Convert instance of class org.jruby.RubyArray to class java.util.ArrayList

Question

I'm new to Ruby & Jruby . I want to test some stuffs of jruby in java code

Here is my code :

import java.util.ArrayList;
import java.util.HashMap;
import org.jruby.embed.LocalVariableBehavior;
import org.jruby.embed.ScriptingContainer;

public class Test {
    public static void main(String[] args){
        ScriptingContainer container = new ScriptingContainer(LocalVariableBehavior.PERSISTENT);
        Test t = new Test();
        LogStatBean bean = t.new LogStatBean();
        container.setHomeDirectory("classpath:/META-INF/jruby.home");
        container.put("bean", bean);
        container.runScriptlet("arr = [1, 2, 3, 4, 5, 6]");
        container.runScriptlet("puts arr");
        container.runScriptlet("bean.setOutput(arr) ");
        System.out.println(bean.getOutput());

    }
    public class LogStatBean {
        public ArrayList<HashMap<String, Object>> getOutput() {
            return output;
        }
        public void setOutput(ArrayList<HashMap<String, Object>> output) {
            this.output = output;
        }
        public ArrayList<HashMap<String, Object>> output;

    }
}

I cannot set the java local variable with type ArrayList in jruby ,it raise an error

TypeError: cannot convert instance of class org.jruby.RubyArray to class java.util.ArrayList
  (root) at <script>:1

What i have to do ?

kares · Accepted Answer · 2014-02-06 13:35:49Z

1

array in Ruby (usually) converts to a Java array - so either stop expecting an ArrayList or do the conversion yourself in Ruby ... this piece of Ruby should be helpful :

>> [1, 2, 3].class
=> Array
>> [1, 2, 3].to_java.java_class
=> class [Ljava.lang.Object;
>> [1, 2, 3].to_java('java.lang.Integer').java_class
=> class [Ljava.lang.Integer;
>> java.util.ArrayList.new [1, 2, 3]
=> #<Java::JavaUtil::ArrayList:0x1b802d73>
>> java.util.Arrays.asList([1, 2, 3].to_java)
=> #<Java::JavaUtil::Arrays::ArrayList:0x10478ebc>

answered Feb 6, 2014 at 13:35

kares

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