Enumeration
public
interface
Enumeration
java.util.Enumeration<E> |
An object that implements the Enumeration interface generates a
series of elements, one at a time. Successive calls to the
nextElement
method return successive elements of the
series.
For example, to print all elements of a Vector<E>
v:
for (Enumeration<E> e = v.elements(); e.hasMoreElements();) System.out.println(e.nextElement());
Methods are provided to enumerate through the elements of a
vector, the keys of a hashtable, and the values in a hashtable.
Enumerations are also used to specify the input streams to a
SequenceInputStream
.
See also:
Summary
Public methods | |
---|---|
default
Iterator<E>
|
asIterator()
Returns an |
abstract
boolean
|
hasMoreElements()
Tests if this enumeration contains more elements. |
abstract
E
|
nextElement()
Returns the next element of this enumeration if this enumeration object has at least one more element to provide. |
Public methods
asIterator
public Iterator<E> asIterator ()
Returns an Iterator
that traverses the remaining elements
covered by this enumeration. Traversal is undefined if any methods
are called on this enumeration after the call to asIterator
.
API Note:
- This method is intended to help adapt code that produces
Enumeration
instances to code that consumesIterator
instances. For example, theJarFile.entries()
method returns anEnumeration<JarEntry>
. This can be turned into anIterator
, and then theforEachRemaining()
method can be used: (Note that there is also aJarFile jarFile = ... ; jarFile.entries().asIterator().forEachRemaining(entry -> { ... });
JarFile.stream()
method that returns aStream
of entries, which may be more convenient in some cases.)
Implementation Requirements:
Returns | |
---|---|
Iterator<E> |
an Iterator representing the remaining elements of this Enumeration |
hasMoreElements
public abstract boolean hasMoreElements ()
Tests if this enumeration contains more elements.
Returns | |
---|---|
boolean |
true if and only if this enumeration object
contains at least one more element to provide;
false otherwise. |
nextElement
public abstract E nextElement ()
Returns the next element of this enumeration if this enumeration object has at least one more element to provide.
Returns | |
---|---|
E |
the next element of this enumeration. |
Throws | |
---|---|
NoSuchElementException |
if no more elements exist. |