CODEWITHSUNDEEP
javaswing
rdonuk
rdonuk

Reputation: 3956

Prevent call a public method from an extended class

I created a custom component which extended from JTextField. I want to prevent calling getText() method from my component. Is there a solution for this problem?

Upvotes: 1

Views: 177

Answers (7)

Jose Sutilo
Jose Sutilo

Reputation: 918

I am not sure of what are you trying to do, but if what you want is that nothing happens when you call getText, just override it and make it return empty string or nothing. It might help if you explain a bit more of what are you after.

EDIT: just read your comment, then do both. @Override and @Deprecated :)

Upvotes: 1

Ale Zalazar
Ale Zalazar

Reputation: 1980

Calling the getText cannot be prevented, as you cannot reduce visibility on override, so you can choose any other option, like returning a null value or throwing an exception like UnsupportedOperationException, explaining in the javadoc, what is the method doing.

The problem with either solution is if you are using a JTextField variable you might be expecting the getText() method to return something else

JTextField textField = new YourTextField();
textField.getText(); //--> might throw an UnsupportedOperationException instead of NullPointerException (as the javadoc says)

Upvotes: 1

arshajii
arshajii

Reputation: 129477

Throw an UnsupportedOperationException in the method. There is no way to disallow calling getText() at compile-time, so the runtime exception is the best alternative.

Additionally, from a documentation standpoint, it would be wise to clearly state (in the Javadocs, presumably) that getText() is not supported by your class. That's really the best warning you can give - it's the responsibility of whoever is using your class to ensure that they fully understand how it works before using it.

Upvotes: 2

Narendra Pathai
Narendra Pathai

Reputation: 41935

You can use UnsupportedOperationException.

@Override
@Deprecated //will allow caller to see that calling this method should not be called
public void someMethod(){
    throw new UnsupportedOperationException("This method is not supported");

}

Upvotes: 2

Tala
Tala

Reputation: 8928

Override it and throw UnsupportedOperationexception in method body or just leave it empty.

Throwing exception will guarantee you that this method is never used since you'll be getting exceptions otherwise and fix.

Upvotes: 2

Konstantin Yovkov
Konstantin Yovkov

Reputation: 62854

Override it, provide a dummy implementation (or just throw UnsupportedOperationException) and mark it as @Deprecated.

Upvotes: 4

rocketboy
rocketboy

Reputation: 9741

Override it with a dummy implementation and add documentation mentioning Not to be used! or throw an exception from inside.

Upvotes: 1

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