public class FastArrayList
extends java.util.ArrayList
A customized implementation of java.util.ArrayList
designed
to operate in a multithreaded environment where the large majority of
method calls are read-only, instead of structural changes. When operating
in "fast" mode, read calls are non-synchronized and write calls perform the
following steps:
When first created, objects of this class default to "slow" mode, where
all accesses of any type are synchronized but no cloning takes place. This
is appropriate for initially populating the collection, followed by a switch
to "fast" mode (by calling setFast(true)
) after initialization
is complete.
NOTE: If you are creating and accessing an
ArrayList
only within a single thread, you should use
java.util.ArrayList
directly (with no synchronization), for
maximum performance.
NOTE: This class is not cross-platform. Using it may cause unexpected failures on some architectures. It suffers from the same problems as the double-checked locking idiom. In particular, the instruction that clones the internal collection and the instruction that sets the internal reference to the clone can be executed or perceived out-of-order. This means that any read operation might fail unexpectedly, as it may be reading the state of the internal collection before the internal collection is fully formed. For more information on the double-checked locking idiom, see the Double-Checked Locking Idiom Is Broken Declaration.
Constructor and Description |
---|
FastArrayList()
Construct a an empty list.
|
FastArrayList(java.util.Collection collection)
Construct a list containing the elements of the specified collection,
in the order they are returned by the collection's iterator.
|
FastArrayList(int capacity)
Construct an empty list with the specified capacity.
|
Modifier and Type | Method and Description |
---|---|
void |
add(int index,
java.lang.Object element)
Insert the specified element at the specified position in this list,
and shift all remaining elements up one position.
|
boolean |
add(java.lang.Object element)
Appends the specified element to the end of this list.
|
boolean |
addAll(java.util.Collection collection)
Append 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.
|
boolean |
addAll(int index,
java.util.Collection collection)
Insert all of the elements in the specified Collection at the specified
position in this list, and shift any previous elements upwards as
needed.
|
void |
clear()
Remove all of the elements from this list.
|
java.lang.Object |
clone()
Return a shallow copy of this
FastArrayList instance. |
boolean |
contains(java.lang.Object element)
Return
true if this list contains the specified element. |
boolean |
containsAll(java.util.Collection collection)
Return
true if this list contains all of the elements
in the specified Collection. |
void |
ensureCapacity(int capacity)
Increase the capacity of this
ArrayList instance, if
necessary, to ensure that it can hold at least the number of elements
specified by the minimum capacity argument. |
boolean |
equals(java.lang.Object o)
Compare the specified object with this list for equality.
|
java.lang.Object |
get(int index)
Return the element at the specified position in the list.
|
boolean |
getFast()
Returns true if this list is operating in fast mode.
|
int |
hashCode()
Return the hash code value for this list.
|
int |
indexOf(java.lang.Object element)
Search for the first occurrence of the given argument, testing
for equality using the
equals() method, and return
the corresponding index, or -1 if the object is not found. |
boolean |
isEmpty()
Test if this list has no elements.
|
java.util.Iterator |
iterator()
Return an iterator over the elements in this list in proper sequence.
|
int |
lastIndexOf(java.lang.Object element)
Search for the last occurrence of the given argument, testing
for equality using the
equals() method, and return
the corresponding index, or -1 if the object is not found. |
java.util.ListIterator |
listIterator()
Return an iterator of the elements of this list, in proper sequence.
|
java.util.ListIterator |
listIterator(int index)
Return an iterator of the elements of this list, in proper sequence,
starting at the specified position.
|
java.lang.Object |
remove(int index)
Remove the element at the specified position in the list, and shift
any subsequent elements down one position.
|
boolean |
remove(java.lang.Object element)
Remove the first occurrence of the specified element from the list,
and shift any subsequent elements down one position.
|
boolean |
removeAll(java.util.Collection collection)
Remove from this collection all of its elements that are contained
in the specified collection.
|
boolean |
retainAll(java.util.Collection collection)
Remove from this collection all of its elements except those that are
contained in the specified collection.
|
java.lang.Object |
set(int index,
java.lang.Object element)
Replace the element at the specified position in this list with
the specified element.
|
void |
setFast(boolean fast)
Sets whether this list will operate in fast mode.
