JavaTXCompilerInJavaTX/de/dhbwstuttgart/bytecode/Test.java

package de.dhbwstuttgart.bytecode;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.lang.invoke.CallSite;
import java.lang.invoke.MethodHandle;
import java.lang.invoke.MethodHandles;
import java.lang.invoke.MethodType;
import java.lang.reflect.Method;
import java.net.URL;
import java.net.URLClassLoader;

import org.objectweb.asm.ClassReader;
import org.objectweb.asm.ClassWriter;
import org.objectweb.asm.Handle;
import org.objectweb.asm.Label;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;
import org.objectweb.asm.Type;

import javassist.runtime.Desc;

public class Test {
	private static final String rootDirectory = System.getProperty("user.dir") + "/bin/de/dhbwstuttgart/bytecode/";

	protected static ClassLoader getClassLoader() throws Exception {
		File file = new File(rootDirectory);
		URL url = file.toURI().toURL();
		URL[] urls = new URL[] { url };
		System.out.println(urls[0]);
		return new URLClassLoader(urls);
	}

	public static void main(String[] args) {
		// Test Lambda
		ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS);
		cw.visit(Opcodes.V1_8, Opcodes.ACC_PUBLIC + Opcodes.ACC_SUPER, "TestClass", null, "java/lang/Object", null);

		cw.visitSource("TestClass.java", null);

		// Create Constructor
		MethodVisitor mv = cw.visitMethod(Opcodes.ACC_PUBLIC, "<init>", "()V", null, null);
		mv.visitVarInsn(Opcodes.ALOAD, 0);

		mv.visitMethodInsn(Opcodes.INVOKESPECIAL, "java/lang/Object", "<init>", "()V");

		// mv.visitMethodInsn(INVOKEDYNAMIC, "#0", "run", "()Ljava/lang/Runnable");
		//Call site, which, when invoked, returns an instance of the functional interface to which
		//the lambda is being converted
		MethodType mt = MethodType.methodType(CallSite.class, MethodHandles.Lookup.class, String.class,
				MethodType.class, MethodType.class, MethodHandle.class, MethodType.class);
		
		Handle bootstrap = new Handle(Opcodes.H_INVOKESTATIC, "java/lang/invoke/LambdaMetafactory", "metafactory",
				mt.toMethodDescriptorString());
		Handle arg2 = new Handle(Opcodes.H_INVOKESTATIC, "TestClass", "lambda$0", "()V");

		mv.visitInvokeDynamicInsn("run", "()Ljava/lang/Runnable;", bootstrap, 
				Type.getMethodType("()V"), arg2,
				Type.getMethodType("()V"));

		mv.visitVarInsn(Opcodes.ASTORE, 1);
		mv.visitVarInsn(Opcodes.ALOAD, 1);
		mv.visitMethodInsn(Opcodes.INVOKEINTERFACE, "java/lang/Runnable", "run", "()V");
		mv.visitInsn(Opcodes.RETURN);
		
		// creates bridge method, contains lambdas body
				MethodVisitor mvl = cw.visitMethod(Opcodes.ACC_PRIVATE + Opcodes.ACC_STATIC + Opcodes.ACC_SYNTHETIC, "lambda$0",
						"()V", null, null);
				mvl.visitCode();
				mvl.visitFieldInsn(Opcodes.GETSTATIC, "java/lang/System", "out", "Ljava/io/PrintStream;");
				mvl.visitLdcInsn("lambda");
				mvl.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/io/PrintStream", "println", "(Ljava/lang/String;)V");
				mvl.visitInsn(Opcodes.RETURN);
				mvl.visitMaxs(2, 0);
				mvl.visitEnd();
		
		mv.visitMaxs(1, 2);
		mv.visitEnd();
		

		cw.visitInnerClass("java/lang/invoke/MethodHandles$Lookup", "java/lang/invoke/MethodHandles", "Lookup",
				Opcodes.ACC_PUBLIC + Opcodes.ACC_STATIC + Opcodes.ACC_FINAL);
		cw.visitEnd();

		byte[] b = cw.toByteArray();

		// Test if statement
		/*
		 * ClassWriter cw = new
		 * ClassWriter(ClassWriter.COMPUTE_FRAMES|ClassWriter.COMPUTE_MAXS);
		 * 
		 * cw.visit(Opcodes.V1_8, Opcodes.ACC_PUBLIC+Opcodes.ACC_SUPER, "TestIf", null,
		 * "java/lang/Object", null); MethodVisitor mv =
		 * cw.visitMethod(Opcodes.ACC_PUBLIC, "<init>", "(Ljava/lang/Boolean;)V", null,
		 * null); mv.visitCode();
		 * 
		 * // Label l0 = new Label(); // mv.visitLabel(l0);
		 * 
		 * mv.visitVarInsn(Opcodes.ALOAD, 0);
		 * 
		 * mv.visitMethodInsn(Opcodes.INVOKESPECIAL, "java/lang/Object", "<init>",
		 * "()V");
		 * 
		 * // Label l1 = new Label(); // mv.visitLabel(l1);
		 * mv.visitVarInsn(Opcodes.ALOAD, 1); mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL,
		 * "java/lang/Boolean", "booleanValue", "()Z");
		 * 
		 * Label label = new Label(); mv.visitJumpInsn(Opcodes.IFEQ, label);
		 * 
		 * mv.visitFieldInsn(Opcodes.GETSTATIC, "java/lang/System", "out",
		 * "Ljava/io/PrintStream;"); mv.visitLdcInsn("1");
		 * mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/io/PrintStream", "println",
		 * "(Ljava/lang/String;)V");
		 * 
		 * Label endLabel = new Label(); mv.visitJumpInsn(Opcodes.GOTO, endLabel);
		 * 
		 * mv.visitLabel(label); mv.visitFieldInsn(Opcodes.GETSTATIC,
		 * "java/lang/System", "out", "Ljava/io/PrintStream;"); mv.visitLdcInsn("0");
		 * mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/io/PrintStream", "println",
		 * "(Ljava/lang/String;)V");
		 * 
		 * 
		 * 
		 * mv.visitLabel(endLabel); mv.visitInsn(Opcodes.RETURN);
		 * 
		 * // Label l2 = new Label(); // mv.visitLabel(l2);
		 * 
		 * // mv.visitLocalVariable("this", "LTestIf;", null, l0, l2, 0); //
		 * mv.visitLocalVariable("b", "Ljava/lang/Boolean;", null, l0, l2, 1);
		 * mv.visitMaxs(2, 2); mv.visitEnd();
		 * 
		 * cw.visitEnd(); byte[] b = cw.toByteArray();
		 */
		FileOutputStream output;

		try {
			output = new FileOutputStream(new File(System.getProperty("user.dir") + "/testBytecode/TestClass.class"));
			output.write(b);
			output.close();
		} catch (FileNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}

	}
}