□ "CompositeMain.java"

 package com.maruno.composite.sample;
 public class CompositeMain {
     public static void main(String[] args) {
         try {
             System.out.println("資格 SJC-P");
             Certifying sjcp = new Certifying("SJC-P");
             sjcp.add(new Subject("SJC-P 035", 24000));
             sjcp.printList();
             System.out.println("");
 
             System.out.println("資格 SJC-WC");
             Certifying sjcwc = new Certifying("SJC-WC");
             sjcwc.add(sjcp);
             sjcwc.add(new Subject("SJC-WC 081", 24000));
             sjcwc.printList();
             System.out.println("");
 
             System.out.println("資格 Oracle Silver");
             Certifying oraclesilver = new Certifying("Oracle Silver");
             oraclesilver.add(new Subject("SQL 入門", 15000));
             oraclesilver.add(new Subject("Oracle 入門", 15000));
             oraclesilver.printList();
             System.out.println("");
 
             System.out.println("資格 Oracle Gold");
             Certifying oraclegold = new Certifying("Oracle Gold");
             oraclegold.add(oraclesilver);
             oraclegold.add(new Subject("DBA", 15000));
             oraclegold.add(new Subject("PL/SQL", 15000));
             oraclegold.printList();
 
         } catch (RuntimeException e) {
             e.printStackTrace();
         }
     }
 }

□ "Entry.java"

 package com.maruno.composite.sample;
 
 public abstract class Entry {
 
     public abstract String getName();                  // 名前を得る
     public abstract int getExamPrice();                // 受験価格を得る
 
     public Entry add(Entry entry)                      // エントリを追加する
                      throws RuntimeException {
         throw new RuntimeException();
     }
 
     public void printList() {                          // 一覧を表示する
         printList("");
     }
 
     protected abstract void printList(String prefix);  // prefixを前につけて一覧を表示する
 
     public String toString() {                         // 文字列表現
         return getName() + " (" + getExamPrice() + ")";
     }
 }

□ "Certifying.java"

 package com.maruno.composite.sample;
 
 import java.util.*;
 
 public class Certifying extends Entry {
     private String name; // 資格の名前
     private List certifying = new ArrayList(); // 資格エントリの集合
 
     public Certifying(String name) { // コンストラクター
         this.name = name;
     }
 
     public String getName() { // 名前を得る
         return name;
     }
 
     public int getExamPrice() { // サイズを得る
         int examPrice = 0;
         Iterator it = certifying.iterator();
         while (it.hasNext()) {
             Entry entry = (Entry) it.next();
             examPrice += entry.getExamPrice();
         }
         return examPrice;
     }
 
     public Entry add(Entry entry) { // エントリの追加
         certifying.add(entry);
         return this;
     }
 
     protected void printList(String prefix) { // エントリの一覧
         System.out.println(prefix + " - [" + this + "]");
         Iterator it = certifying.iterator();
         while (it.hasNext()) {
             Entry entry = (Entry) it.next();
             entry.printList(prefix + " - [" + name + "]");
         }
     }
 }

□ "Subject.java"

 package com.maruno.composite.sample;
 
 public class Subject extends Entry {
     private String name;
     private int examPrice;
 
     public Subject(String name, int examPrice) {
         this.name = name;
         this.examPrice = examPrice;
     }
 
     public String getName() {
         return name;
     }
 
     public int getExamPrice() {
         return examPrice;
     }
 
     protected void printList(String prefix) {
         System.out.println(prefix + " - \"" + this + "\"");
     }
 }

□ 実行結果

$ java -cp . com.maruno.composite.sample.CompositeMain
資格 SJC-P
 - [SJC-P (24000)]
 - [SJC-P] - "SJC-P 035 (24000)"

資格 SJC-WC
 - [SJC-WC (48000)]
 - [SJC-WC] - [SJC-P (24000)]
 - [SJC-WC] - [SJC-P] - "SJC-P 035 (24000)"
 - [SJC-WC] - "SJC-WC 081 (24000)"

資格 Oracle Silver
 - [Oracle Silver (30000)]
 - [Oracle Silver] - "SQL 入門 (15000)"
 - [Oracle Silver] - "Oracle 入門 (15000)"

