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/Listing2001.java                 | 76 ++++++++++++++++++++++
 1 file changed, 76 insertions(+)
 create mode 100644 Master/Reference Architectures and Patterns/hjp5/examples/Listing2001.java

(limited to 'Master/Reference Architectures and Patterns/hjp5/examples/Listing2001.java')

diff --git a/Master/Reference Architectures and Patterns/hjp5/examples/Listing2001.java b/Master/Reference Architectures and Patterns/hjp5/examples/Listing2001.java
new file mode 100644
index 0000000..14ae58a
--- /dev/null
+++ b/Master/Reference Architectures and Patterns/hjp5/examples/Listing2001.java	
@@ -0,0 +1,76 @@
+/* Listing2001.java */
+
+import java.io.*;
+
+class ClassFileReader
+{
+  private RandomAccessFile f;
+
+  public ClassFileReader(String name)
+  throws IOException
+  {
+    if (!name.endsWith(".class")) {
+      name += ".class";
+    }
+    f = new RandomAccessFile(name,"r");
+  }
+
+  public void close()
+  {
+    if (f != null) {
+      try {
+        f.close();
+      } catch (IOException e) {
+        //nichts
+      }
+    }
+  }
+
+  public void printSignature()
+  throws IOException
+  {
+    String ret = "";
+    int b;
+
+    f.seek(0);
+    for (int i=0; i<4; ++i) {
+      b = f.read();
+      ret += (char)(b/16+'A'-10);
+      ret += (char)(b%16+'A'-10);
+    }
+    System.out.println(
+      "Signatur...... "+
+      ret
+    );
+  }
+
+  public void printVersion()
+  throws IOException
+  {
+    int minor, major;
+
+    f.seek(4);
+    minor = f.readShort();
+    major = f.readShort();
+    System.out.println(
+      "Version....... "+
+      major+"."+minor
+    );
+  }
+}
+
+public class Listing2001
+{
+  public static void main(String[] args)
+  {
+    ClassFileReader f;
+
+    try {
+      f = new ClassFileReader("Listing2001");
+      f.printSignature();
+      f.printVersion();
+    } catch (IOException e) {
+      System.out.println(e.toString());
+    }
+  }
+}
\ No newline at end of file
-- 
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