package com.thoughtworks.xstream.test;

import java.util.ArrayList;
import java.util.List;

import junit.framework.AssertionFailedError;
import junit.framework.TestCase;

import com.thoughtworks.xstream.XStream;
import com.thoughtworks.xstream.annotations.Annotations;
import com.thoughtworks.xstream.annotations.XStreamImplicit;


public class XStreamImplicitUntypedTest extends TestCase {

  
  /*
   * Bug with @XStreamImplicit:
   * 
   * Configuring a class with an untyped Collection that is annotated with
   * @XStreamImplicit throws an unexpected NullPointerException. Indicate in
   * documentation and through initialization exception that @XStreamImplicit
   * is only available for typed Collections.
   */
  public void testNoTypeCollections() {
    final XStream xs = new XStream();
    
    assertNoException(new Runner<Object>() {
      public Object run() {
        Annotations.configureAliases(xs, Untyped.class);
        
        return "Success";
      }
    });
  }
  
  
  private static class Untyped {
    
    @XStreamImplicit
    private List list = new ArrayList();
    
    
    public Untyped() {
      list.add("1");
    }
  }
  
  
  
  /**
   * Determine whether the given code executes without throwing an
   * <code>Exception</code>.
   * 
   * @param r The code to execute.
   * @return The object returned by the code.
   */
  private<T> T assertNoException(Runner<T> r) {
    try {
      return r.run();
    } catch (Exception ex) {
      throw new AssertionFailedError("expected no exception but caught " + ex);
    }
  }
  
  
  /**
   * Encapsulates a piece of code.
   * 
   * @param <T> The return type of the code.
   */
  private static interface Runner<T> {
    public T run();
  }
}