尝试在翡翠中打印容器ID时出现java.lang.ClassCastException

Question

I have a code for finding the list of containers from the ams in jade using queryPlatformAction method. I am getting a problem for typecasting the container id while putting the sop statement at the end..

     Result result = (Result) content;
     List listOfPlatforms = (List) result.getValue();
     Iterator iter = listOfPlatforms.iterator();
     while (iter.hasNext()) 
       {
       ContainerID next = (ContainerID) iter.next();
       System.out.println(next.getID());
       }

It is throwing an exception to me.

The exception is: java.lang.ClassCastException: jade.util.leap.ArrayList cannot be cast to java.util.List please help.

Answer 1

The two types of List are not in the same class hierarchy and therefore cannot be cast between each other, hence a ClassCastException .

The jade.util.leap.List interface is used within JADE to provide a List collection that looks the same between the different back-ends of JADE, but which is actually implemented differently. From the Javadocs, ArrayList only extends Object .

To fix this, declare listOfPlatforms to be of type jade.util.leap.List .