[J2ME] RecordStore - Database in J2ME

public class RecordStore

extends Object

A class representing a record store. A record store consists of a collection of records which will remain persistent across multiple invocations of the MIDlet. The platform is responsible for making its best effort to maintain the integrity of the MIDlet's record stores throughout the normal use of the platform, including reboots, battery changes, etc.

Record stores are created in platform-dependent locations, which are not exposed to the MIDlets. The naming space for record stores is controlled at the MIDlet suite granularity. MIDlets within a MIDlet suite are allowed to create multiple record stores, as long as they are each given different names. When a MIDlet suite is removed from a platform all the record stores associated with its MIDlets will also be removed. MIDlets within a MIDlet suite can access each other's record stores directly. New APIs in MIDP 2.0 allow for the explicit sharing of record stores if the MIDlet creating the RecordStore chooses to give such permission.

Sharing is accomplished through the ability to name a RecordStore created by another MIDlet suite.

RecordStores are uniquely named using the unique name of the MIDlet suite plus the name of the RecordStore. MIDlet suites are identified by the MIDlet-Vendor and MIDlet-Name attributes from the application descriptor.

Access controls are defined when RecordStores to be shared are created. Access controls are enforced when RecordStores are opened. The access modes allow private use or shareable with any other MIDlet suite.

Record store names are case sensitive and may consist of any combination of between one and 32 Unicode characters inclusive. Record store names must be unique within the scope of a given MIDlet suite. In other words, MIDlets within a MIDlet suite are not allowed to create more than one record store with the same name, however a MIDlet in one MIDlet suite is allowed to have a record store with the same name as a MIDlet in another MIDlet suite. In that case, the record stores are still distinct and separate.

No locking operations are provided in this API. Record store implementations ensure that all individual record store operations are atomic, synchronous, and serialized, so no corruption will occur with multiple accesses. However, if a MIDlet uses multiple threads to access a record store, it is the MIDlet's responsibility to coordinate this access or unintended consequences may result. Similarly, if a platform performs transparent synchronization of a record store, it is the platform's responsibility to enforce exclusive access to the record store between the MIDlet and synchronization engine.

Records are uniquely identified within a given record store by their recordId, which is an integer value. This recordId is used as the primary key for the records. The first record created in a record store will have recordId equal to one (1). Each subsequent record added to a RecordStore will be assigned a recordId one greater than the record added before it. That is, if two records are added to a record store, and the first has a recordId of 'n', the next will have a recordId of 'n + 1'. MIDlets can create other sequences of the records in the RecordStore by using the RecordEnumeration class.

This record store uses long integers for time/date stamps, in the format used by System.currentTimeMillis(). The record store is time stamped with the last time it was modified. The record store also maintains a version number, which is an integer that is incremented for each operation that modifies the contents of the RecordStore. These are useful for synchronization engines as well as other things.

Since:

MIDP 1.0

[JAVA] Java Programming Language Platform

One characteristic of Java is portability, which means that computer programs written in the Java language must run similarly on any supported hardware/operating-system platform. One should be able to write a program once, compile it once, and run it anywhere.

This is achieved by compiling the Java language code, not to machine code but to Java bytecode – instructions analogous to machine code but intended to be interpreted by a virtual machine (VM) written specifically for the host hardware. End-users commonly use a Java Runtime Environment (JRE) installed on their own machine for standalone Java applications, or in a Web browser for Java applets.

Standardized libraries provide a generic way to access host specific features such as graphics, threading and networking. In some JVM versions, bytecode can be compiled to native code, either before or during program execution, resulting in faster execution.

A major benefit of using bytecode is porting. However, the overhead of interpretation means that interpreted programs almost always run more slowly than programs compiled to native executables would, and Java suffered a reputation for poor performance. This gap has been narrowed by a number of optimization techniques introduced in the more recent JVM implementations.

One such technique, known as just-in-time (JIT) compilation, translates Java bytecode into native code the first time that code is executed, then caches it. This results in a program that starts and executes faster than pure interpreted code can, at the cost of introducing occasional compilation overhead during execution. More sophisticated VMs also use dynamic recompilation, in which the VM analyzes the behavior of the running program and selectively recompiles and optimizes parts of the program. Dynamic recompilation can achieve optimizations superior to static compilation because the dynamic compiler can base optimizations on knowledge about the runtime environment and the set of loaded classes, and can identify hot spots - parts of the program, often inner loops, that take up the most execution time. JIT compilation and dynamic recompilation allow Java programs to approach the speed of native code without losing portability.