資格 Oracle Gold
 - [Oracle Gold (60000)]
 - [Oracle Gold] - [Oracle Silver (30000)]
 - [Oracle Gold] - [Oracle Silver] - "SQL 入門 (15000)"
 - [Oracle Gold] - [Oracle Silver] - "Oracle 入門 (15000)"
 - [Oracle Gold] - "DBA (15000)"
 - [Oracle Gold] - "PL/SQL (15000)"

 Collection c;
     ...
 Iterator itr = c.iterator();
 while (itr.hasNext()) {
     itr.next();
 }

• Iteratorインターフェースを利用して文字列の昇順に出力する。

 import java.util.*;
 
 public class Set012 {
     public static void main(String[] args) {
         Set ts = new TreeSet();
         for (int i = 0; i < args.length; i++) {
             ts.add(args[i]);
         }
 
         Iterator itr = ts.iterator(); // イテレーターの宣言と生成
         while (itr.hasNext()) {
             System.out.println(itr.next());
         }
     }
 }

□ 実行結果

$ java Set012 Hello Java World
Hello
Java
World

 import java.awt.*;
 import java.awt.event.*;
 
 // Command パターン
 // デザイン･パターンを使わないソース
 public class Main01 extends Frame {
 
     Menu mnuFile;
 
     MenuItem mnuOpen, mnuExit;
 
     Button btnRed;
 
     Panel p;
 
     Frame fr;
 
     public Main01() {
         super("Frame without commands");
         fr = this; //save copy of this frame
         MenuBar mbar = new MenuBar();
         setMenuBar(mbar);
         mnuFile = new Menu("File", true);
         mbar.add(mnuFile);
         mnuOpen = new MenuItem("Open...");
         mnuFile.add(mnuOpen);
         mnuExit = new MenuItem("Exit");
         mnuFile.add(mnuExit);
         mnuOpen.addActionListener(new FileOpen());
         mnuExit.addActionListener(new FileExit());
         btnRed = new Button("Red");
         p = new Panel();
         add(p);
         p.add(btnRed);
         btnRed.addActionListener(new BtnRed());
         setBounds(100, 100, 200, 100);
         setVisible(true);
     }
 
     private void exitClicked() {
         System.exit(0);
     }
 
     public static void main(String[] args) {
         new Main01();
     }
 
     //　inner classes
 
     class FileOpen implements ActionListener {
         public void actionPerformed(ActionEvent e) {
             FileDialog fDlg =
                 new FileDialog(fr, "Open a file", FileDialog.LOAD);
             fDlg.show();
         }
     }
 
     class BtnRed implements ActionListener {
         public void actionPerformed(ActionEvent e) {
             p.setBackground(Color.red);
         }
     }
 
     class FileExit implements ActionListener {
         public void actionPerformed(ActionEvent e) {
             System.exit(0);
         }
     }
 }

 import java.awt.*;
 import java.awt.event.*;
 
 //Command パターン
 //デザイン･パターンを使うソース
 public class Main02 extends Frame implements ActionListener {
     Menu mnuFile;
 
     FileOpenCommand mnuOpen;
 
     FileExitCommand mnuExit;
 
     RedButtonCommand btnRed;
 
     Panel p;
 
     public Main02() {
         super("Frame with external commands");
         MenuBar mbar = new MenuBar();
         setMenuBar(mbar);
 
         mnuFile = new Menu("File", true);
         mbar.add(mnuFile);
 
         mnuOpen = new FileOpenCommand("Open...", this);
         mnuFile.add(mnuOpen);
         mnuExit = new FileExitCommand("Exit");
         mnuFile.add(mnuExit);
 
         mnuOpen.addActionListener(this);
         mnuExit.addActionListener(this);
 
         p = new Panel();
         add(p);
         btnRed = new RedButtonCommand("Red", p);
 
         p.add(btnRed);
 
         btnRed.addActionListener(this);
         setBounds(100, 100, 200, 100);
         setVisible(true);
     }
 
     public void actionPerformed(ActionEvent e) {
         Command obj = (Command) e.getSource();
         obj.execute();
     }
 
     public static void main(String[] args) {
         new Main02();
     }
 }

 interface Command {
     void execute();
 }

 import java.awt.*;
 
 public class FileExitCommand extends MenuItem implements Command {
     public FileExitCommand(String caption) {
         super(caption);
     }
 
     public void execute() {
         System.exit(0);    
     }                      
 }

 import java.awt.*;
 
 public class FileOpenCommand extends MenuItem implements Command {
     Frame frame;
 
     public FileOpenCommand(String caption, Frame frame) {
         super(caption);
         this.frame = frame;
     }
 
     public void execute() {                       
         new FileDialog(frame, "Open file").show();
     }                                             
 }

 import java.awt.*;
 
 public class RedButtonCommand extends Button implements Command {
     Panel p;
 
     public RedButtonCommand(String caption, Panel p) {
         super(caption);
         this.p = p;
     }
 
     public void execute() {        
         p.setBackground(Color.RED);
     }                              
 }

 import java.awt.*;
 import java.awt.event.*;
 
