Java Code Examples for jdk.internal.org.objectweb.asm.MethodVisitor#visitEnd()

The following examples show how to use jdk.internal.org.objectweb.asm.MethodVisitor#visitEnd() . These examples are extracted from open source projects. You can vote up the ones you like or vote down the ones you don't like, and go to the original project or source file by following the links above each example. You may check out the related API usage on the sidebar.
Example 1
void addConstructor(BinderClassWriter cw) {
    MethodType constrType = MethodType.methodType(void.class, VarForm.class, boolean.class, long.class, long.class, long.class, long[].class);
    MethodVisitor mv = cw.visitMethod(0, "<init>", constrType.toMethodDescriptorString(), null, null);
    mv.visitCode();
    //super call
    mv.visitVarInsn(ALOAD, 0);
    mv.visitVarInsn(ALOAD, 1);
    mv.visitTypeInsn(CHECKCAST, Type.getInternalName(VarForm.class));
    mv.visitVarInsn(ILOAD, 2);
    mv.visitVarInsn(LLOAD, 3);
    mv.visitVarInsn(LLOAD, 5);
    mv.visitVarInsn(LLOAD, 7);
    mv.visitMethodInsn(INVOKESPECIAL, Type.getInternalName(BASE_CLASS), "<init>",
            MethodType.methodType(void.class, VarForm.class, boolean.class, long.class, long.class, long.class).toMethodDescriptorString(), false);
    //init dimensions
    for (int i = 0 ; i < dimensions ; i++) {
        mv.visitVarInsn(ALOAD, 0);
        mv.visitVarInsn(ALOAD, 9);
        mv.visitLdcInsn(i);
        mv.visitInsn(LALOAD);
        mv.visitFieldInsn(PUTFIELD, implClassName, "dim" + i, "J");
    }
    mv.visitInsn(RETURN);
    mv.visitMaxs(0, 0);
    mv.visitEnd();
}
 
Example 2
public static void writeClassFile() throws Exception {
    ClassWriter cw = new ClassWriter(0);
    MethodVisitor mv;

    cw.visit(99, ACC_PUBLIC + ACC_SUPER, "ClassFile", null, "java/lang/Object", null);
    mv = cw.visitMethod(ACC_PUBLIC, "<init>", "()V", null, null);
    mv.visitCode();
    mv.visitVarInsn(ALOAD, 0);
    mv.visitMethodInsn(INVOKESPECIAL, "java/lang/Object", "<init>", "()V", false);
    mv.visitInsn(RETURN);
    mv.visitMaxs(1, 1);
    mv.visitEnd();
    cw.visitEnd();

    try (FileOutputStream fos = new FileOutputStream(new File("ClassFile.class"))) {
         fos.write(cw.toByteArray());
    }
}
 
Example 3
/**
 * The bytes for D, a NOT abstract class extending abstract class C without
 * supplying an implementation for abstract method m. There is a default
 * method in the interface I, but it should lose to the abstract class.
 *
 * @return
 * @throws Exception
 */
public static byte[] bytesForD() throws Exception {

    ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_FRAMES
            | ClassWriter.COMPUTE_MAXS);
    MethodVisitor mv;

    cw.visit(V1_8, ACC_PUBLIC + ACC_SUPER, "p/D", null, "p/C", null);

    {
        mv = cw.visitMethod(ACC_PUBLIC, "<init>", "()V", null, null);
        mv.visitCode();
        mv.visitVarInsn(ALOAD, 0);
        mv.visitMethodInsn(INVOKESPECIAL, "p/C", "<init>", "()V");
        mv.visitInsn(RETURN);
        mv.visitMaxs(0, 0);
        mv.visitEnd();
    }
    cw.visitEnd();

    return cw.toByteArray();
}
 
Example 4
/**
 * The bytes for D, a NOT abstract class extending abstract class C without
 * supplying an implementation for abstract method m. There is a default
 * method in the interface I, but it should lose to the abstract class.
 *
 * @return
 * @throws Exception
 */
public static byte[] bytesForD() throws Exception {

    ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_FRAMES
            | ClassWriter.COMPUTE_MAXS);
    MethodVisitor mv;

    cw.visit(V1_8, ACC_PUBLIC + ACC_SUPER, "p/D", null, "p/C", null);