|
int |
size()
Return the number of elements in this list.
|
java.util.List |
subList(int fromIndex,
int toIndex)
Return a view of the portion of this list between fromIndex
(inclusive) and toIndex (exclusive).
|
java.lang.Object[] |
toArray()
Return an array containing all of the elements in this list in the
correct order.
|
java.lang.Object[] |
toArray(java.lang.Object[] array)
Return an array containing all of the elements in this list in the
correct order.
|
java.lang.String |
toString()
Return a String representation of this object.
|
void |
trimToSize()
Trim the capacity of this
ArrayList instance to be the
list's current size. |
public FastArrayList()
public FastArrayList(int capacity)
capacity
- The initial capacity of the empty listpublic FastArrayList(java.util.Collection collection)
collection
- The collection whose elements initialize the contents
of this listpublic boolean getFast()
public void setFast(boolean fast)
fast
- true if the list should operate in fast modepublic boolean add(java.lang.Object element)
add
in interface java.util.Collection
add
in interface java.util.List
add
in class java.util.ArrayList
element
- The element to be appendedpublic void add(int index, java.lang.Object element)
add
in interface java.util.List
add
in class java.util.ArrayList
index
- Index at which to insert this elementelement
- The element to be insertedjava.lang.IndexOutOfBoundsException
- if the index is out of rangepublic boolean addAll(java.util.Collection collection)
addAll
in interface java.util.Collection
addAll
in interface java.util.List
addAll
in class java.util.ArrayList
collection
- The collection to be appendedpublic boolean addAll(int index, java.util.Collection collection)
addAll
in interface java.util.List
addAll
in class java.util.ArrayList
index
- Index at which insertion takes placecollection
- The collection to be addedjava.lang.IndexOutOfBoundsException
- if the index is out of rangepublic void clear()
clear
in interface java.util.Collection
clear
in interface java.util.List
clear
in class java.util.ArrayList
java.lang.UnsupportedOperationException
- if clear()
is not supported by this listpublic java.lang.Object clone()
FastArrayList
instance.
The elements themselves are not copied.clone
in class java.util.ArrayList
public boolean contains(java.lang.Object element)
true
if this list contains the specified element.contains
in interface java.util.Collection
contains
in interface java.util.List
contains
in class java.util.ArrayList
element
- The element to test forpublic boolean containsAll(java.util.Collection collection)
true
if this list contains all of the elements
in the specified Collection.containsAll
in interface java.util.Collection
containsAll
in interface java.util.List
containsAll
in class java.util.AbstractCollection
collection
- Collection whose elements are to be checkedpublic void ensureCapacity(int capacity)
ArrayList
instance, if
necessary, to ensure that it can hold at least the number of elements
specified by the minimum capacity argument.ensureCapacity
in class java.util.ArrayList
capacity
- The new minimum capacitypublic boolean equals(java.lang.Object o)
List.equals
method.equals
in interface java.util.Collection
equals
in interface java.util.List
equals
in class java.util.AbstractList
o
- Object to be compared to this listpublic java.lang.Object get(int index)
get
in interface java.util.List
get
in class java.util.ArrayList
index
- The index of the element to returnjava.lang.IndexOutOfBoundsException
- if the index is out of rangepublic int hashCode()
List.hashCode
method.hashCode
in interface java.util.Collection
hashCode
in interface java.util.List
hashCode
in class java.util.AbstractList
public int indexOf(java.lang.Object element)
equals()
method, and return
the corresponding index, or -1 if the object is not found.indexOf
in interface java.util.List
indexOf
in class java.util.ArrayList
element
- The element to search forpublic boolean isEmpty()
isEmpty
in interface java.util.Collection
isEmpty
in interface java.util.List
isEmpty
in class java.util.ArrayList
public java.util.Iterator iterator()
Thread safety
The iterator returned is thread-safe ONLY in FAST mode.
In slow mode there is no way to synchronize, or make the iterator thread-safe.
