Re: [JGIT PATCH 1/6] Add set to IntList

[Robin Rosenberg <robin.rosenberg.lists@dewire.com>]

lördag 02 maj 2009 04:08:42 skrev "Shawn O. Pearce" <spearce@spearce.org>:
> Some applications may wish to modify an int list.
> 
> Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
> ---
>  .../tst/org/spearce/jgit/util/IntListTest.java     |   21 ++++++++++++++++++++
>  .../src/org/spearce/jgit/util/IntList.java         |   17 ++++++++++++++++
>  2 files changed, 38 insertions(+), 0 deletions(-)
> 
> diff --git a/org.spearce.jgit.test/tst/org/spearce/jgit/util/IntListTest.java b/org.spearce.jgit.test/tst/org/spearce/jgit/util/IntListTest.java
> index c470d55..ce0d7af 100644
> --- a/org.spearce.jgit.test/tst/org/spearce/jgit/util/IntListTest.java
> +++ b/org.spearce.jgit.test/tst/org/spearce/jgit/util/IntListTest.java
> @@ -144,6 +144,27 @@ public void testClear() {
>  		}
>  	}
>  
> +	public void testSet() {
> +		final IntList i = new IntList();
> +		i.add(1);
> +		assertEquals(1, i.size());
> +		assertEquals(1, i.get(0));
> +		
> +		i.set(0, 5);
> +		assertEquals(5, i.get(0));
> +		
> +		try {
> +			i.set(5, 5);
> +			fail("accepted set of 5 beyond end of list");
> +		} catch (ArrayIndexOutOfBoundsException e){
> +			assertTrue(true);
> +		}
> +
> +		i.set(1, 2);
Oh, you grow the array here. Not obvious.

> +		assertEquals(2, i.size());
> +		assertEquals(2, i.get(1));
> +	}
> +
>  	public void testToString() {
>  		final IntList i = new IntList();
>  		i.add(1);
> diff --git a/org.spearce.jgit/src/org/spearce/jgit/util/IntList.java b/org.spearce.jgit/src/org/spearce/jgit/util/IntList.java
> index 0a84793..9d86a5c 100644
> --- a/org.spearce.jgit/src/org/spearce/jgit/util/IntList.java
> +++ b/org.spearce.jgit/src/org/spearce/jgit/util/IntList.java
> @@ -94,6 +94,23 @@ public void add(final int n) {
>  	}
>  
>  	/**
> +	 * Assign an entry in the list.
> +	 * 
> +	 * @param index
> +	 *            index to set, must be in the range [0, {@link #size()}).
> +	 * @param n
> +	 *            value to store at the position.
> +	 */
> +	public void set(final int index, final int n) {
> +		if (count < index)
> +			throw new ArrayIndexOutOfBoundsException(index);
> +		else if (count == index)
> +			add(n);

The interface is quite obscure here. One the one hand it checks for assignment
outside the set but it does grow the array when only one entry is missing. The
reader of the code won't see that easily. A different name and reflection of the
behaviour in the javadoc is needed. The class javadoc says "A more efficient 
List<Integer> using a primitive integer array." and I know of no java.util.List's 
that expand implicitly.

-- robin