nsIArray
An indexed collection of elements. Provides basic functionality for
retrieving elements at a specific position, searching for
elements. Indexes are zero-based, such that the last element in the
array is stored at the index length-1.
For an array which can be modified, see nsIMutableArray below.
Neither interface makes any attempt to protect the individual
elements from modification. The convention is that the elements of
the array should not be modified. Documentation within a specific
interface should describe variations from this convention.
It is also convention that if an interface provides access to an
nsIArray, that the array should not be QueryInterfaced to an
nsIMutableArray for modification. If the interface in question had
intended the array to be modified, it would have returned an
nsIMutableArray!
null is a valid entry in the array, and as such any nsISupports
parameters may be null, except where noted.
queryElementAt()
Retrieve a specific element of the array, and QueryInterface it
to the specified interface. null is a valid result for
this method, but exceptions are thrown in other circumstances
@throws NS_ERROR_NO_INTERFACE when an entry exists at the
specified index, but the requested interface is not
available.
@throws NS_ERROR_ILLEGAL_VALUE when index > length-1
| index | position of element |
| uuid | the IID of the requested interface |
| result | the object, QI'd to the requested interface |
indexOf()
Get the position of a specific element. Note that since null is
a valid input, exceptions are used to indicate that an element
is not found.
| startIndex | The initial element to search in the array To start at the beginning, use 0 as the startIndex |
| element | The element you are looking for |
| a number >= startIndex which is the position of the element in the array. @throws NS_ERROR_FAILURE if the element was not in the array. |
enumerate the array
| a new enumerator positioned at the start of the array @throws NS_ERROR_FAILURE if the array is empty (to make it easy to detect errors), or NS_ERROR_OUT_OF_MEMORY if out of memory. |
length
number of elements in the array.