand();
           String buttonClickedWas = " ";
           String theActionCommand = " ";
           switch (actionCommandVar) {
               case "submitButton": 
                   buttonClickedWas = "The submit button was clicked";
                   theActionCommand = "The select building is: " + buildingListCb.getSelectedItem();
                   break;
               case "getSelectedBuilding":
                   theActionCommand = "The select building is: " + buildingListCb.getSelectedItem();
                   break;
               default: 
                   theActionCommand = "No matching action command found";
                   break;
           }
          System.out.println(theActionCommand);
        } 

Method Two: use actionListener classes for each object that needs to be heard

   public void guiAppInterface {

            
            submitButton = new JButton("Submit");
            submitButton.addActionListener(new submitButtonListener());


            
            buildingListCb = new JComboBox(listOfBuildings);
            buildingListCb.setSelectedIndex(4);
            buildingListCb.addActionListener(new buildingListCbListener());

        }
        

class buildingListCbListener implements ActionListener {
      @Override
      public void actionPerformed(ActionEvent event){
      System.out.println("The selected building is: " + buildingListCb.getSelectedItem());
      }
     }
        
         class submitButtonListener implements ActionListener {
            @Override
            public void actionPerformed(ActionEvent event){
            System.out.println("The submitted building is: " + buildingListCb.getSelectedItem());
            }
        } 

[Winston Gutkowski]

bob von ilten wrote:I have been working on a form that will have multiple buttons and comboboxes. I have worked out two ways to achieve the functionality of multiple listeners for multiple sources, or one listener per source might be a better way of putting it. And I am wondering about the performance / memory usage of each method.

This sounds to me like a very specific question; so, if you don't mind, I'm going to move it to the relevant forum.

However, I would say this: Don't worry about performance until you KNOW it's an issue; concentrate instead on getting the design right. Chances are, the latter will get you close to the first anyway.

Winston

[Rob Camick]

Use method 2, it is the better design. The creation of one extra class will have no affect that you will be able to measure.

As a general rule, the only time you should use the action command is to handle common functionality. For example maybe you are creating a calculation and you want buttons to enter the digits 0-9. So in this case you can use a common ActionListener and then just use the getActionCommand() method to determine which digit to add to your calculator display. This type of code doesn't require nested if/else or case statements.

[bob von ilten]

Thanks I appreciate the feed back. I will move forward with the individual class design. As to moving it that is fine with me, the main reason I posted it in the beginning forums was that is where I seem to be living lately :-) I also had a rough time finding a simple code example of dealing with multiple sources and single listeners per source. I thought the code example might help some other beginners.

But either way - Thanks Again