obj instanceof (String [] )

[Igor Ko]

Hi !
I wish to write the function where argument
can be String or String [] ( like C printf ;-) )
void function(Object obj){
if( obj instanceof String ) // OK
.....
else if( obj instanceof (String []) ) // Syntax
.... // error
else throw new IllegalArgumentException();
---------------------------------------------
What's wrong here ?
I understand that exists some workaround like
if( obj.getClass() == .... )
But it don't seem elegant enough.

Thank you.

[Igor Ko]

It seems a little strange syntax here, because
String str = (String) obj;
String [] str = (String [])obj;
Works well.
----------------------------------------------
if( obj instanceof String )
... // OK
if( obj instanceof (String [] ) // Wrong syntax
...
Is Java compiler a little strange ???

[Ilja Preuss]

What compiler error do you get?
BTW, you should think about simply overriding the method:

void function(String[] array) {
....
}
  
void function(String singleString) {
  function(new String[] { singleString });
}

or

void function(String[] array) {
  for (int index = 0; index < array.length(); index++) {
    function(array[index]);
  }
}
  
void function(String singleString) {
  ...
}

[Igor Ko]

And I found my error:
-----------------------------------------------
void function(Object obj){
if( obj instanceof String )
...
else if( obj instanceof (String[]) )
... ^
Syntax error - illegal start of type
-----------------------------------------------
After error fix:
else if( obj instanceof String[] )
it passed compilation.
----------------------------------------------
And you are right about overriding - it's more
simple solution, without any dynamic type checking
Thank you !

[Lance Finney]

Just to clarify, the concept you are suggesting is overloading, not overriding.
Overloading is providing different signatures for the same method name.
Overriding is writing a new method with the same signature and name as one in a superclass.

[Ilja Preuss]

Originally posted by Lance Finney:
Just to clarify, the concept you are suggesting is overloading, not overriding.

Ooops...
Thanks for the correction!

[Igor Ko]

Overloading, not overriding. Thanks.

[Marilyn de Queiroz]

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