Class GapList<E>

java.lang.Object

java.util.AbstractCollection<E>

java.util.AbstractList<E>

org.magicwerk.brownies.collections.IList<E>

org.magicwerk.brownies.collections.GapList<E>

Type Parameters:

E - type of elements stored in the list

All Implemented Interfaces:

Serializable, Cloneable, Iterable<E>, Collection<E>, List<E>, RandomAccess, SequencedCollection<E>, ICollection<E>, IListable<E>

Direct Known Subclasses:

GapList.ReadOnlyList

public class GapList<E>
extends IList<E>

Class {link GapList} combines the strengths of both ArrayList and LinkedList. It is implemented to offer both efficient random access to elements by index (as ArrayList does) and at the same time efficient adding and removing elements to and from beginning and end (as LinkedList does). It also exploits the locality of reference often seen in applications to further improve performance, e.g. for iterating over the list.

The class can be used as drop-in replacement for ArrayList. It is also source compatible to LinkedList/Deque as it implements all needed methods. It cannot implement Deque however, use IList.asDeque() to get a view implementing it.

Note that this implementation is not synchronized.

Note that the iterators provided are not fail-fast.

Author:

Thomas Mauch

See Also:

• List
• ArrayList
• Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected static class	GapList.ReadOnlyList<E>	A read-only version of GapList.

Nested classes/interfaces inherited from class IList

IList.IListableFromArray<E>, IList.IListableFromCollection<E>, IList.IListableFromList<E>, IList.IListableFromMult<E>

Field Summary

Fields

Modifier and Type	Field	Description
static final int	DEFAULT_CAPACITY	Default capacity for list

Fields inherited from class AbstractList

modCount

Constructor Summary

Constructors

Modifier	Constructor	Description
	GapList()	Construct a list with the default initial capacity.
protected	GapList(boolean copy, GapList<E> that)	Constructor used internally, e.g. for ImmutableGapList.
	GapList(int capacity)	Construct a list with specified initial capacity.
	GapList(Collection<? extends E> coll)	Construct a list to contain the specified elements.

Method Summary

Modifier and Type	Method	Description
void	add(int index, E elem)	Inserts the specified element at the specified position in this list.
boolean	add(E elem)
<K> int	binarySearch(int index, int len, K key, Comparator<? super K> comparator)	Searches the specified range for an object using the binary search algorithm.
int	capacity()	Returns capacity of this list.
GapList<E>	clone()	Returns a shallow copy of this list.
GapList<E>	copy()	Returns a shallow copy of this list.
static <E> GapList<E>	create()	Create new list.
static <E> GapList<E>	create(E... elems)	Create new list with specified elements.
static <E> GapList<E>	create(Collection<? extends E> coll)	Create new list with specified elements.
GapList<E>	crop()	Returns a copy this list but without elements.
protected boolean	doAdd(int index, E elem)	Helper method for adding an element to the list.
protected void	doAssign(IList<E> that)	Assign this list the content of the that list.
protected void	doClear()
protected void	doClone(IList<E> that)	Initialize this object after the bitwise copy has been made by Object.clone().
GapList<E>	doCreate(int capacity)	Create list with specified capacity.
protected void	doEnsureCapacity(int minCapacity)	Increases the capacity of this list instance, if necessary, to ensure that it can hold at least the number of elements specified by the minimum capacity argument.
protected E	doGet(int index)	Helper method for getting an element from the list.
protected <T> void	doGetAll(T[] array, int index, int len)	Helper method to fill the specified elements in an array.
protected E	doRemove(int index)	Helper method to remove an element.
protected void	doRemoveAll(int index, int len)	Remove specified range of elements from list.
protected boolean	doRemoveAllFast(int index, int len)	Remove specified range of elements from list as specialized fast operation.
protected E	doReSet(int index, E elem)	Sets an element at specified position.
protected E	doSet(int index, E elem)	Helper method for setting an element in the list.
static <EE> GapList<EE>	EMPTY()
E	get(int index)	Return element at specified position
GapList<E>	getAll(int index, int len)	Returns specified range of elements from list.
GapList<E>	getAll(E elem)	Returns all elements in the list equal to the specified element.
E	getDefaultElem()
static <E> GapList<E>	immutable(E... elems)	Create new immutable list with specified elements.
static <E> GapList<E>	immutable(Collection<? extends E> coll)	Create new immutable list with specified elements.
GapList<E>	immutableList()	Returns an immutable copy of this list.
boolean	isReadOnly()	Returns true if this list is either unmodifiable or immutable, false otherwise.
<R> GapList<R>	map(Function<E,R> mapper)	Create a new list by applying the specified mapping function to all elements.
E	remove(int index)
int	size()	Return size of list
void	sort(int index, int len, Comparator<? super E> comparator)	Sort specified elements in the list using the specified comparator.
void	trimToSize()	Trims the capacity of this GapList instance to be the list's current size.
GapList<E>	unmodifiableList()	Returns an unmodifiable view of this list.

