oracle.jbo.server.java.util
Class ArrayList

java.lang.Object
oracle.jbo.server.java.util.AbstractCollection
oracle.jbo.server.java.util.AbstractList
oracle.jbo.server.java.util.ArrayList

All Implemented Interfaces:

java.lang.Cloneable, Collection, List, java.io.Serializable

public class ArrayList

extends AbstractList

implements List, java.lang.Cloneable, java.io.Serializable

Resizable-array implementation of the List interface. Implements all optional List operations, and permits all elements, including null. In addition to implementing the List interface, ArrayList provides methods to manipulate the size of the array that is used internally to store the List. (Arrayist is roughly equivalent to Vector, except that it is unsynchronized.)

The size, isEmpty, get, set, clear, iterator, and listIterator operations run in constant time. The add() operation runs in constant time unless it causes the ArrayList to exceed its capacity, in which case it runs in linear time. All of the other operations run in linear time (roughly speaking). The constant factor is low compared to that for LinkedList.

Each ArrayList has a capacity and a capacityIncrement. The capacity is the size of the array used to store the elements in the List. It is always at least as large as the List size; it is usually larger because as components are added to the ArrayList, the ArrayList's storage increases in chunks the size of its capacityIncrement. (The capacityIncrement does not change over the lifetime of the ArrayList.) An application can increase the capacity of an ArrayList before inserting a large number of components; this reduces the amount of incremental reallocation.

Note that this implementation is not synchronized. If multiple threads access an ArrayList concurrently, and at least one of the threads modifies the ArrayList structurally, it must be synchronized externally. (A structural modification is any operation that adds or deletes one or more elements, or explicitly resizes the backing array; merely setting the value of an element is not a structural modification.) This is typically accomplished by synchronizing on some object that naturally encapsulates the ArrayList. If no such object exists, the ArrayList should be "wrapped" using the Collections.synchronizedSet method. This is best done at creation time, to prevent accidental unsynchronized access to the ArrayList:

        List list = Collections.synchronizedList(new ArrayList(...));
 

The Iterators returned by ArrayList's iterator and listIterator methods are fail-fast: if the ArrayList is structurally modified at any time after the Iterator is created, in any way except through the Iterator's own remove or add methods, the Iterator will throw a ConcurrentModificationException. Thus, in the face of concurrent modification, the Iterator fails quickly and cleanly, rather than risking arbitrary, non-deterministic behavior at an undetermined time in the future.

Since:

JDK1.2

See Also:

Collection, List, LinkedList, Vector, Collections.SynchronizedList, Serialized Form

Field Summary

Fields inherited from class oracle.jbo.server.java.util.AbstractList

modCount

Constructor Summary

ArrayList()
Constructs an empty ArrayList.

ArrayList(Collection c)
Constructs an ArrayList containing the elements of the specified Collection, in the order they are returned by the Collection's iterator.

ArrayList(int initialCapacity)
Constructs an empty ArrayList with the specified initial capacity.

ArrayList(int initialCapacity, int capacityIncrement)
Constructs an empty ArrayList with the specified initial capacity and capacity increment.

Method Summary

void	add(int index, java.lang.Object element) Inserts the specified element at the specified position in this ArrayList.
boolean	add(java.lang.Object o) Appends the specified element to the end of this ArrayList.
boolean	addAll(Collection c) Appends all of the elements in the specified Collection to the end of this this ArrayList, in the order that they are returned by the specified Collection's Iterator.
boolean	addAll(int index, Collection c) Inserts all of the elements in the specified Collection into this ArrayList, starting at the specified position.
void	clear() Removes all of the elements from this ArrayList.
java.lang.Object	clone() Returns a shallow copy of this ArrayList.
boolean	contains(java.lang.Object elem) Returns true if this ArrayList contains the specified element.
void	ensureCapacity(int minCapacity) Increases the capacity of this ArrayList, if necessary, to ensure that it can hold at least the number of components specified by the minimum capacity argument.
java.lang.Object	get(int index) Returns the element at the specified position in this ArrayList.
int	indexOf(java.lang.Object elem) Searches for the first occurence of the given argument, testing for equality using the equals method.
int	indexOf(java.lang.Object elem, int index) Searches for the first occurence of the given argument, beginning the search at index, and testing for equality using the equals method.
boolean	isEmpty() Tests if this ArrayList has no components.
int	lastIndexOf(java.lang.Object elem) Returns the index of the last occurrence of the specified object in this ArrayList.
int	lastIndexOf(java.lang.Object elem, int index) Searches backwards for the specified object, starting from the specified index, and returns an index to it.
java.lang.Object	remove(int index) Removes the element at the specified position in this ArrayList.
void	removeRange(int fromIndex, int toIndex) Removes from this ArrayList all of the elements whose index is between fromIndex, inclusive and toIndex, exclusive.
java.lang.Object	set(int index, java.lang.Object element) Replaces the element at the specified position in this ArrayList with the specified element.
int	size() Returns the number of components in this ArrayList.
java.lang.Object[]	toArray() Returns an array containing all of the elements in this ArrayList in the correct order.
void	trimToSize() Trims the capacity of this ArrayList to be the ArrayList's current size.

