Enumeration (Java 2 Platform SE 5.0) - JDK 5 Documentation v1.5.0, Java 2 SDK 英文文档

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Java^TM 2 Platform
Standard Ed. 5.0

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java.util
Interface Enumeration<E>

All Known Subinterfaces:: NamingEnumeration<T>

All Known Implementing Classes:: StringTokenizer

public interface 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 v:

     for (Enumeration 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.

NOTE: The functionality of this interface is duplicated by the Iterator interface. In addition, Iterator adds an optional remove operation, and has shorter method names. New implementations should consider using Iterator in preference to Enumeration.

Since:: JDK1.0
See Also:: Iterator, SequenceInputStream, nextElement(), Hashtable, Hashtable.elements(), Hashtable.keys(), Vector, Vector.elements()

Method Summary

boolean hasMoreElements()
Tests if this enumeration contains more elements.

E nextElement()
Returns the next element of this enumeration if this enumeration object has at least one more element to provide.

Method Summary
`boolean`	`hasMoreElements()` Tests if this enumeration contains more elements.
`E`	`nextElement()` Returns the next element of this enumeration if this enumeration object has at least one more element to provide.

Method Detail

hasMoreElements

boolean hasMoreElements()

Tests if this enumeration contains more elements.

Returns:: true if and only if this enumeration object contains at least one more element to provide; false otherwise.

nextElement

E nextElement()

Returns the next element of this enumeration if this enumeration object has at least one more element to provide.

Returns:: the next element of this enumeration.
Throws:: NoSuchElementException - if no more elements exist.