Package org.apache.commons.collections4.list

# Class GrowthList<E>

java.lang.Object
org.apache.commons.collections4.collection.AbstractCollectionDecorator<E>
org.apache.commons.collections4.list.AbstractListDecorator<E>
org.apache.commons.collections4.list.AbstractSerializableListDecorator<E>
org.apache.commons.collections4.list.GrowthList<E>

Type Parameters:
  `E` - the type of the elements in the list.

All Implemented Interfaces:
  `Serializable`, `Iterable<E>`, `Collection<E>`, `List<E>`

public class GrowthList<E> extends AbstractSerializableListDecorator<E>
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.

Since:
  3.2
See Also:
  - `LazyList`
  - Serialized Form

- ## Constructor Summary

  Constructors
  Modifier
  Constructor
  Description
  ``
  `GrowthList()`
  Constructor that uses an ArrayList internally.
  ``
  `GrowthList(int initialCapacity)`
  Constructor that uses an ArrayList internally.
  `protected`
  `GrowthList(List<E> list)`
  Constructor that wraps (not copies).

- ## Method Summary

  Modifier and Type
  Method
  Description
  `void`
  `add(int index, E element)`
  Decorate the add method to perform the growth behavior.
  `boolean`
  `addAll(int index, Collection<? extends E> coll)`
  Decorate the addAll method to perform the growth behavior.
  `static <E> GrowthList<E>`
  `growthList(List<E> list)`
  Factory method to create a growth list.
  `E`
  `set(int index, E element)`
  Decorate the set method to perform the growth behavior.

  ### Methods inherited from class org.apache.commons.collections4.list.AbstractListDecorator

  `decorated, equals, get, hashCode, indexOf, lastIndexOf, listIterator, listIterator, remove, subList`

  ### Methods inherited from class org.apache.commons.collections4.collection.AbstractCollectionDecorator

  `add, addAll, clear, contains, containsAll, isEmpty, iterator, remove, removeAll, removeIf, retainAll, setCollection, size, toArray, toArray, toString`

  ### Methods inherited from class java.lang.Object

  `clone, finalize, getClass, notify, notifyAll, wait, wait, wait`

  ### Methods inherited from interface java.util.Collection

  `parallelStream, removeIf, stream`

  ### Methods inherited from interface java.lang.Iterable

  `forEach`

  ### Methods inherited from interface java.util.List

  `add, addAll, clear, contains, containsAll, isEmpty, iterator, remove, removeAll, replaceAll, retainAll, size, sort, spliterator, toArray, toArray`

- ## Constructor Details

  - ### GrowthList

    public GrowthList()
    Constructor that uses an ArrayList internally.

  - ### GrowthList

    public GrowthList(int initialCapacity)
    Constructor that uses an ArrayList internally.
    Parameters:
      `initialCapacity` - the initial capacity of the ArrayList
    Throws:
      `IllegalArgumentException` - if initial capacity is invalid

  - ### GrowthList

    protected GrowthList(List<E> list)
    Constructor that wraps (not copies).
    Parameters:
      `list` - the list to decorate, must not be null
    Throws:
      `NullPointerException` - if list is null

- ## Method Details

  - ### growthList

    public static <E> GrowthList<E> growthList(List<E> list)
    Factory method to create a growth list.
    Type Parameters:
      `E` - the type of the elements in the list
    Parameters:
      `list` - the list to decorate, must not be null
    Returns:
      a new growth list
    Throws:
      `NullPointerException` - if list is null
    Since:
      4.0

  - ### add

    public void add(int index, E element)
    Decorate the add method to perform the growth behavior.

    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.

    Specified by:
      `add` in interface `List<E>`
    Overrides:
      `add` in class `AbstractListDecorator<E>`
    Parameters:
      `index` - the index to add at
      `element` - the object to add at the specified index
    Throws:
      `UnsupportedOperationException` - if the underlying list doesn't implement set
      `ClassCastException` - if the underlying list rejects the element
      `IllegalArgumentException` - if the underlying list rejects the element

  - ### addAll

    public boolean addAll(int index, Collection<? extends E> coll)
    Decorate the addAll method to perform the growth behavior.

    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.

    Specified by:
      `addAll` in interface `List<E>`
    Overrides:
      `addAll` in class `AbstractListDecorator<E>`
    Parameters:
      `index` - the index to add at
      `coll` - the collection to add at the specified index
    Returns:
      true if the list changed
    Throws:
      `UnsupportedOperationException` - if the underlying list doesn't implement set
      `ClassCastException` - if the underlying list rejects the element
      `IllegalArgumentException` - if the underlying list rejects the element

  - ### set

    public E set(int index, E element)
    Decorate the set method to perform the growth behavior.

    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.

    Specified by:
      `set` in interface `List<E>`
    Overrides:
      `set` in class `AbstractListDecorator<E>`
    Parameters:
      `index` - the index to set
      `element` - the object to set at the specified index
    Returns:
      the object previously at that index
    Throws:
      `UnsupportedOperationException` - if the underlying list doesn't implement set
      `ClassCastException` - if the underlying list rejects the element
      `IllegalArgumentException` - if the underlying list rejects the element