Methods inherited from class IList

addAll, addAll, addAll, addAll, addArray, addArray, addArray, addArray, addFirst, addIfAbsent, addLast, addMult, addMult, asDeque, asIListable, binarySearch, checkIndex, checkIndexAdd, checkLength, checkLengths, checkNonNull, checkRange, clear, contains, containsAll, containsAny, containsIf, copy, count, countIf, descendingIterator, doAddAll, doCreateArray, doIndexOf, doIndexOfIf, doInitAll, doLastIndexOf, doLastIndexOfIf, doModify, doPutAll, doReplace, doRotate, drag, element, ensureCapacity, equals, extract, extractIf, fill, filter, filterMap, flatMap, getDistinct, getFirst, getFirstOrNull, getIf, getLast, getLastOrNull, getSingle, getSingleOrNull, hashCode, indexOf, indexOf, indexOfIf, indexOfIf, initAll, initAll, initArray, initMult, isEmpty, iterator, lastIndexOf, lastIndexOf, lastIndexOfIf, lastIndexOfIf, listIterator, listIterator, mapFilter, move, offer, offerFirst, offerLast, peek, peekFirst, peekLast, poll, pollFirst, pollLast, pop, push, put, putAll, putAll, putArray, putMult, remove, remove, remove, removeAll, removeAll, removeAll, removeFirst, removeFirstOccurrence, removeIf, removeLast, removeLastOccurrence, replace, replaceAll, replaceAll, replaceArray, replaceMult, resize, retain, retainAll, retainAll, retainIf, reverse, reverse, rotate, rotate, set, setAll, setAll, setArray, setArray, setMult, sort, swap, toArray, toArray, toArray, toArray, toArray, toArray, toString, transferCopy, transferMove, transferRemove, transferSwap, transform, transformedList

Methods inherited from class AbstractList

removeRange, subList

Methods inherited from class Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface Collection

parallelStream, stream, toArray

Methods inherited from interface Iterable

forEach

Methods inherited from interface List

replaceAll, reversed, spliterator, subList

Field Details

DEFAULT_CAPACITY

public static final int DEFAULT_CAPACITY

Default capacity for list

See Also:

• Constant Field Values

Constructor Details

GapList

protected GapList(boolean copy,
 GapList<E> that)

Constructor used internally, e.g. for ImmutableGapList.

Parameters:

copy - true to copy all instance values from source, if false nothing is done

that - list to copy

GapList

public GapList()

Construct a list with the default initial capacity.

GapList

public GapList(int capacity)

Construct a list with specified initial capacity.

Parameters:

capacity - capacity

GapList

public GapList(Collection<? extends E> coll)

Construct a list to contain the specified elements. The list will have an initial capacity to hold these elements.

Parameters:

coll - collection with elements

Method Details

EMPTY

public static <EE> GapList<EE> EMPTY()

Returns:

unmodifiable empty instance

create

public static <E> GapList<E> create()

Create new list.

Type Parameters:

E - type of elements stored in the list

Returns:

created list

create

public static <E> GapList<E> create(Collection<? extends E> coll)

Create new list with specified elements.

Type Parameters:

E - type of elements stored in the list

Parameters:

coll - collection with elements

Returns:

created list

create

@SafeVarargs
public static <E> GapList<E> create(E... elems)

Create new list with specified elements.

Type Parameters:

E - type of elements stored in the list

Parameters:

elems - array with elements

Returns:

created list

immutable

public static <E> GapList<E> immutable(Collection<? extends E> coll)

Create new immutable list with specified elements. To reduce the needed memory, the list's capacity will be equal to its size.

Type Parameters:

E - type of elements stored in the list

Parameters:

coll - collection with elements

Returns:

created list

immutable

@SafeVarargs
public static <E> GapList<E> immutable(E... elems)

Create new immutable list with specified elements. To reduce the needed memory, the list's capacity will be equal to its size.

Type Parameters:

E - type of elements stored in the list

Parameters:

elems - array with elements

Returns:

created list

doAssign

protected void doAssign(IList<E> that)

Description copied from class: IList

Assign this list the content of the that list. This is done by bitwise copying so the that list should not be used afterwards.

Specified by:

doAssign in class IList<E>

Parameters:

that - list to copy content from

getDefaultElem

public E getDefaultElem()

Specified by:

getDefaultElem in class IList<E>

crop

public GapList<E> crop()

Description copied from class: IList

Returns a copy this list but without elements. The new list will have the same type as this list.

