Java

Ví dụ sau minh hoạ ví dụ nêu ở trên với kết quả là:

(Europe:  (England: London)   (France: Paris))

import java.util.*;interface Component {   public String defaultMethod();   public ArrayList<Component> getChildren();   public boolean addComponent(Component c);   public boolean removeComponent(Component c);}class Composite implements Component {   private String id;   private ArrayList<Component> components = new ArrayList<Component>();   public Composite(String identification)         { id = identification; }   public String defaultMethod() {        String s = " (" + id + ":";        for (Component child: getChildren())           s += " " + child.defaultMethod();       return s + ") ";   }   public ArrayList<Component> getChildren()       { return components; }   public boolean addComponent(Component c)        { return components.add(c); }   public boolean removeComponent(Component c)     { return components.remove(c); }}   class Leaf implements Component {   private String id;   public Leaf(String identification)              { id = identification; }   public String defaultMethod()                   { return id; }   public ArrayList<Component> getChildren()       { return null; }   public boolean addComponent(Component c)        { return false; }   public boolean removeComponent(Component c)     { return false; }}class CompositePattern {   public static void main(String[] args) {       Composite england = new Composite("England");       Leaf york = new Leaf("York");       Leaf london = new Leaf("London");       england.addComponent(york);       england.addComponent(london);       england.removeComponent(york);       Composite france = new Composite("France");       france.addComponent(new Leaf("Paris"));       Composite europe = new Composite("Europe");       europe.addComponent(england);       europe.addComponent(france);               System.out.println(europe.defaultMethod());     }}