From 33613a85afc4b1481367fbe92a17ee59c240250b Mon Sep 17 00:00:00 2001
From: Sven Eisenhauer <sven@sven-eisenhauer.net>
Date: Fri, 10 Nov 2023 15:11:48 +0100
Subject: add new repo

---
 .../hjp5/examples/Listing1018.java                 | 106 +++++++++++++++++++++
 1 file changed, 106 insertions(+)
 create mode 100644 Master/Reference Architectures and Patterns/hjp5/examples/Listing1018.java

(limited to 'Master/Reference Architectures and Patterns/hjp5/examples/Listing1018.java')

diff --git a/Master/Reference Architectures and Patterns/hjp5/examples/Listing1018.java b/Master/Reference Architectures and Patterns/hjp5/examples/Listing1018.java
new file mode 100644
index 0000000..8613621
--- /dev/null
+++ b/Master/Reference Architectures and Patterns/hjp5/examples/Listing1018.java	
@@ -0,0 +1,106 @@
+/* Listing1018.java */
+
+interface MenuVisitor
+{
+  abstract void visitMenuEntry(MenuEntry2 entry);
+  abstract void visitMenuStarted(Menu2 menu);
+  abstract void visitMenuEnded(Menu2 menu);
+}
+
+class MenuEntry2
+{
+  protected String name;
+
+  public MenuEntry2(String name)
+  {
+    this.name = name;
+  }
+
+  public String toString()
+  {
+    return name;
+  }
+
+  public void accept(MenuVisitor visitor)
+  {
+    visitor.visitMenuEntry(this);
+  }
+}
+
+class Menu2
+extends MenuEntry2
+{
+  MenuEntry2[] entries;
+  int         entryCnt;
+
+  public Menu2(String name, int maxElements)
+  {
+    super(name);
+    this.entries = new MenuEntry2[maxElements];
+    entryCnt = 0;
+  }
+
+  public void add(MenuEntry2 entry)
+  {
+    entries[entryCnt++] = entry;
+  }
+
+  public String toString()
+  {
+    String ret = "(";
+    for (int i = 0; i < entryCnt; ++i) {
+      ret += (i != 0 ? "," : "") + entries[i].toString();
+    }
+    return ret + ")";
+  }
+
+  public void accept(MenuVisitor visitor)
+  {
+    visitor.visitMenuStarted(this);
+    for (int i = 0; i < entryCnt; ++i) {
+      entries[i].accept(visitor);
+    }
+    visitor.visitMenuEnded(this);
+  }
+}
+
+class MenuPrintVisitor
+implements MenuVisitor
+{
+  String indent = "";
+
+  public void visitMenuEntry(MenuEntry2 entry)
+  {
+    System.out.println(indent + entry.name);
+  }
+
+  public void visitMenuStarted(Menu2 menu)
+  {
+    System.out.println(indent + menu.name);
+    indent += " ";
+  }
+
+  public void visitMenuEnded(Menu2 menu)
+  {
+    indent = indent.substring(1);
+  }
+}
+
+public class Listing1018
+{
+  public static void main(String[] args)
+  {
+    Menu2 filemenu = new Menu2("Datei", 5);
+    filemenu.add(new MenuEntry2("Neu"));
+    filemenu.add(new MenuEntry2("Laden"));
+    filemenu.add(new MenuEntry2("Speichern"));
+    Menu2 confmenu = new Menu2("Konfiguration", 3);
+    confmenu.add(new MenuEntry2("Farben"));
+    confmenu.add(new MenuEntry2("Fenster"));
+    confmenu.add(new MenuEntry2("Pfade"));
+    filemenu.add(confmenu);
+    filemenu.add(new MenuEntry2("Beenden"));
+
+    filemenu.accept(new MenuPrintVisitor());
+  }
+}
\ No newline at end of file
-- 
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