corejava第10版

corejava第10版/v2ch08/bytecodeAnnotations/EntryLoggingAgent.java

@@ -0,0 +1,26 @@
+package bytecodeAnnotations;
+
+import java.lang.instrument.*;
+
+import org.objectweb.asm.*;
+
+/**
+ * @version 1.10 2016-05-10
+ * @author Cay Horstmann
+ */
+public class EntryLoggingAgent
+{
+   public static void premain(final String arg, Instrumentation instr)
+   {
+      instr.addTransformer((loader, className, cl, pd, data) ->
+         {
+            if (!className.replace("/", ".").equals(arg)) return null;
+            ClassReader reader = new ClassReader(data);
+            ClassWriter writer = new ClassWriter(
+               ClassWriter.COMPUTE_MAXS | ClassWriter.COMPUTE_FRAMES);
+            EntryLogger el = new EntryLogger(writer, className);
+            reader.accept(el, ClassReader.EXPAND_FRAMES);
+            return writer.toByteArray();
+      });
+   }
+}