Changes between Version 35 and Version 36 of PRO_LIB_CORE_TUTORIAL_NEW

Timestamp:

07/02/09 20:19:20 (16 years ago)

Author:

gogov

Comment:

--

PRO_LIB_CORE_TUTORIAL_NEW

@@ -571 +571 @@
 So, in this example you want to get the List of all invited people to your party, invite only people whose name is "Meddle" and update this list when a potential candidate to come to the party is added. This is kinda slow though, because each time a new Person is added to People, I don't want to reconstruct the whole invitedPeople list.
 
+ProLists are smart though so they act not only as lists but as maps. In the ProLib there is the concept of ''keys'' when using ProList, depending on what kind of items are inside:
+ * Immutables -- the ''key'' of an Immutable is the Immutable itself,
+ * ListEntries -- there is a ListEntry class which is basically a pair of a key and a value. The ''key'' of a ListEntry is its key (:
+ * others -- ''key'' is always null.
+
+You can get the ''key'' of a given object by using the ProUitl.getKey() method.
+
+ProLists check if they're working with ListEntry descendants, so you can subclass ListEntry to improve the above example like this:
+
+{{{
+...
+class Party implements ProObject {
+    static class PersonEntry extends ListEntry {
+        PersonEntry(String name, ... ) { ... }
+
+        Object getKey() { return name; }
+        Object getValue() { ... }
+    }
+
+    public ListProp<PersonEntry> people() { ... }
+
+    public ListProp<PersonEntry> invitedPeople() {
+        class invitedPeople extends AutoListProperty<PersonEntry> {
+            @Override
+            protected ProList<PersonEntry> constructList() {
+                return new ComposingProList<PersonEntry>() {
+                    @Override
+                    protected ProList<PersonEntry> computeData() {
+                        return people().findAll("Meddle");
+                    }
+                }
+            }
+        }
+
+        return getBean().makeProp(invitedPeople.class);
+    }
+...
+}}}
+
+Here the '''E findAll(Object key)''' method of ProList<E> is used which basically returns all elements in the list which have the specified key.
+
+The difference here is that ProLib is smart enough to recompute invitedPeople() only when another PersonEntry with key "Meddle" is entered, such is removed or modified. Otherwise it doesn't make sense to recompute because the list hasn't changed if for instance you've added a PersonEntry with key "Christ".
+
+'''E findOne(Object key)''' is the same but it expects to find at most one element with the specified key and returns it. If there are more than one, an Exception is thrown.
+
 === Bad Code Examples ===
- * init final property with constant which isn't an argument of the constructor
- * finalproperty.init(new stuff())
-
  * Resource Property is a better choice.
 {{{
@@ -597 +639 @@
 
 == Debugging ProLib ==
- * Inspector - A GUI tool that allows browsing the application state while it's still working.
+Some advice:
+ * Print. Debugging with a debugger is uglier that usual.
+ * Run the tests before commit. Don't break tests.
+ * Use the Inspector - this is a GUI tool that allows browsing the Properties in the application while it's running.
 
 == Good Practices  ==
@@ -604 +649 @@
  * Keep the ProLib and with high quality, because everything else will depend on it.
  * Be careful not to create cyclic dependencies (like a = b + 1, b = a + 1). No library can solve them.
+
+== TODO ==
+ * init final property with constant which isn't an argument of the constructor
+ * finalproperty.init(new stuff())