Another technique, commonly known as static compilation, or ahead-of-time (AOT) compilation, is to compile directly into native code like a more traditional compiler. Static Java compilers translate the Java source or bytecode to native object code. This achieves good performance compared to interpretation, at the expense of portability; the output of these compilers can only be run on a single architecture. AOT could give Java something close to native performance, yet it is still not portable since there are no compiler directives, and all the pointers are indirect with no way to micro manage garbage collection.

Java's performance has improved substantially since the early versions, and performance of JIT compilers relative to native compilers has in some tests been shown to be quite similar.[12][13] The performance of the compilers does not necessarily indicate the performance of the compiled code; only careful testing can reveal the true performance issues in any system.

One of the unique advantages of the concept of a runtime engine is that even the most serious errors (exceptions) in a Java program should not 'crash' the system under any circumstances, provided the JVM itself is properly implemented. Moreover, in runtime engine environments such as Java there exist tools that attach to the runtime engine and every time that an exception of interest occurs they record debugging information that existed in memory at the time the exception was thrown (stack and heap values). These Automated Exception Handling tools provide 'root-cause' information for exceptions in Java programs that run in production, testing or development environments. Such precise debugging is much more difficult to implement without the run-time support that the JVM offers.

An edition of the Java platform is the name for a bundle of related programs, or platform, from Sun which allow for developing and running programs written in the Java programming language. The platform is not specific to any one processor or operating system, but rather an execution engine (called a virtual machine) and a compiler with a set of standard libraries that are implemented for various hardware and operating systems so that Java programs can run identically on all of them.

* Java Card: refers to a technology that allows small Java-based applications (applets) to be run securely on smart cards and similar small memory footprint devices.
* Java ME (Micro Edition): Specifies several different sets of libraries (known as profiles) for devices which are sufficiently limited that supplying the full set of Java libraries would take up unacceptably large amounts of storage.
* Java SE (Standard Edition): For general purpose use on desktop PCs, servers and similar devices.
* Java EE (Enterprise Edition): Java SE plus various APIs useful for multi-tier client-server enterprise applications.

As of September 2008[update], the current version of the Java Platform is specified as either 1.6.0 or 6 (both refer to the same version). Version 6 is the product version, while 1.6.0 is the developer version.

The Java Platform consists of several programs, each of which provides a distinct portion of its overall capabilities. For example, the Java compiler, which converts Java source code into Java bytecode (an intermediate language for the Java Virtual Machine (JVM)), is provided as part of the Java Development Kit (JDK). The Java Runtime Environment (JRE), complementing the JVM with a just-in-time (JIT) compiler, converts intermediate bytecode into native machine code on the fly. Also supplied are extensive libraries, pre-compiled in which are several other components, some available only in certain editions.

The essential components in the platform are the Java language compiler, the libraries, and the runtime environment in which Java intermediate bytecode "executes" according to the rules laid out in the virtual machine specification.

[JAVA] Displaying Images with the DisplayJAI class

INTRODUCTION

DisplayJAI is a class distributed with the Java Advanced Imaging API that can display an instance of the RenderedImage class, including instances of PlanarImage and TiledImage (tiling is supported). Since it inherits from JComponent it can be used in graphical interfaces as any other component.

This chapter shows some basic usage examples. Other chapters in this section shows how to extend the class for more specific tasks.

Important: A message on this class' API documentation says: This class is not a committed part of the Java^TM Advanced Imaging API per se. It might therefore not be supported by JAI implementations other than that of Sun Microsystems, Inc.

Displaying Images with the DisplayJAI class

A simple application will demonstrate the usage of the DisplayJAI class. It will load an image from disk, create a simple graphical interface with the DisplayJAI on the center and a text label on the bottom. The instance of DisplayJAI will be contained inside a JScrollPane so if the image is larger than the application's window the user will be able to the scrollbars to display different viewports of the image. The text label will show information about the image.

