problem with addBefore() in x10.util.ArrayList<T>

[Vincent Liao]

Hi,

My group has been having problems using addBefore(Int i, T v) in x10.util.ArrayList<T> (http://dist.codehaus.org/x10/xdoc/2.1.0/x10/util/ArrayList.html). We want to add a new entry to index 0 of the list, shifting all existing elements up one index. However, using addBefore(0, newElement) seems to shift the elements but then set all the elements to the old index 0. Perhaps the element shifting in the code is incorrect? i.e. the following is being done:

a[1] = a[0];

a[2] = a[1];

...

I've provided a sample snippet of code and the output below.

For now, we're going to make our own addBefore method. Please advise if there is an easier way to fix this. Thanks!

-Vincent

Code:

cl: Rail[ArrayList[CharEntry]]

id: Int

index: Int

temp: CharEntry

...

public class CharEntry {

public val char:Char;

public val i:Int;

public val j:Int;

public def this(char:Char, i:Int, j:Int) {

this.char = char;

this.i = i;

this.j = j;

}

}

...

if (index < cl(id).size()) {

Console.OUT.println("index = " + index);

Console.OUT.println("temp.char = " + temp.char);

Console.OUT.println("BEFORE");

for (e in cl(id)) {

Console.OUT.print(e.char);

}

Console.OUT.println();

atomic cl(id).addBefore(index, temp);

Console.OUT.println("AFTER");

for (e in cl(id)) {

Console.OUT.print(e.char);

}

Console.OUT.println();

}

Output:

index = 0

temp.char = q

BEFORE

qqqqqnrrrrrrrrrrrrrrrrrr

sssssssssssssssssss

tttttttttttttttttttt

uuuuuuuuuuuuuuuuuuuuu

vvvvvvvvvvvvvvvvvvvvvv

wwwwwwwwwwwwwwwwwwwwwww

xxxxxxxxxxxxxxxxxxxxxxxx

yyyyyyyyyyyyyyyyyyyyyyyyy

zzzzzzzzzzzzzzzzzzzzzzzzzz

AFTER

qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqq