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--- becki:linux:java [2010-03-15 15:46]
becki
+++ becki:linux:java [2010-10-19 12:50] (aktuell)
becki
@@ Zeile 1: / Zeile 1: @@
 ====== Java ==
-===== Links ==
+===== Related Pages ==
-[[sunkurs]] | [[comparison table]]
+<pagelist>
+  * [[java plumbing]]
+  * [[java web programming]]
+  * [[apache click]]
+  * [[apache tomcat]]
+  * [[jrunscript]]
+</pagelist>
 ===== Java Versions and Compatibility ==
@@ Zeile 79: / Zeile 85: @@
 ===== Rich Internet Applications ==
+FIXME Whole secton is obsoete. See [[java plumbing]] instead!
 ==== Java Web Start ==
@@ Zeile 114: / Zeile 123: @@
   - inherited from java.awt.Container
 see also Java Tutorial Sun: Lesson: Overview of Applets
-==== Deploy both as Applet and JWS ==
-It is advisable to separate core functionality from the final deployment mechanism:
-=== Appliction specific Code ==
-<code java>
-import javax.swing.*;
-public class MyApplication extends JFrame {
-    private void createAndShowGUI() {
-        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
-        setTitle("My App Title");
-        JPanel panel= new MyContent();  /* get app-specific content  */
-        getContentPane().add(panel);    /* and put it into app frame */
-        pack();
-        setVisible(true);
-    }
-    public static void main(String[] args) {
-        javax.swing.SwingUtilities.invokeLater(new Runnable() {
-            public void run() {
-                MyApplication frame = new MyApplication();
-                frame.createAndShowGUI();
-            }
-        });
-    }
-}
-</code>
-FIXME The usage of ''SwingUtilities.invokeLater'' is [[javatut>uiswing/start/compile.html|used]] by Sun as well.
-=== Applet specific Code ==
-<code java>
-import javax.swing.*;
-public class MyApplet extends JApplet {
-    public void init() {
-        try {
-            SwingUtilities.invokeAndWait(new Runnable() {
-                public void run() {
-                    JPanel panel= new MyContent();/* create app-specific */
-                    add(panel);     /* content and put it into app frame */
-                }
-            });
-        } catch (Exception e) {
-            System.err.println("createGUI didn't complete successfully");
-        }
-    }
-}
-</code>
-=== Shared Code ==
-<code java>
-import javax.swing.*;
-public class MyContent extends JPanel {
-    private JLabel myLabel;
-    MyContent() {
-        myLabel= new JLabel("¡Hola Mundo!");
-        add(myLabel);
-    }
-}
-</code>
 ===== Events ==
@@ Zeile 245: / Zeile 185: @@
 String s= ""+ 4711;
 String s= new Integer(4711).toString();
+String s= String.valueOf(4711);
 </code>
@@ Zeile 343: / Zeile 284: @@
 String readLine() throws IOException
 </code>
+===== Collections ==
+==== Overview ==
+[[javatut>reallybigindex.html#collections|Chapter in the Java tutorial]]
+|  //[[javaref>api/java/util/Collection.html|Collection]]//  ||||  //[[javaref>api/java/util/Map.html|Map]]//  ||
+|  //[[javaref>api/java/util/Set.html|Set]]//  ||  //[[javaref>api/java/util/List.html|List]]//  |  //[[javaref>api/java/util/Queue.html|Queue]]//  |  ||
+|  |  //[[javaref>api/java/util/SortedSet.html|SortedSet]]// |  |  |  |  //[[javaref>api/java/util/SortedMap.html|SortedMap]]//  |
+| HashSet LinkedHashSet | TreeSet | LinkedList Vector ArrayList | LinkedList, PriorityQueue | HashTable LinkedHashMap HashMap | TreeMap |
+==== Implementations ==
+  * [[javatut>collections/implementations/|Overview]]
+  * [[http://www.developer.com/java/article.php/3829891|Selecting the Best Java Collection Class for Your Application]]
+  * [[javatut>collections/implementations/map.html|General purpose map implementations]]
+==== Methods ==
+<code java>
+// important methods of List:
+boolean add(E e)
+void add(int index, E element)
+boolean contains(Object o)
+E get(int index)
+int indexOf(Object o)
+Iterator<E> iterator()
+E remove(int index)
+boolean remove(Object o) // Removes the first occurrence
+Object[] toArray()
+<T> T[] toArray(T[] a)
+// important methods of Map
+boolean containsKey(Object key)
+boolean  containsValue(Object value)
+V get(Object key)
+Set<K> keySet() // Returns a set of the keys
+V put(K key, V value) // there is no add!
