List wrapper class that allows for elements to be
automatically populated as they are requested. This is particularly
useful for data binding to Lists, allowing for elements
to be created and added to the List in a "just in time" fashion.Note
This class is not thread-safe. To create a thread-safe version,
use the java. utility methods.
Inspired by LazyList from Commons Collections.
| Modifier and Type | Class and Description |
|---|---|
| public static interface | AutoPopulatingList.ElementFactory<
the element type E>Factory interface for creating elements for an index-based access
data structure such as a |
| public static class | AutoPopulatingList.ElementInstantiationException
Exception to be thrown from ElementFactory. |
| private static class | AutoPopulatingList.ReflectiveElementFactory<E>
Reflective implementation of the ElementFactory interface, using
|
| Modifier and Type | Field and Description |
|---|---|
| private final List | backingList
The |
| private final AutoPopulatingList. | elementFactory
The |
| Access | Constructor and Description |
|---|---|
| public | AutoPopulatingList(Class<? extends E> elementClass)
Creates a new |
| public | AutoPopulatingList(List<E> backingList, Class<? extends E> elementClass)
Creates a new |
| public | AutoPopulatingList(AutoPopulatingList.
Creates a new |
| public | AutoPopulatingList(List<E> backingList, AutoPopulatingList.
Creates a new |
| Modifier and Type | Method and Description |
|---|---|
| public void | add(int
index at which the specified element is to be inserted index, E element to be inserted element)Implements java. |
| public boolean | add(E
element to be appended to this list o)Implements java. |
| public boolean | addAll(Collection<? extends E>
collection containing elements to be added to this list c)Implements java. |
| public boolean | addAll(int
index at which to insert the first element from the
specified collection index, Collection<? extends E> collection containing elements to be added to this list c)Implements java. |
| public void | clear()
Implements java. |
| public boolean | contains(Object
element whose presence in this list is to be tested o)Implements java. true if this list contains the specified element.
|
| public boolean | containsAll(Collection<?>
collection to be checked for containment in this list c)Implements java. true if this list contains all of the elements of the
specified collection.
|
| public boolean | equals(Object
the object to be compared for equality with this list other)Overrides java. Implements java. |
| public E | get(int
index of the element to return index)Implements java. |
| public int | hashCode()
Overrides java. Implements java. |
| public int | indexOf(Object
element to search for o)Implements java. |
| public boolean | |
| public Iterator | iterator()
Implements java. |
| public int | lastIndexOf(Object
element to search for o)Implements java. |
| public ListIterator | listIterator()
Implements java. |
| public ListIterator | listIterator(int
index of the first element to be returned from the
list iterator (by a call to index)next)Implements java. |
| public E | remove(int
the index of the element to be removed index)Implements java. |
| public boolean | remove(Object
element to be removed from this list, if present o)Implements java. |
| public boolean | removeAll(Collection<?>
collection containing elements to be removed from this list c)Implements java. |
| public boolean | retainAll(Collection<?>
collection containing elements to be retained in this list c)Implements java. |
| public E | set(int
index of the element to replace index, E element to be stored at the specified position element)Implements java. |
| public int | |
| public List | subList(int
low endpoint (inclusive) of the subList fromIndex, int high endpoint (exclusive) of the subList toIndex)Implements java. fromIndex, inclusive, and toIndex, exclusive.
|
| public Object[] | toArray()
Implements java. |
| public <T> T[] | toArray(T[]
the array into which the elements of this list are to
be stored, if it is big enough; otherwise, a new array of the
same runtime type is allocated for this purpose. a)Implements java. |
| backingList | back to summary |
|---|---|
| private final List<E> backingList The | |
| elementFactory | back to summary |
|---|---|
| private final AutoPopulatingList. The | |
| AutoPopulatingList | back to summary |
|---|---|
| public AutoPopulatingList(Class<? extends E> elementClass) Creates a new | |
| AutoPopulatingList | back to summary |
|---|---|
| public AutoPopulatingList(List<E> backingList, Class<? extends E> elementClass) Creates a new | |
| AutoPopulatingList | back to summary |
|---|---|
| public AutoPopulatingList(AutoPopulatingList. Creates a new | |
| AutoPopulatingList | back to summary |
|---|---|
| public AutoPopulatingList(List<E> backingList, AutoPopulatingList. Creates a new | |
| add | back to summary |
|---|---|
| public void add(int index, E element) Implements java. Doc from java. Inserts the specified element at the specified position in this list (optional operation). Shifts the element currently at that position (if any) and any subsequent elements to the right (adds one to their indices).