Specified by:

crop in interface ICollection<E>

Overrides:

crop in class IList<E>

Returns:

an empty copy of this list

copy

public GapList<E> copy()

Description copied from class: IList

Returns a shallow copy of this list. The new list will contain the same elements as the source list, i.e. the elements themselves are not copied. The capacity of the list will be set to the number of elements, i.e. size and capacity are equal. This returned list will be modifiable, i.e. a read-only list will be copied and be modifiable again.

Specified by:

copy in interface ICollection<E>

Specified by:

copy in class IList<E>

Returns:

a modifiable copy of this list

clone

public GapList<E> clone()

Description copied from class: IList

Returns a shallow copy of this list. The new list will contain the same elements as the source list, i.e. the elements themselves are not copied. The capacity of the list will be set to the number of elements, i.e. size and capacity are equal. If the list is read-only, the same list is returned without change. Use IList.copy() to .

Overrides:

clone in class IList<E>

Returns:

a modifiable copy of this list

isReadOnly

public boolean isReadOnly()

Description copied from class: IList

Returns true if this list is either unmodifiable or immutable, false otherwise.

Specified by:

isReadOnly in class IList<E>

unmodifiableList

public GapList<E> unmodifiableList()

Description copied from class: IList

Returns an unmodifiable view of this list. This method allows modules to provide users with "read-only" access to internal lists, where changes made to the original list are visible as query operations on the returned list "read through" to the specified list. Attempts to modify the returned list, whether direct or via its iterator, result in an UnsupportedOperationException. If this list is already unmodifiable, it is returned unchanged. See IList.immutableList() to get an immutable copy of a list.

Specified by:

unmodifiableList in class IList<E>

Returns:

an unmodifiable view of the specified list

immutableList

public GapList<E> immutableList()

Description copied from class: IList

Returns an immutable copy of this list. The returned list is independent from the original list, i.e. changes done later are not seen. Attempts to modify the returned list, whether direct or via its iterator, result in an UnsupportedOperationException. If this list is already immutable, it is returned unchanged. See IList.unmodifiableList() to get unmodifiable view of a list.

Specified by:

immutableList in class IList<E>

Returns:

an immutable copy of the specified list

doClone

protected void doClone(IList<E> that)

Description copied from class: IList

Initialize this object after the bitwise copy has been made by Object.clone().

Specified by:

doClone in class IList<E>

Parameters:

that - source object

doClear

protected void doClear()

Overrides:

doClear in class IList<E>

size

public int size()

Description copied from interface: IListable

Return size of list

Specified by:

size in interface Collection<E>

Specified by:

size in interface IListable<E>

Specified by:

size in interface List<E>

Specified by:

size in class IList<E>

capacity

public int capacity()

Description copied from class: IList

Returns capacity of this list. Note that two lists are considered equal even if they have a distinct capacity. Also the capacity can be changed by operations like clone() etc.

Specified by:

capacity in class IList<E>

Returns:

capacity of this list

get

public E get(int index)

Description copied from interface: IListable

Return element at specified position

Specified by:

get in interface IListable<E>

Specified by:

get in interface List<E>

Overrides:

get in class IList<E>

doGet

protected E doGet(int index)

Description copied from class: IList

Helper method for getting an element from the list. This is the only method which really gets an element. Override if you need to validity checks before getting.

Specified by:

doGet in class IList<E>

Parameters:

index - index of element to return

Returns:

the element at the specified position in this list

doSet

protected E doSet(int index,
 E elem)

Description copied from class: IList

Helper method for setting an element in the list. This is the only method which really sets an element. Override if you need to validity checks before setting.

Specified by:

doSet in class IList<E>

Parameters:

index - index where element will be placed

elem - element to set

Returns:

old element which was at the position

doReSet

protected E doReSet(int index,
 E elem)

Description copied from class: IList

Sets an element at specified position. This method is used internally if existing elements will be moved etc. Override if you need to validity checks.

Specified by:

doReSet in class IList<E>

Parameters:

index - index where element will be placed

elem - element to set

Returns:

old element which was at the position

add

public boolean add(E elem)

Specified by:

add in interface Collection<E>

Specified by:

add in interface List<E>

Overrides:

add in class IList<E>

add

public void add(int index,
 E elem)

Description copied from class: IList

Inserts the specified element at the specified position in this list. Shifts the element currently at that position (if any) and any subsequent elements to the right (adds one to their indices).

Specified by:

add in interface List<E>

Overrides:

add in class IList<E>

Parameters:

index - index at which the specified element is to be inserted

elem - element to be inserted

getAll

public GapList<E> getAll(int index,
 int len)

Description copied from class: IList

Returns specified range of elements from list.