CODE :

   1 /*
   2  * Part of the Java Image Processing Cookbook, please see
   3  * http://www.lac.inpe.br/~rafael.santos/JIPCookbook/index.jsp
   4  * for information on usage and distribution.
   5  * Rafael Santos (rafael.santos@lac.inpe.br)
   6  */
   7 package display.basic;
   8  
   9 import java.awt.BorderLayout;
  10 import java.awt.Container;
  11  
  12 import javax.media.jai.JAI;
  13 import javax.media.jai.PlanarImage;
  14 import javax.swing.JFrame;
  15 import javax.swing.JLabel;
  16 import javax.swing.JScrollPane;
  17  
  18 import com.sun.media.jai.widget.DisplayJAI;
  19  
  20 /**
  21  * This application shows how to use the DisplayJAI class with a JScrollPane to display images.
  22  */
  23 public class DisplayJAIExample
  24   {
  25   /**
  26    * Entry point for this application.
  27    * @param args an image file name.
  28    */
  29   public static void main(String[] args)
  30     {
  31     // Load the image which file name was passed as the first argument to the
  32     // application.
  33     PlanarImage image = JAI.create("fileload", args[0]);
  34     // Get some information about the image
  35     String imageInfo = "Dimensions: "+image.getWidth()+"x"+image.getHeight()+
  36                        " Bands:"+image.getNumBands();
  37     // Create a frame for display.
  38     JFrame frame = new JFrame();
  39     frame.setTitle("DisplayJAI: "+args[0]);
  40     // Get the JFrame's ContentPane.
  41     Container contentPane = frame.getContentPane();
  42     contentPane.setLayout(new BorderLayout());
  43     // Create an instance of DisplayJAI.
  44     DisplayJAI dj = new DisplayJAI(image);
  45     // Add to the JFrame's ContentPane an instance of JScrollPane containing the
  46     // DisplayJAI instance.
  47     contentPane.add(new JScrollPane(dj),BorderLayout.CENTER);
  48     // Add a text label with the image information.
  49     contentPane.add(new JLabel(imageInfo),BorderLayout.SOUTH);
  50     // Set the closing operation so the application is finished.
  51     frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  52     frame.setSize(400,400); // adjust the frame size.
  53     frame.setVisible(true); // show the frame.
  54     }
  55   } 

Screenshot :

[JAVA] Java Programming Language "Hello World"

/*
 * Outputs "Hello, world!" and then exits
 */

public class HelloWorld {
  public static void main(String[] args) {
      System.out.println("Hello, world!");
  }
}

By convention, source files are named after the public class they contain, appending the suffix .java, for example, HelloWorld.java. It must first be compiled into bytecode, using a Java compiler, producing a file named HelloWorld.class. Only then can it be executed, or 'launched'. The java source file may only contain one public class but can contain multiple classes with less than public access and any number of public inner classes.

A class that is declared private may be stored in any .java file. The compiler will generate a class file for each class defined in the source file. The name of the class file is the name of the class, with .class appended. For class file generation, anonymous classes are treated as if their name was the concatenation of the name of their enclosing class, a $, and an integer.

The keyword public denotes that a method can be called from code in other classes, or that a class may be used by classes outside the class hierarchy. The class hierarchy is related to the name of the directory in which the.java file is.

The keyword static in front of a method indicates a static method, which is associated only with the class and not with any specific instance of that class. Only static methods can be invoked without a reference to an object. Static methods cannot access any method variables that are not static.

The keyword void indicates that the main method does not return any value to the caller. If a Java program is to exit with an error code, it must call System.exit() explicitly.

The method name "main" is not a keyword in the Java language. It is simply the name of the method the Java launcher calls to pass control to the program. Java classes that run in managed environments such as applets and Enterprise Java Beans do not use or need a main() method. A java program may contain multiple classes that have main methods, which means that the VM needs to be explicitly told which class to launch from.

The main method must accept an array of String objects. By convention, it is referenced as args although any other legal identifier name can be used. Since Java 5, the main method can also use variable arguments, in the form of public static void main(String... args), allowing the main method to be invoked with an arbitrary number of String arguments. The effect of this alternate declaration is semantically identical (the args parameter is still an array of String objects), but allows an alternate syntax for creating and passing the array.