| |
| add | back to summary |
|---|---|
| public boolean add(E o) Implements java. Doc from java. Appends the specified element to the end of this list (optional operation). Lists that support this operation may place limitations on what elements may be added to this list. In particular, some lists will refuse to add null elements, and others will impose restrictions on the type of elements that may be added. List classes should clearly specify in their documentation any restrictions on what elements may be added.
| |
| addAll | back to summary |
|---|---|
| public boolean addAll(Collection<? extends E> c) Implements java. Doc from java. Appends all of the elements in the specified collection to the end of this list, in the order that they are returned by the specified collection's iterator (optional operation). The behavior of this operation is undefined if the specified collection is modified while the operation is in progress. (Note that this will occur if the specified collection is this list, and it's nonempty.)
| |
| addAll | back to summary |
|---|---|
| public boolean addAll(int index, Collection<? extends E> c) Implements java. Doc from java. Inserts all of the elements in the specified collection into this list at the specified position (optional operation). Shifts the element currently at that position (if any) and any subsequent elements to the right (increases their indices). The new elements will appear in this list in the order that they are returned by the specified collection's iterator. The behavior of this operation is undefined if the specified collection is modified while the operation is in progress. (Note that this will occur if the specified collection is this list, and it's nonempty.)
| |
| clear | back to summary |
|---|---|
| public void clear() Implements java. Doc from java. Removes all of the elements from this list (optional operation). The list will be empty after this call returns.
| |
| contains | back to summary |
|---|---|
| public boolean contains(Object o) Implements java. Doc from java. Returns | |
| containsAll | back to summary |
|---|---|
| public boolean containsAll(Collection<?> c) Implements java. Doc from java. Returns
| |
| equals | back to summary |
|---|---|
| public boolean equals(Object other) Overrides java. Implements java. Doc from java. Compares the specified object with this list for equality. Returns
| |
| get | back to summary |
|---|---|
| public E get(int index) Implements java. Get the element at the supplied index, creating it if there is no element at that index.
| |
| hashCode | back to summary |
|---|---|
| public int hashCode() Overrides java. Implements java. Doc from java. Returns the hash code value for this list. The hash code of a list is defined to be the result of the following calculation:
This ensures that list1.equals(list2) implies that
list1.hashCode()==list2.hashCode() for any two lists,
list1 and list2, as required by the general
contract of Object#hashCode.
| |
| indexOf | back to summary |
|---|---|
| public int indexOf(Object o) Implements java. Doc from java. Returns the index of the first occurrence of the specified element
in this list, or -1 if this list does not contain the element.
More formally, returns the lowest index | |
| isEmpty | back to summary |
|---|---|
| public boolean isEmpty() Implements java. Doc from java. Returns
| |
| iterator | back to summary |
|---|---|
| public Iterator Implements java. Doc from java. Returns an iterator over the elements in this list in proper sequence. | |
| lastIndexOf | back to summary |
|---|---|
| public int lastIndexOf(Object o) Implements java. Doc from java. Returns the index of the last occurrence of the specified element
in this list, or -1 if this list does not contain the element.
More formally, returns the highest index | |
| listIterator | back to summary |
|---|---|
| public ListIterator Implements java. Doc from java. Returns a list iterator over the elements in this list (in proper sequence).
| |
| listIterator | back to summary |
|---|---|
| public ListIterator Implements java. Doc from java. Returns a list iterator over the elements in this list (in proper
sequence), starting at the specified position in the list.
