从JRuby调用Java方法抛出“无参数错误的构造函数” [英] Calling Java method from JRuby throws "no constructor for arguments error"

问题描述

我要尝试初始化来自jRuby的JaCop约束编程库中的类。我使用正确类型的参数，但由于某种原因，我不断收到此错误消息：

I'm trying to initialize this class from the JaCop constraint programming library from jRuby. I am using the correct type of arguments, but for some reason I keep getting this error message:

  NameError: no constructor for arguments
    (
      org.jruby.RubyArray,
      org.jruby.RubyArray,
      org.jruby.RubyArray,
      JaCoP.core.IntVar,
      JaCoP.core.IntVar)
    on Java::JaCoPConstraintsKnapsack::Knapsack
    (root) at rb/knapsack.rb:24

它指向的代码是：

k = Jacop::Knapsack.new(@values, @weights, quantity, knapsackCapacity, knapsackProfit)

Java类的签名构造函数是这样的：

The signature of the Java class constructor is this:

public Knapsack(int[] profits,
                int[] weights,
                IntVar[] quantity,
                IntVar knapsackCapacity,
                IntVar knapsackProfit)

<

I don't understand why jRuby complains that constructor is not found because it should be able to find this.

推荐答案

JRuby不能总是猜到复杂的方法，你可以尝试：

JRuby can not always guess "complicated" method args for you, you might want to try :


Jacop :: Knapsack.new（@values，@weights ，quantity.to_java（JaCoP.core.IntVar），knapsackCapacity，knapsackProfit）


$ c> int [] cast（不需要）：

or even helping with the int[] cast (should not be necessary) :


Jacop :: Knapsack .new（@ values.to_java（：int），@ weights.to_java（：int），quantity.to_java（JaCoP.core.IntVar），knapsackCapacity，knapsackProfit）


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