The Java launcher launches Java by loading a given class (specified on the command line or as an attribute in a JAR) and starting its public static void main(String[]) method. Stand-alone programs must declare this method explicitly. The String[] args parameter is an array of String objects containing any arguments passed to the class. The parameters to main are often passed by means of a command line.

Printing is part of a Java standard library: The System class defines a public static field called out. The out object is an instance of the PrintStream class and provides many methods for printing data to standard out, including println(String) which also appends a new line to the passed string.

The string "Hello world!" is automatically converted to a String object by the compiler.

[JAVA] Java Programming Language Syntax

The syntax of Java is largely derived from C++. Unlike C++, which combines the syntax for structured, generic, and object-oriented programming, Java was built almost exclusively as an object oriented language. All code is written inside a class and everything is an object, with the exception of the intrinsic data types (ordinal and real numbers, boolean values, and characters), which are not classes for performance reasons.

Java suppresses several features (such as operator overloading and multiple inheritance) for classes in order to simplify the language and to prevent possible errors and anti-pattern design.

Java uses the same commenting methods as C++. There are two different methods of commenting, the first is generally used for single line comments // two forward slashes and the second is generally used for multiple line commenting, this requires an open and close. In order to use the second method of commenting you must use the forward slash asterisk (/*) and it must end with an asterisk forward slash (*/)

//This is an example of a single line comment using two forward slashes
/* This is an example of a multiple line comment using the forward slash
 and asterisk. This type of comment can be used to hold a lot of information
 but it is very important to remember to close the comment. */

[JAVA] Java Programming Language Automatic Memory Management

Java uses an automatic garbage collector to manage memory in the object lifecycle. The programmer determines when objects are created, and the Java runtime is responsible for recovering the memory once objects are no longer in use. Once no references to an object remain, the unreachable object becomes eligible to be freed automatically by the garbage collector. Something similar to a memory leak may still occur if a programmer's code holds a reference to an object that is no longer needed, typically when objects that are no longer needed are stored in containers that are still in use. If methods for a nonexistent object are called, a "null pointer exception" is thrown. [16][17]

One of the ideas behind Java's automatic memory management model is that programmers be spared the burden of having to perform manual memory management. In some languages memory for the creation of objects is implicitly allocated on the stack, or explicitly allocated and deallocated from the heap. Either way the responsibility of managing memory resides with the programmer. If the program does not deallocate an object, a memory leak occurs. If the program attempts to access or deallocate memory that has already been deallocated, the result is undefined and difficult to predict, and the program is likely to become unstable and/or crash. This can be partially remedied by the use of smart pointers, but these add overhead and complexity.

Garbage collection may happen at any time. Ideally, it will occur when a program is idle. It is guaranteed to be triggered if there is insufficient free memory on the heap to allocate a new object; this can cause a program to stall momentarily. Where performance or response time is important, explicit memory management and object pools are often used.

Java does not support C/C++ style pointer arithmetic, where object addresses and unsigned integers (usually long integers) can be used interchangeably. This allows the garbage collector to relocate referenced objects, and ensures type safety and security.

As in C++ and some other object-oriented languages, variables of Java's primitive types are not objects. Values of primitive types are either stored directly in fields (for objects) or on the stack (for methods) rather than on the heap, as commonly true for objects (but see Escape analysis). This was a conscious decision by Java's designers for performance reasons. Because of this, Java was not considered to be a pure object-oriented programming language. However, as of Java 5.0, autoboxing enables programmers to proceed as if primitive types are instances of their wrapper classes.

[JAVA] Java Implementation

Sun Microsystems officially licenses the Java Standard Edition platform for Microsoft Windows, Linux, Mac OS X, and Solaris. Through a network of third-party vendors and licensees[14], alternative Java environments are available for these and other platforms.

Sun's trademark license for usage of the Java brand insists that all implementations be "compatible". This resulted in a legal dispute with Microsoft after Sun claimed that the Microsoft implementation did not support RMI or JNI and had added platform-specific features of their own. Sun sued in 1997, and in 2001 won a settlement of $20 million as well as a court order enforcing the terms of the license from Sun.[15] As a result, Microsoft no longer ships Java with Windows, and in recent versions of Windows, Internet Explorer cannot support Java applets without a third-party plugin. Sun, and others, have made available free Java run-time systems for those and other versions of Windows.

