Java addActionListener, multiple instance is occurring

Question

When i try to perform action for comboBox_0, it wil print "red" and change selected item on comboBox_1 as "apple", however it will also generate action event for comboBox_1 and will also print "blue".

How can i perform this so the program will not see changing comboBox_1 item as generating action event. i dont need it to print "blue", only print "red" and change to "apple".

Is there a way for java to differentiate between user conducted action vs the program itself?

Sorry, i'm new to this field and i cant check source where they discuss about ActionEvents.

here's the example:

public void actionPerformed(ActionEvent e) 
{
    if(e.getSource()==comboBox_0)
    {
        System.out.println("red");
        comboBox_1.setSelectedItem("apple");
    }
    else if(e.getSource()==comboBox_1)
    {   
        System.out.println("blue");
    }
    else if(e.getSource()==comboBox_2)
    {
        System.out.println("green");
    }
}

Answer 1

You are raising an event, but at the same time you don't want to use it. Enter the flag into your program. Use this:

private boolean flag = false;
public void actionPerformed(ActionEvent e)
{
    if(e.getSource()==comboBox_0)
    {
        System.out.println("red");
        comboBox_1.setSelectedItem("apple");
        flag = true;
    }
    else if(e.getSource()==comboBox_1)
    {
        if(flag){
            flag = false;
            return;
        }
        System.out.println("blue");
    }
    else if(e.getSource()==comboBox_2)
    {
        System.out.println("green");
    }
}

Unfortunately, it is not possible to distinguish the event source (software or user-defined). But it is not necessary. If there were such an implementation, it would in any case be reduced to a"flag". You can use boolean or Emun as the flag.