In fast mode iteration and modification may occur in parallel on different threads, however there is a restriction. Modification must be EITHER via the Iterator interface methods OR the List interface. If a mixture of modification methods is used a ConcurrentModificationException is thrown from the iterator modification method. If the List modification methods are used the changes are NOT visible in the iterator (it shows the list contents at the time the iterator was created).
iterator
in interface java.lang.Iterable
iterator
in interface java.util.Collection
iterator
in interface java.util.List
iterator
in class java.util.ArrayList
public int lastIndexOf(java.lang.Object element)
equals()
method, and return
the corresponding index, or -1 if the object is not found.lastIndexOf
in interface java.util.List
lastIndexOf
in class java.util.ArrayList
element
- The element to search forpublic java.util.ListIterator listIterator()
Thread safety
The iterator returned is thread-safe ONLY in FAST mode.
In slow mode there is no way to synchronize, or make the iterator thread-safe.
In fast mode iteration and modification may occur in parallel on different threads, however there is a restriction. Modification must be EITHER via the Iterator interface methods OR the List interface. If a mixture of modification methods is used a ConcurrentModificationException is thrown from the iterator modification method. If the List modification methods are used the changes are NOT visible in the iterator (it shows the list contents at the time the iterator was created).
listIterator
in interface java.util.List
listIterator
in class java.util.ArrayList
public java.util.ListIterator listIterator(int index)
Thread safety
The iterator returned is thread-safe ONLY in FAST mode.
In slow mode there is no way to synchronize, or make the iterator thread-safe.
In fast mode iteration and modification may occur in parallel on different threads, however there is a restriction. Modification must be EITHER via the Iterator interface methods OR the List interface. If a mixture of modification methods is used a ConcurrentModificationException is thrown from the iterator modification method. If the List modification methods are used the changes are NOT visible in the iterator (it shows the list contents at the time the iterator was created).
listIterator
in interface java.util.List
listIterator
in class java.util.ArrayList
index
- The starting position of the iterator to returnjava.lang.IndexOutOfBoundsException
- if the index is out of rangepublic java.lang.Object remove(int index)
remove
in interface java.util.List
remove
in class java.util.ArrayList
index
- Index of the element to be removedjava.lang.IndexOutOfBoundsException
- if the index is out of rangepublic boolean remove(java.lang.Object element)
remove
in interface java.util.Collection
remove
in interface java.util.List
remove
in class java.util.ArrayList
element
- Element to be removedpublic boolean removeAll(java.util.Collection collection)
removeAll
in interface java.util.Collection
removeAll
in interface java.util.List
removeAll
in class java.util.ArrayList
collection
- Collection containing elements to be removedjava.lang.UnsupportedOperationException
- if this optional operation
is not supported by this listpublic boolean retainAll(java.util.Collection collection)
retainAll
in interface java.util.Collection
retainAll
in interface java.util.List
retainAll
in class java.util.ArrayList
collection
- Collection containing elements to be retainedjava.lang.UnsupportedOperationException
- if this optional operation
is not supported by this listpublic java.lang.Object set(int index, java.lang.Object element)
set
in interface java.util.List
set
in class java.util.ArrayList
index
- Index of the element to replaceelement
- The new element to be storedjava.lang.IndexOutOfBoundsException
- if the index is out of rangepublic int size()
size
in interface java.util.Collection
size
in interface java.util.List
size
in class java.util.ArrayList
public java.util.List subList(int fromIndex, int toIndex)
subList
in interface java.util.List
subList
in class java.util.ArrayList
fromIndex
- The starting index of the sublist viewtoIndex
- The index after the end of the sublist viewjava.lang.IndexOutOfBoundsException
- if an index is out of rangepublic java.lang.Object[] toArray()
toArray
in interface java.util.Collection
toArray
in interface java.util.List
toArray
in class java.util.ArrayList
public java.lang.Object[] toArray(java.lang.Object[] array)
toArray
in interface java.util.Collection
toArray
in interface java.util.List
toArray
in class java.util.ArrayList
array
- Array defining the element type of the returned listjava.lang.ArrayStoreException
- if the runtime type of array
is not a supertype of the runtime type of every element in this listpublic java.lang.String toString()
toString
in class java.util.AbstractCollection
public void trimToSize()
ArrayList
instance to be the
list's current size. An application can use this operation to minimize
the storage of an ArrayList
instance.trimToSize
in class java.util.ArrayList
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