+V remove(Object key)
+// important methods of Queue:
+boolean offer(E o) // Inserts the specified element at the end; also add() possible
+E peek() // Retrieves, but does not remove,
+E poll() // Retrieves and removes from the beginning; remove() also possible
+</code>
+  * Set: has no special order and no duplicates are permitted, not indexed; methods ar a subset of List (no index operations)
+  * List: ordered, duplicates are permitted, indexed
+  * Map does not implement the collection interface
+  * 'Sorted' is a subset of 'Ordered'
+  * Ordering:
+    * //Lists// are always ordered by index
+    * //Linked// collections are always ordered by insertion or last access
+    * //Tree// collections are always sorted
+  * List can made thread-save by Collections.synchronizedList()
+  * Tutorial: Vector is a legacy class; API: Vector is a normal class; Hashtable is similar; Vector also implements List
+  * HashSet & LinkedHashSet: Overwrite hashCode() so that equal objects provide the same hashcode
+  * LinkedList implements //List// and //Queue//
+  * //Queue// has Fifo (not stack) behaviour!
+  * All Interfaces have a size() method
+  * PriorityQueue sorts Elements by natural order using Comparable
+  * Elements for SortedSet/TreeSet, SortedMap/TreeMap
+ PriorityQueue must implement the Comparable interface!
+  * String implements interface Comparable<String> and Integer implements Comparable<Integer> -> Trying to add both Types to any untyped (old style) Tree-Container results in a ClassCastException
+  * Whereas adding only the same Type (eg Strings) works but gives a compiler warning. (I assume the type is detected at run time by reflection and the Object to compare is casted to String before compareTo() is called.)
+==== Sorting and Searching ==
+=== Sorting with the Comparable Interface ==
+To sort a //List// (eg ArrayList) or an array use:
+<code java>
+static void Collections.sort(List<T> list);
+static void Arrays.sort(allPrimitivesAndObject[] a);
+</code>
+The List interface has no sort method! All elements in the List or array must implement the Comparable interface:
+<code java>
+Interface Comparable<T> {
+    int compareTo(T o);
+}
+</code>
+Returns a negative integer, zero, or a positive integer as this object is less than, equal to, or greater than the specified object. Keep in mind that compareTo accepts Type T (the generic of the List) wheras equals always only accepts type Object!
+=== Sorting with the Comparator Interface ==
+<code java>
+static void Collections.sort(List<T> list, Comparator<? super T> c);
+static void Arrays.sort(T[] a, Comparator<? super T> c); // T is an Object, no primitives!
+Interface Comparator<T> {
+    int compare(T o1, T o2);
+}
+</code>
+=== Searching ==
+<code java>
+static int Collections.binarySearch(List<T> list, T key[, Comparator<? super T> c]);
+static int Arrays.binarySearch(allPrimitivesAndObject[] a, allPrimitivesAndObject key);
+static int Arrays.binarySearch(T[] a, T key, Comparator<? super T> c);
+</code>
+Call binarySearch() with the array or List as first param, the key as second, and, if not all items implement the Comparable interface, provide a Comparator as 3rd parameter. List or array has to be sorted before binarySearch can be called, otherwise the result is not predictable! If the element is not found, binarySearch returns -length-1
 ===== Threads ==
@@ Zeile 552: / Zeile 596: @@
 ==== Misc ==
+  * Possibly useful: [[ibm>java/library/j-javadev2-7.html|Kilim]] //actors// instead of threads for concurrent programming
   * [[http://www.developer.com/design/article.php/3680701|Thread local static variables]] (Threads Versus The Singleton Pattern)
   * Possibly useful: Simple thread control with [[http://www.developer.com/java/article.php/3713031|CountDownLatch]]
@@ Zeile 755: / Zeile 800: @@
         t1.state= Tribool.State.FALSE; t0.state= Tribool.State.FALSE;
         System.out.println((t0.and(t1)).toString());
     }
 }
 </code>
-===== Further Reading ==
+===== Further Reading / 2do ==
+  * Intro to the [[ibm>java/library/j-5things9.html|Java Scripting API]] with [[jrunscript]]
+  * Doc general Java strategy: Use [[Apache Pivot]] for the GUI, [[JUnit]] for testing, [[Apache Ant]] for building, JWS for distribution and [[Groovy]] for coding
   * [[http://www.linux-magazin.de/Heft-Abo/Ausgaben/2008/08/Reiches-Angebot|Webentwicklung mit Java]]: An Overview (german)
   * [[http://www.ibm.com/developerworks/opensource/library/os-lombok/|Eliminate Java verbosity with  Lombok]]
-  * REST with AJAX:
+  * REST (with AJAX):
-    * [[http://www.ibm.com/developerworks/web/library/wa-aj-richjava/|Wink]] is a framework for building RESTful Web services
+    * Wink is a framework for building RESTful Web services
+      * [[ibm>web/library/wa-aj-jackson/|Wink with Jackson]], a [[http://jackson.codehaus.org/|Java JSON-processor]]
+      * [[ibm>web/library/wa-aj-richjava/|Build rich Java Web applications with Apache Wink and Ajax]]
+      * [[ibm>web/library/wa-apachewink1/|RESTful Web services with Apache Wink]]
     * [[http://www.developer.com/article.php/3843846|JAX-RS]]: The Java API for RESTful Web Services
     * [[http://www.developer.com/article.php/3841046|Real World REST]] using Jersey, AJAX and JSON

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