Methods inherited from class oracle.jbo.server.java.util.AbstractList

equals, iterator, listIterator, listIterator

Methods inherited from class oracle.jbo.server.java.util.AbstractCollection

containsAll, remove, removeAll, retainAll, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface oracle.jbo.server.java.util.List

containsAll, equals, hashCode, iterator, listIterator, listIterator, remove, removeAll, retainAll

Constructor Detail

ArrayList

public ArrayList(int initialCapacity,
                 int capacityIncrement)

Constructs an empty ArrayList with the specified initial capacity and capacity increment.

Parameters:

initialCapacity - the initial capacity of the ArrayList.

capacityIncrement - the amount by which the capacity is increased when the ArrayList overflows.

Since:

JDK1.2

ArrayList

public ArrayList(int initialCapacity)

Constructs an empty ArrayList with the specified initial capacity.

Parameters:

initialCapacity - the initial capacity of the ArrayList.

Since:

JDK1.2

ArrayList

public ArrayList()

Constructs an empty ArrayList.

Since:

JDK1.2

ArrayList

public ArrayList(Collection c)

Constructs an ArrayList containing the elements of the specified Collection, in the order they are returned by the Collection's iterator. The ArrayList has initial capacity of 110% the size of the specified Collection, and the default capacity increment.

Since:

JDK1.2

Method Detail

trimToSize

public void trimToSize()

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

Since:

JDK1.2

ensureCapacity

public void ensureCapacity(int minCapacity)

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

Parameters:

minCapacity - the desired minimum capacity.

Since:

JDK1.2

size

public int size()

Returns the number of components in this ArrayList.

Specified by:

size in interface List

Specified by:

size in class AbstractCollection

Returns:

the number of components in this ArrayList.

Since:

JDK1.2

isEmpty

public boolean isEmpty()

Tests if this ArrayList has no components.

Specified by:

isEmpty in interface List

Overrides:

isEmpty in class AbstractCollection

Returns:

true if this ArrayList has no components; false otherwise.

Since:

JDK1.2

contains

public boolean contains(java.lang.Object elem)

Returns true if this ArrayList contains the specified element.

Specified by:

contains in interface List

Overrides:

contains in class AbstractCollection

Parameters:

elem - element whose presence in this List is to be tested.

Since:

JDK1.2

indexOf

public int indexOf(java.lang.Object elem)

Searches for the first occurence of the given argument, testing for equality using the equals method.

Specified by:

indexOf in interface List

Overrides:

indexOf in class AbstractList

Parameters:

elem - an object.

Returns:

the index of the first occurrence of the argument in this ArrayList; returns -1 if the object is not found.

Since:

JDK1.2

See Also:

Object.equals(Object)

indexOf

public int indexOf(java.lang.Object elem,
                   int index)

Searches for the first occurence of the given argument, beginning the search at index, and testing for equality using the equals method.

Specified by:

indexOf in interface List

Overrides:

indexOf in class AbstractList

Parameters:

elem - an object.

index - the index to start searching from.

Returns:

the index of the first occurrence of the object argument in this ArrayList at position index or later in the ArrayList; returns -1 if the object is not found.

Since:

JDK1.2

See Also:

Object.equals(Object)

lastIndexOf

public int lastIndexOf(java.lang.Object elem)

Returns the index of the last occurrence of the specified object in this ArrayList.

Specified by:

lastIndexOf in interface List

Overrides:

lastIndexOf in class AbstractList

Parameters:

elem - the desired component.

Returns:

the index of the last occurrence of the specified object in this ArrayList; returns -1 if the object is not found.

Since:

JDK1.2

lastIndexOf

public int lastIndexOf(java.lang.Object elem,
                       int index)

Searches backwards for the specified object, starting from the specified index, and returns an index to it.

Specified by:

lastIndexOf in interface List

Overrides:

lastIndexOf in class AbstractList

Parameters:

elem - the desired component.

index - the index to start searching from.

Returns:

the index of the last occurrence of the specified object in this ArrayList at position less than index in the ArrayList; -1 if the object is not found.

