javagit/src/main/java/edu/nyu/cs/javagit/api/Ref.java
public static Ref createTagRef(String name) {
    CheckUtilities.checkStringArgument(name, "name");

    Ref cn = new Ref();
    cn.refType = RefType.TAG;
    cn.name = name;
    return cn;
  }
public static Ref createTagRef(String name) {
    CheckUtilities.checkStringArgument(name, "name");

    Ref cn = new Ref();
    cn.refType = RefType.TAG;
    cn.name = name;
    return cn;
  }
Creates a <code>Ref</code> of type <code>TAG</code>.

@param name
The tag name of this ref. If the value is null, a <code>NullPointerException</code>
is thrown. If the value has length zero, an <code>IllegalArgumentException</code> is
thrown.
@return A <code>Ref</code> instance of type <code>TAG</code>.