blocks|key|4630869|text|如果您不喜欢Collections.list(Enumeration)在迭代开始之前将整个内容复制到一个(临时)列表中，您可以使用一个简单的实用程序方法来帮助自己：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|4630870|public+static+<T>+void+forEachRemaining(Enumeration<T>+e,+Consumer<?+super+T>+c)+{
++while(e.hasMoreElements())+c.accept(e.nextElement());
}|code-block|syntax|javascript|4630871|然后，您可以简单地执行forEachRemaining(enumeration,+lambda-expression);+(注意import+static特性)…|4630872|entityMap^0|6|T|0|0|B|1D|1S|D|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|S|8|@$9|T|A|U|B|C]|$9|V|A|W|B|C]]|D|@]|E|$]]|$1|M|3|-4|5|6|7|X|8|@]|D|@]|E|$]]]|N|$]]

In case you don’t like the fact that <code>Collections.list(Enumeration)</code> copies the entire contents into a (temporary) list before the iteration starts, you can help yourself out with a simple utility method:

<pre><code>public static &lt;T&gt; void forEachRemaining(Enumeration&lt;T&gt; e, Consumer&lt;? super T&gt; c) {
 while(e.hasMoreElements()) c.accept(e.nextElement());
}
</code></pre>

Then you can simply do <code>forEachRemaining(enumeration, lambda-expression);</code> (mind the <code>import static</code> feature)…

blocks|key|124799|text|由于Java-9将有新的默认方法Enumeration.asIterator()，它将使纯Java解决方案变得更简单：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|124800|nets.asIterator().forEachRemaining(iface+->+{+...+});|code-block|syntax|javascript|124801|entityMap|0|LINK|mutability|MUTABLE|url|http://hg.openjdk.java.net/jdk9/dev/jdk/file/4be07e0eb9b6/src/java.base/share/classes/java/util/Enumeration.java#l84^0|G|O|G|O|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]]|D|@$9|V|A|W|1|X]]|E|$]]|$1|F|3|G|5|H|7|Y|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Z|8|@]|D|@]|E|$]]]|L|$M|$5|N|O|P|E|$Q|R]]]]

Since Java-9 there will be new default method <a href="http://hg.openjdk.java.net/jdk9/dev/jdk/file/4be07e0eb9b6/src/java.base/share/classes/java/util/Enumeration.java#l84"><code>Enumeration.asIterator()</code></a> which will make pure Java solution simpler:

<pre><code>nets.asIterator().forEachRemaining(iface -&gt; { ... });
</code></pre>

blocks|key|124809|text|对于Java+8，枚举到流的最简单转换是：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|124810|Collections.list(NetworkInterface.getNetworkInterfaces()).stream()|offset|length|style|CODE|124811|entityMap^0|0|0|1U|0^^$0|@$1|2|3|4|5|6|7|J|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|K|8|@$D|L|E|M|F|G]]|9|@]|A|$]]|$1|H|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|I|$]]

For Java 8 the simplest transformation of enumeration to stream is:

<code>Collections.list(NetworkInterface.getNetworkInterfaces()).stream()</code>

blocks|key|124852|text|我知道这是一个古老的问题，但我想提出一个替代Collections.asList和流功能的方案。由于问题的标题是“迭代枚举”，我认识到有时您希望使用lambda表达式，但增强的for循环可能更可取，因为枚举对象可能抛出异常，并且for循环更容易封装在更大的try-catch代码段中(lambda需要在lambda中捕获声明的异常)。为此，这里使用lambda创建一个Iterable，该Iterable在for循环中可用，并且不会预加载枚举：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|124853|+/**
+*+Creates+lazy+Iterable+for+Enumeration
+*
+*+@param+<T>+Class+being+iterated
+*+@param+e+Enumeration+as+base+for+Iterator
+*+@return+Iterable+wrapping+Enumeration
+*/
public+static+<T>+Iterable<T>+enumerationIterable(Enumeration<T>+e)
{
++++return+()+->+new+Iterator<T>()
++++{
++++++++@Override
++++++++public+T+next()
++++++++{
++++++++++++return+e.nextElement();
++++++++}

++++++++@Override
++++++++public+boolean+hasNext()
++++++++{
++++++++++++return+e.hasMoreElements();
++++++++}
++++};
}|code-block|syntax|javascript|124854|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

I know this is an old question but I wanted to present an alternative to Collections.asList and Stream functionality. Since the question is titled "Iterate an Enumeration", I recognize sometimes you want to use a lambda expression but an enhanced for loop may be preferable as the enumerated object may throw an exception and the for loop is easier to encapsulate in a larger try-catch code segment (lambdas require declared exceptions to be caught within the lambda). To that end, here is using a lambda to create an Iterable which is usable in a for loop and does not preload the enumeration:

<pre><code> /**
 * Creates lazy Iterable for Enumeration
 *
 * @param &lt;T&gt; Class being iterated
 * @param e Enumeration as base for Iterator
 * @return Iterable wrapping Enumeration
 */
public static &lt;T&gt; Iterable&lt;T&gt; enumerationIterable(Enumeration&lt;T&gt; e)
{
 return () -&gt; new Iterator&lt;T&gt;()
 {
 @Override
 public T next()
 {
 return e.nextElement();
 }

 @Override
 public boolean hasNext()
 {
 return e.hasMoreElements();
 }
 };
}
</code></pre>

Is it possible to iterate an <code>Enumeration</code> by using Lambda Expression? What will be the Lambda representation of the following code snippet:

<pre><code>Enumeration&lt;NetworkInterface&gt; nets = NetworkInterface.getNetworkInterfaces();

while (nets.hasMoreElements()) {
 NetworkInterface networkInterface = nets.nextElement();

}
</code></pre>

I didn't find any stream within it.

Iterate an Enumeration in Java 8

Java

可以使用Lambda表达式来迭代Enumeration吗？以下代码片段的Lambda表示将是什么：Enumeration<NetworkInterface> nets = NetworkInterface.getNetworkInterfaces();while (nets.hasMoreElements()) { ...

问在Java 8中迭代枚举
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