Platform-independent Java is essential to the Java EE strategy, and an even more rigorous validation is required to certify an implementation. This environment enables portable server-side applications, such as Web services, servlets, and Enterprise JavaBeans, as well as with embedded systems based on OSGi, using Embedded Java environments. Through the new GlassFish project, Sun is working to create a fully functional, unified open-source implementation of the Java EE technologies.

Sun also distributes a superset of the JRE called the Java 2 SDK (more commonly known as the JDK), which includes development tools such as the Java compiler, Javadoc, Jar and debugger.

[JAVA] What is Java Programming Language?

Java is a programming language originally developed by James Gosling at Sun Microsystems and released in 1995 as a core component of Sun Microsystems' Java platform. The language derives much of its syntax from C and C++ but has a simpler object model and fewer low-level facilities. Java applications are typically compiled to bytecode that can run on any Java virtual machine (JVM) regardless of computer architecture.

There were five primary goals in the creation of the Java programming language
1. It should be "simple, object oriented, and familiar".
2. It should be "robust and secure".
3. It should be "architecture neutral and portable".
4. It should execute with "high performance".
5. It should be "interpreted, threaded, and dynamic".

[STRUKTUR DATA] Tree/Pohon dalam Bahasa Java

Download PDF Version : Struktur Data Tree/Pohon dalam Bahasa Java

Tree merupakan salah satu bentuk struktur data bukan linier yang menggambarkan bentuk hierarki antara elemen-elemen. Tree biasanya terdiri dari root (akar) dan node-node (simpul-simpul) yang berada di bawah root. Struktur seperti tree sangat banyak sekali dgunakan dalam dunia nyata, misalnya: struktur organisasi suatu perusahaan, pengaturan filesystem, daftar isi sebuah buku, dan masih banyak lagi.

Ilustrasi struktur data tree:

Degree (derajat) adalah jumlah edge yang keluar dan masuk dari sebuah node.
Contoh : node E memiliki in degree 1 dan out degree 2
Root (akar) adalah node yang memiliki derajat keluar >=0 dan derajat masuk = 0.
Contoh : node A adalah root
Subtree / child adalah bagian salah satu node dibawah root sampai ke bawah.
Contoh : tree C adalah right subtree dari A dan tree B merupakan left subtree dari A
node G dan F merupakan child dari node C
node F merupakan parent dari node J dan K
Ancestor adalah Node yang berada di atas node lain.
Contoh : node B adalah ancestor dari node E
Descendant adalah node yang berada di bawah node lain.
Contoh : node E adalah descendant dari node A.
Leaf (daun) adalah semua node yang derajat masuknya 1 dan derajat keluarnya 0.
Contoh : node D, H, I, J, K, dan G adalah leaf
Sibling adalah node yang mempunyai level yang sama dan parent yang sama.
Contoh : node D adalah sibling dari node A
Height (ketinggian) adalah level tertinggi dari tree ditambah 1.
Contoh : height dari tree A adalah 3 + 1 = 4
Weight (bobot) adalah jumlah leaf(daun) pada tree.
Contoh : weight dari tree A adalah 6

BINARY TREE
Sebuah tree dengan syarat bahwa tiap node hanya boleh memiliki maksimal 2 subtree yang disebut sebagai subpohon kiri(left subtree) dan subpohon kanan (right subtree) dan kedua subtree tersebut harus terpisah, atau dengan kata lain tiap node dalam binary tree hanya boleh memiliki paling banyak 2 child.

Binary tree terdiri dari :

1. Full Binary Tree : semua node (kecuali leaf pasti memiliki 2 anak dan tiap subtree memiliki panjang path yang sama)
   
   
   


2. Complete Binary Tree : mirip dengan full binary tree, tetapi tiap subtree boleh memiliki panjang path yang berbeda dan tiap node (kecuali leaf memiliki 2 anak)
   
   
   


3. Skewed Binary Tree : binary tree yang semua nodenya (kecuali leaf) hanya memiliki satu anak
   
   
   

BINARY SEARCH TREE
Binary tree dengan sifat bahwa nilai dari semua left child harus lebih kecil daripada nilai dari right child dan parentnya.
Contoh :

Contoh Implementasi Binary Search Tree :