The specified index indicates the first element that would be
returned by an initial call to
| |
| remove | back to summary |
|---|---|
| public E remove(int index) Implements java. Doc from java. Removes the element at the specified position in this list (optional operation). Shifts any subsequent elements to the left (subtracts one from their indices). Returns the element that was removed from the list.
| |
| remove | back to summary |
|---|---|
| public boolean remove(Object o) Implements java. Doc from java. Removes the first occurrence of the specified element from this list,
if it is present (optional operation). If this list does not contain
the element, it is unchanged. More formally, removes the element with
the lowest index | |
| removeAll | back to summary |
|---|---|
| public boolean removeAll(Collection<?> c) Implements java. Doc from java. Removes from this list all of its elements that are contained in the specified collection (optional operation).
| |
| retainAll | back to summary |
|---|---|
| public boolean retainAll(Collection<?> c) Implements java. Doc from java. Retains only the elements in this list that are contained in the specified collection (optional operation). In other words, removes from this list all of its elements that are not contained in the specified collection.
| |
| set | back to summary |
|---|---|
| public E set(int index, E element) Implements java. Doc from java. Replaces the element at the specified position in this list with the specified element (optional operation).
| |
| size | back to summary |
|---|---|
| public int size() Implements java. Doc from java. Returns the number of elements in this list. If this list contains
more than
| |
| subList | back to summary |
|---|---|
| public List Implements java. Doc from java. Returns a view of the portion of this list between the specified
This method eliminates the need for explicit range operations (of the sort that commonly exist for arrays). Any operation that expects a list can be used as a range operation by passing a subList view instead of a whole list. For example, the following idiom removes a range of elements from a list:
Similar idioms may be constructed for indexOf and
lastIndexOf, and all of the algorithms in the
Collections class can be applied to a subList.The semantics of the list returned by this method become undefined if the backing list (i.e., this list) is structurally modified in any way other than via the returned list. (Structural modifications are those that change the size of this list, or otherwise perturb it in such a fashion that iterations in progress may yield incorrect results.) | |
| toArray | back to summary |
|---|---|
| public Object[] toArray() Implements java. Doc from java. Returns an array containing all of the elements in this list in proper sequence (from first to last element). The returned array will be "safe" in that no references to it are maintained by this list. (In other words, this method must allocate a new array even if this list is backed by an array). The caller is thus free to modify the returned array. This method acts as bridge between array-based and collection-based APIs. | |
| toArray | back to summary |
|---|---|
| public <T> T[] toArray(T[] a) Implements java. Doc from java. Returns an array containing all of the elements in this list in proper sequence (from first to last element); the runtime type of the returned array is that of the specified array. If the list fits in the specified array, it is returned therein. Otherwise, a new array is allocated with the runtime type of the specified array and the size of this list. If the list fits in the specified array with room to spare (i.e.,
the array has more elements than the list), the element in the array
immediately following the end of the list is set to Like the Suppose
Note that toArray(new Object[0]) is identical in function to
toArray().
| |
java.util.List .
| Modifier and Type | Method and Description |
|---|---|
| public E |
| createElement | back to summary |
|---|---|
| public E createElement(int index) throws ElementInstantiationException Create the element for the supplied index.
| |
| Access | Constructor and Description |
|---|---|
| public | |
| public |
| ElementInstantiationException | back to summary |
|---|---|
| public ElementInstantiationException(String msg) | |
| ElementInstantiationException | back to summary |
|---|---|
| public ElementInstantiationException(String message, Throwable cause) | |
Class.getDeclaredConstructor().newInstance() on a given element class.
| Modifier and Type | Field and Description |
|---|---|
| private final Class |
| Access | Constructor and Description |
|---|---|
| public |
| Modifier and Type | Method and Description |
|---|---|
| public E | createElement(int index)
Implements org. |
| elementClass | back to summary |
|---|---|
| private final Class<? extends E> elementClass | |
| ReflectiveElementFactory | back to summary |
|---|---|
| public ReflectiveElementFactory(Class<? extends E> elementClass) | |
| createElement | back to summary |
|---|---|
| public E createElement(int index) Implements org. Doc from org. Create the element for the supplied index.
| |