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How do I build an array of objects with a Java 5 for loop?

Posted on 2006-07-18
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Last Modified: 2010-03-31
How do I build an array of objects with a Java 5 for loop?

I'd like to populate an array simliar to:

private static final SelectItem[] stateItems = new SelectItem[] {
        new SelectItem("Nebraska"),
        new SelectItem("Texas"),
        new SelectItem("Kansas"),
        new SelectItem("Iowa"),
};

in a loop.

Each SelectItem object value comes from a data source that I can loop through with a Java 5 for statement.

However, what is the proper approach to populate the SelectItem[] stateItems array?

I guess, I get used to using ArrayList, which has an add() method.

Any suggestions or examples are appreciated.

Thank you,

--Todd

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Question by:jtp51
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8 Comments
 
LVL 23

Expert Comment

by:Ajay-Singh
ID: 17135813
0
 
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Expert Comment

by:Ajay-Singh
ID: 17135819
List<SelectItem> list = Arrays.asList(stateItems);
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Expert Comment

by:mukundha_expert
ID: 17135968
>> How do I build an array of objects with a Java 5 for loop?

Object[] obj = new Object[5];
for ( int i =  0 ; i <  array.length ; i ++  )
 obj[i] = new Object() ;



>>SelectItem object value comes from a data source that I can loop through with a Java 5 for statement

if you can get the data from the statement, then form a array of that value ( String array)

say, String[] data = { your values} ;

for ( int i = 0 ; i < stateitems.length ; i ++ )
   stateitems [ i]  = new SelectItem ( data[i] ) ;


if you are using arrayList then,

ArrayList stateitems = new ArrayList () ;
for ( int i = 0 ; i < data.length ; i ++  )

stateitems.add ( new SelectItem ( data [ i ] ) ) ;

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Expert Comment

by:mukundha_expert
ID: 17135974
>>private static final SelectItem[]

if the array is final then you cannot change its reference later, it should be initialzed once it is declared,
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Expert Comment

by:ksivananth
ID: 17135983
SelectItem[] stateItems = new SelectedItem[ 5 ] ;

for( int i = 0; i < 5; i++ ) stateItems[i] = new SelectedItem() ;

Not sure if this is what u wnated ;)
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Expert Comment

by:Mayank S
ID: 17136085
They are not Java 5 for loops. But anyway, why would you want to use the enhanced for loop? I personally don't prefer it as it doesn't give as good performance as the simple for loop.
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LVL 86

Expert Comment

by:CEHJ
ID: 17136804
Using new for loop would be something like

int ix = 0;
for (SelectItem si : dataSource) {
    stateItems[ix++] = si;
}
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Accepted Solution

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Mayank S earned 50 total points
ID: 17138055
If you have them in an array-list/ collection, you can also directly use the toArray () method to get the values in an array.
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