Collections, Maps and Iterators - Absolute Java - page 916

Display 16.7 Methods in the Classes ArrayList<T> and Vector<T> (part 4 of 4)

ITERATORS FOR BOTH ArrayList<T> AND Vector<T>
public Iterator<T> iterator()
Returns an iterator for the calling object. Iterators are discussed in Section 16.3.

public ListIterator<T> listIterator()
Returns a ListIterator<T> for the calling object. ListIterator<T> is discussed in Section 16.3.

ListIterator<T> listIterator( int index)
Returns a list iterator for the calling object starting at index . The first element to be returned by
the iterator is the one at index . (Iterators are discussed in Section 16.3.)
CONVERTING TO AN ARRAY FOR BOTH ArrayList<T> AND Vector<T>
public Object[ ] toArray()
Returns an array containing all of the elements in the calling object. The elements of the array are
indexed the same as in the calling object.

public <E> E[ ] toArray(E[ ] a)
Note that the type parameter E is not the same as T . So, E can be any reference type; it need not
be the type T in Collection<T> . For example, E might be an ancestor type of T .
Returns an array containing all of the elements in the calling object. The elements of the array are
indexed the same as in the calling object.
The argument a is used primarily to specify the type of the array returned. The exact details are
described next.
The type of the returned array is that of a . If the collection fits in the array a , then a is used to hold
the elements of the returned array; otherwise a new array is created with the same type as a .
If a has more elements than the calling object, then the element in a immediately following the
end of the elements copied from the calling object is set to null .
MEMORY MANAGEMENT FOR BOTH ArrayList<T> AND Vector<T>
public int size()
Returns the number of elements in the calling object.

public int capacity()
Returns the current capacity of the calling object.

public void ensureCapacity( int newCapacity)
Increases the capacity of the calling object to ensure that it can hold at least newCapacity
elements. Using ensureCapacity can sometimes increase efficiency, but it is not needed for
any other reason.

public void trimToSize()
Trims the capacity of the calling object to be the calling object's current size. This is used to save storage.
MAKE A COPY FOR BOTH ArrayList<T> AND Vector<T>
public Object clone()
Returns a shallow copy of the calling object.