Since:

JDK1.2

clone

public java.lang.Object clone()

Returns a shallow copy of this ArrayList. (The elements themselves are not copied.)

Returns:

a clone of this ArrayList.

Since:

JDK1.2

toArray

public java.lang.Object[] toArray()

Returns an array containing all of the elements in this ArrayList in the correct order.

Specified by:

toArray in interface List

Overrides:

toArray in class AbstractCollection

Since:

JDK1.2

get

public java.lang.Object get(int index)

Returns the element at the specified position in this ArrayList.

Specified by:

get in interface List

Specified by:

get in class AbstractList

Parameters:

index - index of element to return.

Throws:

java.lang.ArrayIndexOutOfBoundsException - index is out of range (index < 0 || index >= size()).

Since:

JDK1.2

set

public java.lang.Object set(int index,
                            java.lang.Object element)

Replaces the element at the specified position in this ArrayList with the specified element.

Specified by:

set in interface List

Overrides:

set in class AbstractList

Parameters:

index - index of element to replace.

element - element to be stored at the specified position.

Returns:

the element previously at the specified position.

Throws:

java.lang.ArrayIndexOutOfBoundsException - index out of range (index < 0 || index >= size()).

java.lang.IllegalArgumentException - fromIndex > toIndex.

Since:

JDK1.2

add

public boolean add(java.lang.Object o)

Appends the specified element to the end of this ArrayList.

Specified by:

add in interface List

Overrides:

add in class AbstractList

Parameters:

o - element to be appended to this ArrayList.

Returns:

true (as per the general contract of Collection.add).

Since:

JDK1.2

add

public void add(int index,
                java.lang.Object element)

Inserts the specified element at the specified position in this ArrayList. 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

Overrides:

add in class AbstractList

Parameters:

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

element - element to be inserted.

Throws:

java.lang.ArrayIndexOutOfBoundsException - index is out of range (index < 0 || index > size()).

Since:

JDK1.2

remove

public java.lang.Object remove(int index)

Removes the element at the specified position in this ArrayList. Shifts any subsequent elements to the left (subtracts one from their indices). Returns the element that was removed from the ArrayList.

Specified by:

remove in interface List

Overrides:

remove in class AbstractList

Parameters:

index - the index of the element to removed.

Returns:

the element previously at the specified position.

Throws:

java.lang.ArrayIndexOutOfBoundsException - index out of range (index < 0 || index >= size()).

Since:

JDK1.2

clear

public void clear()

Removes all of the elements from this ArrayList. The ArrayList will be empty after this call returns, unless it throws an exception.

Specified by:

clear in interface List

Overrides:

clear in class AbstractCollection

Throws:

UnsupportedOperationException - clear is not supported by this Set.

Since:

JDK1.2

addAll

public boolean addAll(Collection c)

Appends all of the elements in the specified Collection to the end of this this ArrayList, 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. (This implies that the behavior of this call is undefined if the the specified Collection is this ArrayList, and this ArrayList is nonempty.)

Specified by:

addAll in interface List

Overrides:

addAll in class AbstractCollection

Parameters:

c - elements to be inserted into this ArrayList.

Throws:

java.lang.ArrayIndexOutOfBoundsException - index out of range (index < 0 || index > size()).

Since:

JDK1.2

See Also:

AbstractCollection.add(Object)

removeRange

public void removeRange(int fromIndex,
                        int toIndex)

Removes from this ArrayList all of the elements whose index is between fromIndex, inclusive and toIndex, exclusive. Shifts any succeeding elements to the left (reduces their index). This call shortens the ArrayList by (toIndex - fromIndex) elements. (If toIndex==fromIndex, this operation has no effect.)

Specified by:

removeRange in interface List

Overrides:

removeRange in class AbstractList

Parameters:

fromIndex - index of first element to be removed.

toIndex - index after last element to be removed.

Throws:

java.lang.ArrayIndexOutOfBoundsException - fromIndex or toIndex out of range (fromIndex < 0 || fromIndex >= size() || toIndex > size() || toIndex < fromIndex).

Since:

JDK1.2

addAll

public boolean addAll(int index,
                      Collection c)

Inserts all of the elements in the specified Collection into this ArrayList, starting at the specified position. 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 the ArrayList in the order that they are returned by the specified Collection's iterator.

Specified by:

addAll in interface List

Overrides:

addAll in class AbstractList

Parameters:

index - index at which to insert first element from the specified collection.

c - elements to be inserted into this ArrayList.

Returns:

true if this List changed as a result of the call.

Throws:

java.lang.ArrayIndexOutOfBoundsException - index out of range (index < 0 || index > size()).

Since:

JDK1.2