Using exceptions with strange objects

Question

Hi
I am thinking about whether I should add an exception to a certain constructor I have. Say I have the following class:
Parameter
String name;
String ValueType;
Object value;
public Parameter(String aName, String valueType, Object value)
{this.name = aName
Basically this object will be added to a hashMap and the objects 'name' will be they key. Therefore this object is useless if the name is null(in relation to another class I have which holds the hashMap storing Parameter objects) . Should I add an exception if users try to construct the object with a null name since the object is useless anyway.
My main issue is with the other two attrubutes. Basically the valueType is a string which could be "Date", "Integer" and selected java classes. value is a object corresponding to the value type. So valid fields could be "Date" and new Date(324234)). The problem is that these need to be initialised in the constructor and the user can give a invalid pair e.g. "Date",new Integer(2)). Now my other class(which had the hasmap) will read if the values corresond using a method like
boolean compareValues(String type, Object value)
if type.equals("Date") && (value instanceOf Date)
//good
else if type.equals("Integer") && (value instanceOf Integer)
//good
else
throw new ValueTypeAndValueNotCorrespond exception(valueType, value);
Now I can keep it as it is where the class holding the collection of objects check is if the fields correspond. Alternatively I could make the construtor of Parameters check if the values correspond, if not the constructor will throw an exception. I feel it should because otherwise you could create an object with fields which just don't correspond e.g. "Date", new Integer(3). Its a bit like have an 'Employee' class with an age and TimeWorked attributes where the age could be 16 and the timeWorked could be 24 years.
My question is, should I make the constructor throw the exception or should I allow the non corresponding attributes exist at object creation but valudate them when my other class is trying to make use of them.
Please advise. What are best practices?
Many thanks

Answer 1

I'd say throw an exception in the constructor.