/**
* Program membuat binary tree yang memiliki 2 anak dimana insertion
* dilakukan secara terurut, dimana data yang lebih kecil diletakkan di kiri
* dan yang lebih besar diletakkan di kanan.
* @author : Jeffrey Hermanto Halimsetiawan
* Selasa, 1 April 2008
**/

import java.util.*;

class Node{
 int data;
 Node left;
 Node right;
 Node(int x){
  this.data = x;
 }
}

public class BinTree{
 private Node root;

 /**
  * Mengecek apakah tree masih kosong
  **/
 private boolean isEmpty(){
  return (root == null);
 }
 /**
  * Memasukkan suatu nilai ke dalam tree.
  * Jika nilai tersebut lebih kecil dari nilai node, maka bergerak ke kiri terus
  * hingga menjadi child, begitu juga sebaliknya.
  **/
 public void insert(int input){
  Node temp = new Node(input);
  if (isEmpty())
   root = temp;
  else {
   Node cursor = root,
     parent = null;
   while (cursor != null){
    parent = cursor;
    if (input < cursor.data)
     cursor = cursor.left;
    else
     cursor = cursor.right;
   }
   /**
    * Menambahkan Node baru pada kiri/kanan Node parent bergantung
    * pada nilai input dan nilai yang disimpan Node parent
    **/
   if (input < parent.data){
    parent.left = temp;
    return;
   }
   else {
    parent.right = temp;
    return;
   }
  }
 }
 /**
  * Mencari suatu nilai dalam tree berdasarkan prinsip :
  * Selama belum menemukan nilai yang sama,
  * Jika nilai yang dicari lebih kecil dari nilai yang disimpan dalam Node
  * maka bergerak ke left Child begitu juga sebaliknya.
  **/
 public Node find(int key){
  Node cursor = root;
  while (cursor != null){
   if (cursor.data == key)
    return cursor;
   else if (key < cursor.data)
    cursor = cursor.left;
   else
    cursor = cursor.right;
  }
  return null;
 }
 public boolean delete(int key){
  Node cursor = root,
    parent = null;
  boolean found = false,
       isLeftChild = true; //menandai apakah Node yang dihapus merupakan left child
  if (!isEmpty()){
   while (cursor != null){
    parent = cursor;
    if (key == cursor.data){
     found = true;
     break;
    }
    else if (key < cursor.data){
     isLeftChild = true;
     cursor = cursor.left;
    }
    else {
     isLeftChild = false;
     cursor = cursor.right;
    }
   }
   if (!found)
    return false;
   else {

    /**
     * Untuk menghapus leaf (tidak punya child)
     **/
    if (cursor.left == null && cursor.right == null){
     if (cursor == root)
      root = null;
     else if (isLeftChild)
      parent.left = null;
     else
      parent.right = null;
    }
    /**
     * Jika node yang akan dihapus hanya memiliki salah satu subtree
     * maka tinggal memindahkan subtree menggantikan node yang dihapus
     **/
    else if (cursor.left == null){
     if (cursor == root)
      root = cursor.right;
     else if (isLeftChild)
      parent.left = cursor.right;
     else
      parent.right = cursor.right;
    }
    else if (cursor.right == null){
     if (cursor == root)
      root = cursor.left;
     else if (isLeftChild)
      parent.left = cursor.left;
     else
      parent.right = cursor.left;
    }

