Question

For anyone familiar with lambdaj (not I) you will have seen this stacktrace, or some variation, before:

ch.lambdaj.function.argument.ArgumentConversionException: Unable to
convert the placeholder org.dom4j.tree.AbstractAttribute in a valid
argument at
ch.lambdaj.function.argument.ArgumentsFactory.actualArgument(ArgumentsFactory.java:92)
at
ch.lambdaj.function.matcher.HasArgumentWithValue.havingValue(HasArgumentWithValue.java:70)
at ch.lambdaj.Lambda.having(Lambda.java:1204)

My understadning is that this happens through a limitation of lambdaj with final classes.

I get the above when testing the following code:

import static ch.lambdaj.Lambda.having;
import static ch.lambdaj.Lambda.selectFirst;
import static org.hamcrest.CoreMatchers.equalTo;

import java.util.List;

import org.dom4j.tree.AbstractAttribute;
public class DocumentUtils {

    public static String getAttributeValueFromListByName(
            List<AbstractAttribute> list, String name) {

        AbstractAttribute requiredAttribute = selectFirst(list,
                having((AbstractAttribute.class).getName(), equalTo(name)));

        String value = requiredAttribute.getValue();

        return value;

    }

}

I had been using dom4j’s Attribute interface, getting the same problem, then thought maybe lambdaj doesn’t like interfaces.. so I switched to the AbstractAttribute abstract class.

Is there an issue with lambdaj and abstract classes? Or is my method just pants? Any ideas how to solve this?

FYI: I’m using lambdaj 2.4 and dom4j 1.6

Thanks a lot in advance.

Answer 1

Issue 92 has been raised with lambdaj, as requested by Mario Fusco (LambdaJ Developer)