    {
        mv = cw.visitMethod(ACC_PUBLIC, "<init>", "()V", null, null);
        mv.visitCode();
        mv.visitVarInsn(ALOAD, 0);
        mv.visitMethodInsn(INVOKESPECIAL, "p/C", "<init>", "()V");
        mv.visitInsn(RETURN);
        mv.visitMaxs(0, 0);
        mv.visitEnd();
    }
    cw.visitEnd();

    return cw.toByteArray();
}
 
Example 5
/**
 * The bytes for D, a NOT abstract class extending abstract class C without
 * supplying an implementation for abstract method m. There is a default
 * method in the interface I, but it should lose to the abstract class.
 *
 * @return
 * @throws Exception
 */
public static byte[] bytesForD() throws Exception {

    ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_FRAMES
            | ClassWriter.COMPUTE_MAXS);
    MethodVisitor mv;

    cw.visit(V1_8, ACC_PUBLIC + ACC_SUPER, "p/D", null, "p/C", null);

    {
        mv = cw.visitMethod(ACC_PUBLIC, "<init>", "()V", null, null);
        mv.visitCode();
        mv.visitVarInsn(ALOAD, 0);
        mv.visitMethodInsn(INVOKESPECIAL, "p/C", "<init>", "()V");
        mv.visitInsn(RETURN);
        mv.visitMaxs(0, 0);
        mv.visitEnd();
    }
    cw.visitEnd();

    return cw.toByteArray();
}
 
Example 6
public static void writeClassFile() throws Exception {
    ClassWriter cw = new ClassWriter(0);
    MethodVisitor mv;

    cw.visit(99, ACC_PUBLIC + ACC_SUPER, "ClassFile", null, "java/lang/Object", null);
    mv = cw.visitMethod(ACC_PUBLIC, "<init>", "()V", null, null);
    mv.visitCode();
    mv.visitVarInsn(ALOAD, 0);
    mv.visitMethodInsn(INVOKESPECIAL, "java/lang/Object", "<init>", "()V", false);
    mv.visitInsn(RETURN);
    mv.visitMaxs(1, 1);
    mv.visitEnd();
    cw.visitEnd();

    try (FileOutputStream fos = new FileOutputStream(new File("ClassFile.class"))) {
         fos.write(cw.toByteArray());
    }
}
 
Example 7
private void buildConstructor() {
    MethodVisitor mv = classWriter.visitMethod(Opcodes.ACC_PRIVATE, METHOD_EVENT_HANDLER_CONSTRUCTOR.getName(), makeConstructorDescriptor(settingInfos), null, null);
    mv.visitVarInsn(Opcodes.ALOAD, 0); // this
    mv.visitVarInsn(Opcodes.ILOAD, 1); // registered
    mv.visitVarInsn(Opcodes.ALOAD, 2); // event type
    mv.visitVarInsn(Opcodes.ALOAD, 3); // event control
    mv.visitMethodInsn(Opcodes.INVOKESPECIAL, Type.getInternalName(EventHandler.class), METHOD_EVENT_HANDLER_CONSTRUCTOR.getName(), METHOD_EVENT_HANDLER_CONSTRUCTOR.getDescriptor(), false);
    for (SettingInfo si : settingInfos) {
        mv.visitVarInsn(Opcodes.ALOAD, 0); // this
        mv.visitVarInsn(Opcodes.ALOAD, si.index + 4); // Setting Control
        mv.visitFieldInsn(Opcodes.PUTFIELD, internalClassName, si.fieldName, TYPE_SETTING_CONTROL.getDescriptor());
    }
    // initialized string field writers
    int fieldIndex = 0;
    for (FieldInfo field : fields) {
        if (field.isString()) {
            mv.visitVarInsn(Opcodes.ALOAD, 0);
            mv.visitVarInsn(Opcodes.ALOAD, 0);
            mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, Type.getInternalName(EventHandler.class), "createStringFieldWriter", "()" + TYPE_STRING_POOL.getDescriptor(), false);
            mv.visitFieldInsn(Opcodes.PUTFIELD, internalClassName, FIELD_PREFIX_STRING_POOL + fieldIndex, TYPE_STRING_POOL.getDescriptor());
        }
        fieldIndex++;
    }
    mv.visitInsn(Opcodes.RETURN);
    mv.visitMaxs(0, 0);
    mv.visitEnd();
}
 
