Decorates another
List
to make it seamlessly grow when
indices larger than the list size are used on add and set,
avoiding most IndexOutOfBoundsExceptions.
This class avoids errors by growing when a set or add method would
normally throw an IndexOutOfBoundsException.
Note that IndexOutOfBoundsException IS returned for invalid negative indices.
Trying to set or add to an index larger than the size will cause the list
to grow (using
null
elements). Clearly, care must be taken
not to use excessively large indices, as the internal list will grow to
match.
Trying to use any method other than add or set with an invalid index will
call the underlying list and probably result in an IndexOutOfBoundsException.
Take care when using this list with
null
values, as
null
is the value added when growing the list.
All sub-lists will access the underlying list directly, and will throw
IndexOutOfBoundsExceptions.
This class differs from
LazyList
because here growth occurs on
set and add, where
LazyList
grows on get. However, they
can be used together by decorating twice.
add
public void add(int index,
Object element)
Decorate the add method to perform the growth behaviour.
If the requested index is greater than the current size, the list will
grow to the new size. Indices between the old size and the requested
size will be filled with
null
.
If the index is less than the current size, the value will be added to
the underlying list directly.
If the index is less than zero, the underlying list is called, which
will probably throw an IndexOutOfBoundsException.
- add in interface AbstractListDecorator
index
- the index to add atelement
- the object to add at the specified index
addAll
public boolean addAll(int index,
Collection coll)
Decorate the addAll method to perform the growth behaviour.
If the requested index is greater than the current size, the list will
grow to the new size. Indices between the old size and the requested
size will be filled with
null
.
If the index is less than the current size, the values will be added to
the underlying list directly.
If the index is less than zero, the underlying list is called, which
will probably throw an IndexOutOfBoundsException.
- addAll in interface AbstractListDecorator
index
- the index to add atcoll
- the collection to add at the specified index
decorate
public static List decorate(List list)
Factory method to create a growth list.
list
- the list to decorate, must not be null
set
public Object set(int index,
Object element)
Decorate the set method to perform the growth behaviour.
If the requested index is greater than the current size, the list will
grow to the new size. Indices between the old size and the requested
size will be filled with
null
.
If the index is less than the current size, the value will be set onto
the underlying list directly.
If the index is less than zero, the underlying list is called, which
will probably throw an IndexOutOfBoundsException.
- set in interface AbstractListDecorator
index
- the index to setelement
- the object to set at the specified index
- the object previously at that index