    /**
     * Jika node yang akan dihapus memiliki 2 child, maka cari successornya
     * dengan fungsi getSuccessor kemudian hubungkan subtree bagian kanan
     * dari node yang dihapus dengan successor
     **/
    else {
     Node successor = getSuccessor(cursor);
     if (cursor == root)
      root = successor;
     else if (isLeftChild)
      parent.left = successor;
     else
      parent.right = successor;
     //menyambung successor dengan cursor.right
     successor.right = cursor.right;
    }
   }
  }
  return true;
 }
 /**
  * Mencari nilai terbesar yang mendekati nilai yang disimpan Node
  * yang dihapus, Ilustrasi :
  *
  *     65
  *   59    72
  *  32  64
  *    62
  * misal : nilai yang dihapus 65, maka nilai terbesar yang mendekati adalah 64.
  * maka ambil 64 sebagai successor, kemudian gabungkan
  *    59
  *   32  63
  * Kemudian satukan keduanya :
  *      64
  *    59
  *   32  63
  * Jadilah urutan tree yang masih memenuhi syarat Binary Search Tree
  **/
 private Node getSuccessor(Node localNode){
  Node parent = null,
     successor = localNode,
     cursor = localNode.left;
  while (cursor != null){
   parent = successor;
   successor = cursor;
   cursor = cursor.right;
  }
  if (successor != localNode.left){
   parent.right = successor.left;
   successor.left = localNode.left;
  }
  return successor;
 }
 /**
  * Method traverse untuk mengelilingi Node-Node dalam tree
  **/
 public void traverse(int tipe){
  switch (tipe){
   case 1:
    System.out.print("\nPreorder traversal:\n");
               preOrder(root);
               break;
         case 2:
          System.out.print("\nInorder traversal:\n");
               inOrder(root);
               break;
         case 3:
          System.out.print("\nPostorder traversal:\n");
               postOrder(root);
               break;
  }
  System.out.println('\n');
 }
 private void preOrder(Node localRoot){
  if (localRoot == null) return;
  System.out.print(localRoot.data+" ");
  preOrder(localRoot.left);
  preOrder(localRoot.right);
 }
 private void inOrder(Node localRoot){
  if (localRoot == null) return;
  inOrder(localRoot.left);
  System.out.print(localRoot.data+" ");
  inOrder(localRoot.right);
 }
 private void postOrder(Node localRoot){
  if (localRoot == null) return;
  postOrder(localRoot.left);
  postOrder(localRoot.right);
  System.out.print(localRoot.data+" ");
 }

}

[Database] Access Database (mdb) and Java Connectivity

Mungkin banyak yang masih bingung (termasuk saya), cara untuk mengkoneksikan database access (.mdb) dengan Java. Nah di sini, saya akan mencoba untuk mengulas langkah-langkahnya.

1. Buat database Access dengan format .mdb, misalnya : hospital.mdb
   Misalnya, dalam hospital.mdb terdapat tabel Dokter terdapat field-field sebagai berikut :
   ID Nama Alamat Telp Golongan_ID Spesialisasi_ID ShiftKerja_ID


2. Membuat ODBC
   ODBC merupakan aturan yang digunakan untuk mengakses sebuah database. Caranya :
   ~ Start - Control Panel - Administrative Tools - Data Sources(ODBC)
   
   
   
   ~ Pilih tab User DSN - Add
   ~ Pilih Select
   
   
   
   ~ Pilih OK
   ~ Isi textbox Database Source Name, misalnya hospital
   
   
   
   ~ Klik Advanced, kemudian isi textbox Login Name dan Password misalnya: Login Name --> admin dan Password --> admin
   
   
   
   ~ Klik OK
   ~ Kemudian klik OK lagi, dan pada User Data Sources akan muncul 'hospital'


3. Membuat codingan javanya
   Contohnya seperti ini:
   

   import java.sql.Connection;
   import java.sql.DriverManager;
   import java.sql.ResultSet;
   import java.sql.Statement;
   
   /**
   *
   * @author Jeffrey
   */
   public class Main {
     private class tes{
   
     }
     /**
      * @param args the command line arguments
      */
     public static void main(String[] args) {
         // TODO code application logic here
         try {
             Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
             String cs = "jdbc:odbc:hospital;uid='admin';pw='admin";
             Connection cn = DriverManager.getConnection(cs);
             String qry = "SELECT * FROM Dokter";
             Statement stm = cn.createStatement();
             ResultSet rs = stm.executeQuery(qry);
             while(rs.next()) {
                 System.out.println("ID : "+rs.getString("ID"));
                 System.out.println("Nama : "+rs.getString("Nama"));
                 System.out.println("Alamat : "+rs.getString("Alamat"));
             }
             cn.close();
        } catch (Exception ex) {
            ex.printStackTrace();
        }
     }
   
   }

   
   

Ya, program diatas akan menampilkan query : "SELECT * FROM Dokter", yaitu: mengambil semua record pada tabel Dokter. Kemudian,

           while(rs.next()) {
              System.out.println("ID : "+rs.getString("ID"));
              System.out.println("Nama : "+rs.getString("Nama"));
              System.out.println("Alamat : "+rs.getString("Alamat"));
          }

hanya akan menampilkan field ID, Nama dan Alamat dari record-record pada tabel Dokter.