The problem if you dive into Java is that it may bring to your attention a myriad of details that may not be worth the trouble of learning if you do not expect to dive into Java and stay on the Clojure side of the fence.
No ready-fit light reading comes to my mind. Maybe a "learn java in 21 days" primer might be just enough but you would still have to fill the gap from the perspective of calling java libs from Clojure. Every Clojure books that I know of has a chapter on interop but that may not be enough alone depending of your interop needs. I would suggest narrowing the subject on how to understand Javadoc (most libs APIs are documented) and how to translate this to Clojure usable forms. The java primer might be a start to understand the API terminology(class, static, abstract class, ....). You may be able to pick up only the pieces you need along the way instead of digesting the whole thing at once. Luc > Thank you, gentlemen. Jim and Luc, your answers are both helpful. Luc's > answer illustrates why a Java tyro often has problems understanding > Clojure. Somebody like me who is trying to master Clojure, having come > to it via a language path that doesn't include Java, needs a > prerequisite crash course in Java concepts. (I hope it isn't necessary > for him actually to learn Java programming skills. Reserving > programming-skill learning for Clojure is a lot more fun!) Anybody have > any recommendations of a book that could be used for such a crash course? > --Larry > > > On 12/16/12 1:53 PM, Softaddicts wrote: > > First example tries to access a public static field in the Math class. > > > > Second example calls the static member function of the Math class. > > > > The difference is in the missing set of parenthesis. > > > > A static field or member function is attached to the class, not to a > > specific object > > and can be accessed through the class itself. Hence the / notation. > > > > On the other hand, (.addListener x ...) refers to the member fn addListener > > of the given object x. > > > > You will rarely find Java object specific public fields directly > > accessible, most of the > > time you need to use a getter to access them, hence the profusion of > > .getXzzz > > when you look at interop code. > > > > Static fields attached to a class are most of the time immutable, they are > > a way > > to make constants public and avoid the getter wrapper syndrom. > > > > Last thing, a class can define classes so you may need to access > > Aclass$Bclass/field to get access to a class static field defined within a > > class. > > > > This does not apply to an object of class B, the usual (.memberFn object > > ...) > > would still apply assuming you are handed an object created from an inner > > class. > > > > > > Luc P. > > > > > > > >> It almost certainly has something to do with my abysmal ignorance about > >> things Java, but I don't understand this difference: > >> > >> (1) > >> user> (map Math/sqrt [5 6 16]) > >> > >> Unable to find static field: sqrt in class java.lang.Math > >> [Thrown class java.lang.RuntimeException] > >> > >> (2) > >> user> (map #(Math/sqrt %) [5 6 16]) > >> (2.23606797749979 2.449489742783178 4.0) > >> > >> Thanks for helping me understand. > >> --Larry > >> > >> -- > >> You received this message because you are subscribed to the Google > >> Groups "Clojure" group. > >> To post to this group, send email to clojure@googlegroups.com > >> Note that posts from new members are moderated - please be patient with > >> your first post. > >> To unsubscribe from this group, send email to > >> clojure+unsubscr...@googlegroups.com > >> For more options, visit this group at > >> http://groups.google.com/group/clojure?hl=en > >> > > -- > > Softaddicts<lprefonta...@softaddicts.ca> sent by ibisMail from my ipad! > > > > -- > You received this message because you are subscribed to the Google > Groups "Clojure" group. > To post to this group, send email to clojure@googlegroups.com > Note that posts from new members are moderated - please be patient with your > first post. > To unsubscribe from this group, send email to > clojure+unsubscr...@googlegroups.com > For more options, visit this group at > http://groups.google.com/group/clojure?hl=en > -- Softaddicts<lprefonta...@softaddicts.ca> sent by ibisMail from my ipad! -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
