JDK 1.5 New Features

Новости в JDK 1.5 Светлин Наков www.devbg.org

Съдържание ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

История на езика Java ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Принципи, залегнали в JDK 1.5 ,[object Object],[object Object],[object Object],[object Object]

Auto boxing/unboxing ,[object Object],[object Object],[object Object],ArrayList list = new ArrayList(); list.add(5); // auto boxing: int --> Integer Integer i = (Integer) list.get(0); int i2 = i; // auto unboxing: Integer --> int

Разширение на for - циклите ,[object Object],Person[] persons = new Person[] { new Person("Бай Иван"), new Person("Цар Киро"), new Person("Баба Яга") }; for (Person p : persons) { System.out.println(p); }

Разширение на for - циклите ,[object Object],[object Object],ArrayList personsList = new ArrayList(); personsList.add(new Person("Бай Иван")); personsList.add(new Person("Цар Киро")); personsList.add(new Person("Баба Яга")); for (Object obj : personsList) { Person person = (Person) obj; System.out.println(person); }

Изброени типове (enums) ,[object Object],[object Object],[object Object],[object Object],[object Object],public enum Color { WHITE, RED, GREEN, BLUE, BLACK }

Изброени типове (enums) ,[object Object],switch (color) { case WHITE: System.out.println("бяло"); break; case RED: System.out.println("червено"); break; ... } if (color == Color.RED) { ... }

Изброени типове (enums) ,[object Object],public static void main(String[] args) { Color color = Color.RED; System.out.println("color = " + color); int value = color.ordinal(); System.out.println("value = " + value); for(Color c : Color.values()) { System.out.println("Color." + c + " = " + c.ordinal()); } }

Статично включване ,[object Object],import static java.lang.Math.*; public static void main(String[] args) { // Пишем директно PI, а не Math.PI // и sin(PI/2), а не Math.sin(Math.PI/2) System.out.println( "PI = " + PI + ", sin(PI/2) = " + sin(PI/2) ); }

Променлив брой аргументи ,[object Object],double average(double ... aValues) { double sum = 0; for (double value : aValues) { sum = sum + value; } double avg = sum / aValues.length; return avg; } System.out.println(average(5,6)); System.out.println(average(1,2,3,4,5));

Ковариантност на връщания тип ,[object Object],interface SomeInterface { public Object someMethod(); } public class C implements SomeInterface { public String someMethod() { return "I return String " + " instead of Object"; } }

Шаблонни типове ,[object Object],[object Object],public class Example<T> { private T mValue; public Example<T>(T aValue) { mValue = aValue; } public T getValue() { return mValue; } }

Шаблонни типове ,[object Object],[object Object],[object Object],Example<String> str = new Example<String>( "Шаблони, маблони, макарони и купони "); System.out.println(str.getValue()); Example< Double > d = new Example< Double >( 3.14159265 ); System.out.println( d .getValue());

Шаблонни типове ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Шаблонни колекции ,[object Object],import java.util.*; ArrayList<Integer> list = new ArrayList<Integer>(); list.add(5); int value = list.get(0); HashMap<String, Integer> ageMap = new HashMap<String, Integer>(); ageMap.put("Бай Киро", 83); int kiroAge = ageMap.get("Бай Киро");

Шаблонни колекции ,[object Object],ArrayList <Person> personsList = new ArrayList <Person> (); personsList.add(new Person("Бай Иван")); personsList.add(new Person("Цар Киро")); personsList.add(new Person("Баба Яга")); for ( Person person : personsList) { System.out.println(person); }

[object Object],Шаблонни типове class Example<T extends Person> { ... } class Example2<T extends Shape & Movable, Transformable> { ... } void fill(List<? extends Shape> aList) { ... }

Шаблонни методи ,[object Object],static <T> void swap(T[] arr, int index1, int index2) { T temp = arr[index1]; arr[index1] = arr[index2]; arr[index2] = temp; } public static void main(String[] args) { Integer[] intArray = {10, 20, 30, 40}; swap(intArray, 1 , 3 ); }

Демонстрация ,[object Object],[object Object]

Анотации ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Анотации ,[object Object],@Retention(RetentionPolicy.RUNTIME) @interface Author { String name(); } @Target(ElementType.METHOD) @Retention(RetentionPolicy.RUNTIME) @interface Optimize { String level() default "release" ; boolean threadSafe(); String lastCheckDate(); // java.util.Date not allowed! }

Анотации ,[object Object],@ A uthor(name="Svetlin Nakov") public class AnnotDemo { @ O ptimize(level="debug", threadSafe=false, lastCheckDate="20.07.2004") public void test () { ... } }

Анотации ,[object Object],[object Object],import java.lang.annotation.*; Annotation classAnnot = AnnotDemo.class. getAnnotation(Author.class); System.out.println("AnnotDemo class " + "has annotation: " + classAnnot); Author classAuthor = (Author) classAnnot; System.out.println("AnnotDemo has " + "author: " + classAuthor.name());

Анотации ,[object Object],// EJB 3.0 session bean @Session public class Sample Session Bean { private DataSource customerDB; @Inject private void setCustomerDB( DataSource customerDB) { this.customerDB = customerDB; } ... }

Демонстрация ,[object Object]

Нови класове в JDK 1.5 ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Форматиран вход/изход Date now = new java.util.Date(); System.out.printf("Today is " + "%1$te.%1$tm.%1$tY", now); String name = "Svetlin Nakov"; int count = 15; System.out.printf("Welcome, %1$s. You " + "are visitior %2$d.", name, count); Scanner sc = new Scanner(System.in); int value = sc.nextInt(); System.out.printf("value = %1$d", value);

Конкурентно програмиране ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Executors ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Executors ,[object Object],[object Object],[object Object],[object Object]

Executors – пример // Create a thread pool with 3 worker threads int threadsCount = 3; ExecutorService pool = Executors. newFixedThreadPool(threadsCount); // Add some tasks to the pool int tasksCount = 12; for (int i = 0; i < tasksCount; i++) { pool.execute(new Task("t" + (i+1))); } // Destroy the pool after all tasks get finished pool.shutdown();

Други новости в JDK 1.5 ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Проследяване на стека // Show current thread's stack trace java.lang.StackTraceElement ste[] = Thread.currentThread().getStackTrace(); for (int i=0; i < ste.length; i++) { System.out.println(ste[i]); } // Show all threads' stack traces Map<Thread,StackTraceElement[]> allStacks = Thread.getAllStackTraces(); System.out.println(allStacks);

[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Още новости в JDK 1.5

[object Object],[object Object],[object Object],[object Object],[object Object],Още новости в JDK 1.5

За повече информация ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Новости в JDK 1.5 ,[object Object]

JDK 1.5 New Features

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