 //Command パターン
 public class Main22
     extends Frame
     implements ActionListener, MouseMotionListener, WindowListener {
     // 描画履歴
     private MacroCommand history = new MacroCommand();
 
     // 描画領域
     private DrawCanvas canvas = new DrawCanvas(400, 400, history);
 
     // 消去ボタン
     private Button clearButton = new Button("clear");
 
     // コンストラクタ
     public Main22(String title) {
         super(title);
 
         this.addWindowListener(this);
         canvas.addMouseMotionListener(this);
         clearButton.addActionListener(this);
 
         Panel buttonPanel = new Panel();
         buttonPanel.add(clearButton);
         Panel mainPanel = new Panel();
         mainPanel.add(buttonPanel);
         mainPanel.add(canvas);
         this.add(buttonPanel, BorderLayout.NORTH);
         this.add(mainPanel, BorderLayout.SOUTH);
         pack();
         setVisible(true);
     }
 
     // ActionListener用
     public void actionPerformed(ActionEvent e) {
         if (e.getSource() == clearButton) {
             history.clear();
             canvas.repaint();
         }
     }
 
     // MouseMotionListener用
     public void mouseMoved(MouseEvent e) {
     }
 
     public void mouseDragged(MouseEvent e) {
         Command cmd = new DrawCommand(canvas, e.getPoint());
         history.append(cmd);                                
         cmd.execute();                                      
     }
 
     // WindowListener用
     public void windowClosing(WindowEvent e) {
         System.exit(0);
     }
 
     public void windowActivated(WindowEvent e) {
     }
 
     public void windowClosed(WindowEvent e) {
     }
 
     public void windowDeactivated(WindowEvent e) {
     }
 
     public void windowDeiconified(WindowEvent e) {
     }
 
     public void windowIconified(WindowEvent e) {
     }
 
     public void windowOpened(WindowEvent e) {
     }
 
     public static void main(String[] args) {
         new Main22("Command Pattern Sample");
     }
 }

 interface Command {
     void execute();
 }

 import java.util.Stack;
 import java.util.Iterator;
 
 public class MacroCommand implements Command {
     // 命令の集合
     private Stack commands = new Stack();
     // 実行
     public void execute() {                
         Iterator it = commands.iterator(); 
         while (it.hasNext()) {             
             ((Command)it.next()).execute();
         }                                  
     }                                      
     // 追加
     public void append(Command cmd) {
         if (cmd != this) {
             commands.push(cmd);
         }
     }
     // 最後の命令を削除
     public void undo() {
         if (!commands.empty()) {
             commands.pop();
         }
     }
     // 全部削除
     public void clear() {
         commands.clear();
     }
 }

 interface Drawable {
     void draw(int x, int y);
 }

 import java.awt.Point;
 
 public class DrawCommand implements Command {
     // 描画対象
     protected Drawable drawable;
 
     // 描画位置
     private Point position;
 
     // コンストラクタ
     public DrawCommand(Drawable drawable, Point position) {
         this.drawable = drawable;
         this.position = position;
     }
 
     // 実行
     public void execute() {                   
         drawable.draw(position.x, position.y);
     }                                         
 }

 import java.awt.*;
 
 public class DrawCanvas extends Canvas implements Drawable {
     // 描画色
     private Color color = Color.red;
 
     // 描画する点の半径
     private int radius = 6;
 
     // 履歴
     private MacroCommand history;
 
     // コンストラクタ
     public DrawCanvas(int width, int height, MacroCommand history) {
         setSize(width, height);
         setBackground(Color.white);
         this.history = history;
     }
 
     // 履歴全体を再描画
     public void paint(Graphics g) {
         history.execute();
     }
 
     // 描画
     public void draw(int x, int y) {
         Graphics g = getGraphics();
         g.setColor(color);
         g.fillOval(x - radius, y - radius, radius * 2, radius * 2);
     }
 }