clojure / scala interop？ [英] clojure/scala interop?

问题描述

 软件包指示符
 
我尝试交互操作这个简单的scala代码， 
 class DoubleRingBuffer（val capacity：Int = 1000）{
 var elements = new Array [Double]（capacity）; 
 private var head = capacity-1 
 private var max = 0 
 
 def size（）：Int = {
 return max + 1 
} b 
 $ b def add（obj：Double）：Double = {
 head- = 1 
 if（head< 0）head = capacity-1 
 return set 1，obj）
} 
 
 def set（i：Int，obj：Double）：Double = {
 System.out.println（HI）
 if（i> = capacity || i <0）
 throw new IndexOutOfBoundsException（i +out of bounds）
 if（i> = max）max = i 
 var index = + i）％capacity 
 var prev = elements（index）
元素（索引）= obj 
返回prev 
} 
 
 def get（i： Int = 0）：Double = {
 System.out.println（size is+ size（））
 if（i> = size（）|| i < new IndexOutOfBoundsException（i +out of bounds）
 var index =（head + i）％capacity 
返回元素（索引）
} 
} 
  

在clojure中，我这样做

 （import'indicators.DoubleRingBuffer）
（def b（DoubleRingBuffer。 100））
（pr（.size b））;;错误：找不到匹配字段：类indicator.DoubleRingBuffer的大小
（pr（.get b 33））;;返回0：should throw一个索引越界错误！ 
（pr（.get b 100））;; throws index out of bounds错误，因为它应该
  

$ b b

此外，我没有得到任何输出到控制台！使用scala测试此代码可按预期工作。

解决方案

尝试这些在REPL：

/ p>

（类b）可能会告诉你它 indicators.DoubleRingBuffer 。

（vec（.getDeclaredMethods（class b）））会给你一个所有方法的向量在你的类中声明，就像它是一个Java类，所以你可以看到他们的签名。

现在，使用这些方法名称和参数，在签名中调用您的方法。

我有一个感觉，问题是在Scala的处理方法参数的默认值。

编辑：作为注释中描述的OP，它不是。

如果这不起作用，您可以尝试将您的Scala字节码反编译为Java，以了解 DoubleRingBuffer 类看起来像。

I am attempting to interop to this simple scala code, but am having some troubles.

package indicators

class DoubleRingBuffer(val capacity:Int=1000) {
  var elements = new Array[Double](capacity);
  private var head=capacity-1
  private var max=0

  def size ():Int = {
    return max+1
  }

  def add(obj:Double):Double = {
    head-=1
    if (head<0) head=capacity-1
    return set(max+1,obj)
  }

  def set(i:Int,obj:Double):Double = {
    System.out.println("HI")
    if (i>=capacity || i<0)
      throw new IndexOutOfBoundsException(i+" out of bounds")
    if (i>=max) max=i
    var index = (head+i)%capacity
    var prev = elements(index)
    elements(index)=obj
    return prev
  }

  def get(i:Int=0):Double = {
    System.out.println("size is "+size())
    if (i>=size() || i<0)
      throw new IndexOutOfBoundsException(i+" out of bounds")
    var index = (head+i)%capacity
    return elements(index)
  }    
}

In clojure, i do this

(import 'indicators.DoubleRingBuffer)
(def b (DoubleRingBuffer. 100))
(pr (.size b)) ;;ERROR: No matching field found: size for class indicators.DoubleRingBuffer
(pr (.get b 33)) ;;returns 0: should throw an index out of bounds error!
(pr (.get b 100)) ;;throws index out of bounds error, as it should

In addition, i do not get any output to the console! Testing this code using scala works as expected. Whats going on here and how can i fix it so that clojure can use the scala code?

解决方案

Try these in REPL:

(class b) will probably tell you it's indicators.DoubleRingBuffer.

(vec (.getDeclaredMethods (class b))) will give you a vector of all methods declared in your class as if it was a Java class, so you can see their signatures.

Now, call your methods as seen in the signatures, with these method names and parameters.

I have a feeling the problem is in Scala's dealing with default value for method parameter.

EDIT: As OP described in a comment, it isn't.

If that doesn't work you can try to decompile your Scala bytecode to Java to find out how does DoubleRingBuffer class look like.

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