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https://issues.apache.org/jira/browse/VELOCITY-23?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Henning Schmiedehausen closed VELOCITY-23.
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> Add handling of primitive arrays with foreach
> ---------------------------------------------
>
> Key: VELOCITY-23
> URL: https://issues.apache.org/jira/browse/VELOCITY-23
> Project: Velocity
> Issue Type: Bug
> Components: Build
> Affects Versions: 1.1
> Environment: Operating System: other
> Platform: Other
> Reporter: Dale King
> Assigned To: Velocity-Dev List
>
> It would be really nice if you added support for primitive arrays with
> foreach.
> You currently handle arrays of objects by creating an iterator for the array
> when invoking foreach on it. Why not do the same thing with primitive arrays.
> I know you will probably tell me that I can always create my own wrapper
> around
> the array, but that has its problems.
> I can create my own Iterator wrapper and add it to the context, but what if I
> need to use that data in multiple foreach statements? I can't use the same
> iterator more than once.
> I could create a Collection wrapper for the array, but that is a lot of extra
> work. I don't need the entire collection interface I just want you to iterate
> over the array.
> I could create another array creating wrappers for each item (e.g. if I have
> a
> byte[] create a Byte[]), but that is horribly inefficient for arrays of any
> size.
> So the best solution is for Velocity to create an iterator on demand.
> It really is not difficult to actually achieve. You already have the
> ArrayIterator class for iterating over arrays of Object. It is easily
> modified
> to work with any array. Or you can create a separate iterator for primitive
> arrays.
> To see how to do that here is the source for the PrimitiveArrayIterator from
> WebMacro which you can compare to your ArrayIterator:
> final public class PrimitiveArrayIterator implements Iterator
> {
> private final Object a;
> private int _size;
> private int pos;
> public PrimitiveArrayIterator(Object array)
> {
> if (!array.getClass().isArray())
> throw new IllegalArgumentException(array.getClass().getName()
> + " is not an array.");
> this.a = array;
> _size = java.lang.reflect.Array.getLength(a);
> pos = 0;
> }
> /**
> * Return true if we have not yet reached the end of the enumeration
> */
> final public boolean hasNext()
> {
> return (pos < _size);
> }
> /**
> * Advance the iterator and return the next value. Return null if we
> * reach the end of the enumeration.
> */
> final public Object next() throws NoSuchElementException
> {
> if (pos < _size) {
> return java.lang.reflect.Array.get(a, pos++);
> } else {
> throw new NoSuchElementException("Advanced beyond end of array");
> }
> }
> final public void remove() throws UnsupportedOperationException
> {
> throw new UnsupportedOperationException();
> }
> }
> If you changed your ArrayIterator to work with any type of array then all you
> have to change is instead of this in ForEach.java:
> if( listObject instanceof Object[] )
> You would have:
> if( listObject.getClass().isArray() )
> And you would not have the cast when creating the ArrayIterator further down.
> By the way, while looking at this I noticed that Context.java has an unused
> import of ArrayIterator.
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