Question

I am writing this query service that’s suppose to work with couple predefined classes. However, it seems to me to be redundant that, when using this service class, I need to pass both the Type of the class and a class object it self. For example, to query “Contact” object, I’ll need to provide both and Contact.class, like the following:

lookupService = new MyLookupServiceImpl<Contact>(Contact.class);

In this case, is there a way to initialize Class without passing in “Contact.class”?
The service class look like the following:

public class MyLookupServiceImpl<T> {
private Class<T> cls;

public MyLookupServiceImpl(Class<T> clz){
    this.cls = clz;
}

public T queryObject(String sql) {
    try {
        QueryResult result = ConnectionFactory.getConnection().query(sql);
        if(result.getSize()>0){
            T obj=null;
            MyObject sObj = result.getRecords()[0];
            MyObjectBuilder<T> ob = new MyObjectBuilder<T>(cls);
            obj = ob.buildORMObject(sObj);
            return obj;
        }
    } catch (ConnectionException e) {
        logger.warn(e.toString());
    }
    return null;
}
}

Any suggestion would be appreciated.

Thank you,

Answer 1

The answer is NO. In java, because of type erasure, there is no other way infer/get this info at runtime other that passing in the type info as a Class<?> instance.