Overrides:

getAll in class IList<E>

Parameters:

index - index of first element to retrieve

len - number of elements to retrieve

Returns:

list containing the specified range of elements

getAll

public GapList<E> getAll(E elem)

Description copied from class: IList

Returns all elements in the list equal to the specified element.

Overrides:

getAll in class IList<E>

Parameters:

elem - element to look for

Returns:

all elements in the list equal to the specified element

map

public <R> GapList<R> map(Function<E,R> mapper)

Description copied from interface: ICollection

Create a new list by applying the specified mapping function to all elements. The returned list is of type IList, typically GapList unless the original type is BigList.

Specified by:

map in interface ICollection<E>

Overrides:

map in class IList<E>

Parameters:

mapper - mapping function

Returns:

created list

doAdd

protected boolean doAdd(int index,
 E elem)

Description copied from class: IList

Helper method for adding an element to the list. This is the only method which really adds an element. Override if you need to validity checks before adding.

Specified by:

doAdd in class IList<E>

Parameters:

index - index where element should be added (-1 means it is up to the implementation to choose the index)

elem - element to add

Returns:

true if element has been added, false otherwise

remove

public E remove(int index)

Specified by:

remove in interface List<E>

Overrides:

remove in class IList<E>

doRemove

protected E doRemove(int index)

Description copied from class: IList

Helper method to remove an element. This is the only method which really removes an element. Override if you need to validity checks before removing.

Specified by:

doRemove in class IList<E>

Parameters:

index - index of element to remove

Returns:

removed element

doEnsureCapacity

protected void doEnsureCapacity(int minCapacity)

Description copied from class: IList

Increases the capacity of this list instance, if necessary, to ensure that it can hold at least the number of elements specified by the minimum capacity argument.

Specified by:

doEnsureCapacity in class IList<E>

Parameters:

minCapacity - the desired minimum capacity

trimToSize

public void trimToSize()

Trims the capacity of this GapList instance to be the list's current size. An application can use this operation to minimize the storage of an instance.

Specified by:

trimToSize in class IList<E>

doGetAll

protected <T> void doGetAll(T[] array,
 int index,
 int len)

Description copied from class: IList

Helper method to fill the specified elements in an array.

Overrides:

doGetAll in class IList<E>

Type Parameters:

T - type of elements stored in the list

Parameters:

array - array to store the list elements

index - index of first element to copy

len - number of elements to copy

doCreate

public GapList<E> doCreate(int capacity)

Description copied from class: IList

Create list with specified capacity.

Specified by:

doCreate in class IList<E>

Parameters:

capacity - initial capacity (use -1 for default capacity)

Returns:

created list

doRemoveAll

protected void doRemoveAll(int index,
 int len)

Description copied from class: IList

Remove specified range of elements from list.

Overrides:

doRemoveAll in class IList<E>

Parameters:

index - index of first element to remove

len - number of elements to remove

doRemoveAllFast

protected boolean doRemoveAllFast(int index,
 int len)

Remove specified range of elements from list as specialized fast operation.

Parameters:

index - index of first element to remove

len - number of elements to remove

Returns:

true if removal could be done, false otherwise

sort

public void sort(int index,
 int len,
 Comparator<? super E> comparator)

Description copied from class: IList

Sort specified elements in the list using the specified comparator.

Specified by:

sort in class IList<E>

Parameters:

index - index of first element to sort

len - number of elements to sort

comparator - comparator to use for sorting (null means the elements natural ordering should be used)

See Also:

• Arrays.sort(int[])

binarySearch

public <K> int binarySearch(int index,
 int len,
 K key,
 Comparator<? super K> comparator)

Description copied from class: IList

Searches the specified range for an object using the binary search algorithm.

Note that the method is defined to work with an arbitrary type <K>. This allows to search directly for a key field in the object without the need to construct an object containing the key:

persons.binarySearch("john", new SearchByName());

class SearchByName implements Comparator<Object> {
 public int compare(Object o1, Object o2) {
   String s1 = (o1 instanceof String) ? (String) o1 : ((Name) o1).getName();
   String s2 = (o2 instanceof String) ? (String) o2 : ((Name) o2).getName();
   return s1.compareTo(s2);
 }
}
/

Specified by:

binarySearch in class IList<E>

Parameters:

index - index of first element to search

len - number of elements to search

key - the value to be searched for

comparator - the comparator by which the list is ordered. A null value indicates that the elements' natural ordering should be used.

Returns:

index of the search key, if it is contained in the array; otherwise, (-(insertion point) - 1). The insertion point is defined as the point at which the key would be inserted into the array: the index of the first element greater than the key, or a.length if all elements in the array are less than the specified key. Note that this guarantees that the return value will be >= 0 if and only if the key is found.

See Also:

• Arrays.binarySearch(long[], long)