ListConverter.java

package org.jwebsocket.plugins.rpc.util;

import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.List;

import javolution.util.FastList;

@SuppressWarnings("rawtypes")
public class ListConverter<E> {
	private List mList;
	public ListConverter (List aList) {
		mList = aList;
	}
	/**
	 * 
	 * @return
	 * @throws Exception
	 */
	@SuppressWarnings("unchecked")
	public List<E> convert() throws Exception {
		List<E> lReturnedList = new FastList<E>();
		for (Object lObject : mList) {
			lReturnedList.add((E)lObject); 
		}
		return lReturnedList ;
	}

	/**
	 * Convert a list on a specific type.
	 * Throw an exception if one of the parameter of the list is not of the right type.
	 * For instance convert(List[12,354,21,"az"], Integer) will throw an exception since the list is not only composed of String.
	 * Works with list inside list.
	 * @return a FastList<aType>
	 * @throws Exception if a parameter of the List can't be cast as aType
	 * TODO: souldn't throw a generic Exception exception
	 */
	@SuppressWarnings("unchecked")
	public static List convert(List aList, Type aType) throws Exception {
		if(aType instanceof ParameterizedType) {
			ParameterizedType lParameterizedType = (ParameterizedType) aType;
			Type[] parameterArgTypes = lParameterizedType.getActualTypeArguments();
			List lReturnedList = new FastList();
			for (Object lObject : aList) {
				//If it's a list inside another list
				if (parameterArgTypes[0] instanceof ParameterizedType ){//&&
						//parameterArgTypes[0] instanceof List) {
						//((ParameterizedType) parameterArgTypes[0]).getActualTypeArguments()[0] == List.class) {
					lReturnedList.add(convert((List)lObject, (ParameterizedType) parameterArgTypes[0]));
				} else {
					Class parameterArgClass = (Class) parameterArgTypes[0] ;
					lReturnedList.add(parameterArgClass.cast(lObject));
				}
			}
			return lReturnedList ;
		} else {
			return aList;
		}
	}
}