How to call method with Object... as parameter

Question

I wonder how can I call a class method which are expecting Object...(Object[]) as parameter.

I can't know at compilation time now many parameters I need to pass to it, so I can't do like somemethod(1,2,3,4,5).

I'm doing big construction like:

if (param.lengts()==5) {
somemethod(1,2,3,4,5);
} elseif (param.lengts()==4) 
somemethod(1,2,3,4);
....

I was trying to pass List<> and ArrayList<> but without success. Is there a simple way how to convert my dynamic array to the method? I can't change method constructor.

Problem about to call the method, not with declare or read parameters inside the method.

what is a "method constructor"? --- The easiest way would probably to overload the method with all eight primitives: someMethod(boolean...), someMethod(byte...), ... ,someMethod(double....), someMethod(Object...). — Turing85
– Turing85, Commented Jun 1, 2018 at 14:36
He probably means that he can't change the method definition. — Bhesh Gurung
– Bhesh Gurung, Commented Jun 1, 2018 at 14:39
somemethod deslare as : public PrinterDocument(IPrintable... printables) { // } — Andrew
– Andrew, Commented Jun 1, 2018 at 14:39
You are dealing with a constructor, not a method. You need to pass instances of IPrintable instead of integers when calling that constructor. — Bhesh Gurung
– Bhesh Gurung, Commented Jun 1, 2018 at 14:40

GBlodgett · Accepted Answer · 2018-06-03 17:54:29Z

1

You can use variable arguments for this:

private void somemethod(Integer.. array) {
}

And call it like this:

somemethod()    
somemethod(1)    
somemethod(1,2)

If you have an arraylist as an input, you can pass it as this:

someMethod(list.toArray(new Integer[list.size()]);

edited Jun 3, 2018 at 17:54

GBlodgett

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answered Jun 1, 2018 at 14:39

qrius

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4 Comments

Andrew Over a year ago

This was not about this. Lets say i have input=ArrayList<integer> as input and i need to call like: somemethod(input[0],input[1],input[2]...input[input.length()-1])

Jonathan Rosenne Over a year ago

Convert the list to an array using the toArray method of the list.

qrius Over a year ago

Andrew check my updated answer, as suggested by @Jonathan as well

Andrew Over a year ago

I guest this is the one i was looking for. Thanks.

David Zimmerman · Accepted Answer · 2018-06-01 15:01:45Z

1

Pass an array.

Object[] params = ... build the array from the args 
somemethod(params);
...
void somemethod(Object... objs);

answered Jun 1, 2018 at 15:01

David Zimmerman

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Comments

Allan Braga · Accepted Answer · 2018-06-01 14:37:20Z

0

You can use var args:

method declaration:

void somemethod(Object ...){ }

And call this methodo with how many parameters you need.

answered Jun 1, 2018 at 14:37

Allan Braga

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