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Re: create an ArrayList + add a first element and return the List in ONE statement possible ?

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  Re: create an ArrayList + add a first element and return the List in ONE statement possible ? Lew <noone@lewscanon.com> - 2011-01-27 15:17 -0500

#26203 — Re: create an ArrayList + add a first element and return the List in ONE statement possible ?

Robin Wenger wrote:
>> As the subject said I wonder whether there is really no one-liner for creating an ArrayList + assign of the first element +
>> return the new list. I have expected the following to work in such a way but it does NOT work:
>>
>>    Object77 oneObject = new Object77();
>>    ArrayList<Object77>  lObj = new ArrayList<Object77>(oneObject);
>>
>> The following returns a boolean and not the desired List:
>>
>>    boolean success = (new ArrayListObject77>()).add(oneObject);
>>
>> Any other ideas?
>> Or do I really have to split this simple operation into separate statements?

Why is it a problem to split it into separate statements?

Ian Pilcher wrote:
> There are lots of ways, including:
>
>      ArrayList<Object77>  lObj = new ArrayList<Object77>(
>              Collections.singleton(new Object77()));

The declared type should probably be 'List<Object77>'.

The Javadocs might also lead one to:

  List <Object77> lObj = new ArrayList <Object77>
   ( Arrays.asList( new Object77() ));

or, if you aren't particular about the implementation:

  List <Object77> lObj = Arrays.asList( new Object77() );

which saves a copy operation.

As Ian said, there are many ways.  Know thy API.  The study of the collections 
types is especially rewarding.

http://download.oracle.com/javase/tutorial/collections/index.html

-- 
Lew
Ceci n'est pas une pipe.

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