/**
* Factory method to create a SetList using the supplied list to retain order.
* <p>
* If the list contains duplicates, these are removed (first indexed one kept).
* A <code>HashSet</code> is used for the set behaviour.
*
* @param list the list to decorate, must not be null
* @throws IllegalArgumentException if list is null
*/
public static SetUniqueList decorate(java.util.List<Object> list)
{
if (list == null)
{
throw new java.lang.IllegalArgumentException("List must not be null");
}
if (list.isEmpty())
{
return new SetUniqueList(list, new java.util.HashSet<Object>());
}
else
{
java.util.List<Object> temp = new java.util.ArrayList<Object>(list);
list.clear();
SetUniqueList sl = new SetUniqueList(list, new java.util.HashSet<Object>());
sl.addAll(temp);
return sl;
}
}
/**
* Transform the collection by applying a Transformer to each element.
* <p>
* If the input collection or transformer is null, there is no change made.
* <p>
* This routine is best for Lists, for which set() is used to do the
* transformations "in place." For other Collections, clear() and addAll()
* are used to replace elements.
* <p>
* If the input collection controls its input, such as a Set, and the
* Transformer creates duplicates (or are otherwise invalid), the
* collection may reduce in size due to calling this method.
*
* @param collection the collection to get the input from, may be null
* @param transformer the transformer to perform, may be null
*/
public static void transform(java.util.Collection<Object> collection, Transformer transformer)
{
if (collection != null && transformer != null)
{
if (collection is java.util.List<Object>)
{
java.util.List<Object> list = (java.util.List<Object>)collection;
for (java.util.ListIterator<Object> it = list.listIterator(); it.hasNext(); )
{
it.set(transformer.transform(it.next()));
}
}
else
{
java.util.Collection<Object> resultCollection = collect(collection, transformer);
collection.clear();
collection.addAll(resultCollection);
}
}
}