jtl.zheng said:
the arrow is just like "------->"
and it has two kinds: the dotted line and the straight
line what are these two kinds mean in UML
There are a *lot* of straight and dotted lined arrows in UML, so it's a bit
difficult to answer it in short, e.g. with full triangle heads, the straight
lines mean "inheritance" (extends), while the dotted ones mean
"implementation" (implements).
------------------------------------------------
Otherwise in a static chart diagram the straight lined arrow can mean
"uni-directional association", while the dotted line means "dependency". A
small example:
class A {}
class B
{
// uni-directional association
A a;
}
class C
{
// dependency, but no association
void method(A a) {...}
}
C ----> A (dotted line)
B ----> A (but with a straight line)
-----------------------------------------------
In a sequence diagram, the straight lined arrow means a message (method
call), while the dotted arrow is where the method returns to the caller.
-----------------------------------------------
Here's a summarized reference card:
http://tnerual.eriogerg.free.fr/umlqrc.pdf
Here you can find the complete UML specification:
http://www-306.ibm.com/software/rational/uml/resources/documentation.html
/// Bjorn A