[英]Syntax for Calling a variable-length parameter Scala function from Java?
I have a Scala class whose constructor takes a variable-length parameter list. 我有一个Scala类,其构造函数采用可变长度参数列表。
case class ItemChain(items: Item*)
From Scala it can be called like so 从Scala可以这样调用它
ItemChain(Item(), Item())
I can't figure out the syntax for calling it from Java. 我无法弄清楚从Java调用它的语法。 If I do this 如果我这样做
new ItemChain(new Item(), new Item())
I get a compiler error that says this line does not match the signature scala.collection.seq<Item>
. 我收到一个编译器错误,指出此行与签名scala.collection.seq<Item>
不匹配。
I can directly instantiate the Scala sequence object from Java. 我可以直接从Java实例化Scala序列对象。
new scala.collection.Seq<Item>()
But I can't figure out how to subsequently add my two Item
instances to it. 但我无法弄清楚如何随后添加我的两个Item
实例。 If I create a Java List
of Item
s and cast it to scala.collection.Seq
I get a runtime error. 如果我创建一个Item
的Java List
并将其转换为scala.collection.Seq
我得到一个运行时错误。
This should do the trick: 这应该做的伎俩:
import static scala.collection.JavaConverters.asScalaBufferConverter;
import static java.util.Arrays.asList;
...
new ItemChain(asScalaBufferConverter(asList(new Item(), new Item())).asScala());
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