Why extend jframe

I already did this once. Edit: The reason for this is that Swing uses an optimized repainting-algorithm, repainting only these components which really need repainting for example, a JTextField after some input or components in front of such ones, as long as they are opaque.

Why shouldn't you extend JFrame and other components? Asked 6 Months ago Answers: 5 Viewed 23 times. A silly example based on your code: import javax. Don't you just have to use: Component. However, the most fundamental underlying reason in the case of suffix trees is a combination of two properties of suffix trees:. The idea here is that the black node on the right is a leaf node, i. But if the text has a suffix aa , then the single character a must also be a suffix.

But there is no way for us to store the information that a suffix ends after the first a , because aa forms one continuous edge of the tree property 1 above. We would have to introduce an intermediate node in which we could store the information, like this:.

But this would be illegal because of property 2: No inner node must exist unless there is a branching point. The problem is solved if we can guarantee that the last character of the text is a character that occurs nowhere else in the entire string. The dollar sign is normally used as a symbol for that. Clearly, if the last character occurs nowhere else, there can't possible be any repetition such as aa , or even a more complex one like abcabc at the end of the string, hence the problem of non-branching inner nodes does not occur.

Obviously, this means we need to introduce an inner node after all, and there are a total of three leaves now. So, to be sure, the advantage of this is not that we save space or anything becomes more efficient. It's just a way to guarantee the two properties above. These properties are important when we prove certain useful characteristics of suffix trees, including the fact that its number of inner nodes is linear in the length of the string you could not prove this if non-branching inner nodes were allowed.

This also means that in practice , you might use different ways of dealing with suffixes that are prefixes of other suffixes, and with non-branching inner nodes. For example, if you use the well-known Ukkonen algorithm to construct the tree, you can do that without appending a unique character to the end; you just have to make sure that at the end, after the final iteration, you put non-branching inner nodes to the end of every implicit suffix i.

But your actual problem: you are sleeping the event dispatcher thread see there. So your idea of sleeping with an event listener is simply the wrong approach. You can't do it this way. You have to re-think your approach there. And the real answer here is: you are lacking basic knowledge of Java. There are numerous examples of callback class code that apply equally well to applications and applets.

Figure HelloWorldApp2 example application. Setting the layout method of the content pane. Instantiating a JBook object. I know I am missing out on some information. Is it like some of the functions of JFrame class are running in the background.

The dollar sign is normally used as a symbol for that. Why do we need to extend JFrame in a swing application? As you can see the only difference is in the setText function. More info on that here. You extend the JPanel class because you need to override the paintComponent function. You're actually changing the behavior of the class by doing this.

You can't do custom painting with the default JPanel implementation. It should end with " The subclass just becomes nuisance in that case. If you are going to extend this class, you might as well take advantage of inheritance. Make a MyButton class to manage the common code and sub-class it for the variable parts:.