Example 8
/**
 * Generate bytecode for SystemModules::methodResoultions method
 */
private void genModuleResolutionsMethod() {
    MethodVisitor mresmv =
        cw.visitMethod(ACC_PUBLIC+ACC_STATIC,
                       "moduleResolutions",
                       "()" + MODULE_RESOLUTIONS_ARRAY_SIGNATURE,
                       "()" + MODULE_RESOLUTIONS_ARRAY_SIGNATURE,
                       null);
    mresmv.visitCode();
    pushInt(mresmv, moduleInfos.size());
    mresmv.visitTypeInsn(ANEWARRAY, MODULE_RESOLUTION_CLASSNAME);
    mresmv.visitVarInsn(ASTORE, 0);

    for (int index=0; index < moduleInfos.size(); index++) {
        ModuleInfo minfo = moduleInfos.get(index);
        if (minfo.moduleResolution() != null) {
            mresmv.visitVarInsn(ALOAD, 0);
            pushInt(mresmv, index);
            mresmv.visitTypeInsn(NEW, MODULE_RESOLUTION_CLASSNAME);
            mresmv.visitInsn(DUP);
            mresmv.visitLdcInsn(minfo.moduleResolution().value());
            mresmv.visitMethodInsn(INVOKESPECIAL,
                                   MODULE_RESOLUTION_CLASSNAME,
                                   "<init>",
                                   "(I)V", false);
            mresmv.visitInsn(AASTORE);
        }
    }
    mresmv.visitVarInsn(ALOAD, 0);
    mresmv.visitInsn(ARETURN);
    mresmv.visitMaxs(0, 0);
    mresmv.visitEnd();
}
 
Example 9
private void buildConstructor() {
    MethodVisitor mv = classWriter.visitMethod(Opcodes.ACC_PRIVATE, METHOD_EVENT_HANDLER_CONSTRUCTOR.getName(), makeConstructorDescriptor(settingInfos), null, null);
    mv.visitVarInsn(Opcodes.ALOAD, 0); // this
    mv.visitVarInsn(Opcodes.ILOAD, 1); // registered
    mv.visitVarInsn(Opcodes.ALOAD, 2); // event type
    mv.visitVarInsn(Opcodes.ALOAD, 3); // event control
    mv.visitMethodInsn(Opcodes.INVOKESPECIAL, Type.getInternalName(eventHandlerProxy), METHOD_EVENT_HANDLER_CONSTRUCTOR.getName(), METHOD_EVENT_HANDLER_CONSTRUCTOR.getDescriptor(), false);
    for (SettingInfo si : settingInfos) {
        mv.visitVarInsn(Opcodes.ALOAD, 0); // this
        mv.visitVarInsn(Opcodes.ALOAD, si.index + 4); // Setting Control
        mv.visitFieldInsn(Opcodes.PUTFIELD, internalClassName, si.fieldName, TYPE_SETTING_CONTROL.getDescriptor());
    }
    // initialized string field writers
    int fieldIndex = 0;
    for (FieldInfo field : fields) {
        if (field.isString()) {
            mv.visitVarInsn(Opcodes.ALOAD, 0);
            mv.visitVarInsn(Opcodes.ALOAD, 0);
            mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, Type.getInternalName(eventHandlerProxy), "createStringFieldWriter", "()" + TYPE_STRING_POOL.getDescriptor(), false);
            mv.visitFieldInsn(Opcodes.PUTFIELD, internalClassName, FIELD_PREFIX_STRING_POOL + fieldIndex, TYPE_STRING_POOL.getDescriptor());
        }
        fieldIndex++;
    }
    mv.visitInsn(Opcodes.RETURN);
    mv.visitMaxs(0, 0);
    mv.visitEnd();
}
 
Example 10
private byte[] loadClassData(String name) throws Exception {
  ClassWriter cw = new ClassWriter(0);
  MethodVisitor mv;

  if (name.equals("C")) {
    cw.visit(52, ACC_SUPER | ACC_PUBLIC, "C", null, "java/lang/Object", null);
    {
      mv = cw.visitMethod(ACC_PRIVATE | ACC_STATIC, "m", "()V", null, null);
      mv.visitCode();
      mv.visitInsn(RETURN);
      mv.visitMaxs(0, 1);
      mv.visitEnd();
    }
    cw.visitEnd();
    return cw.toByteArray();
  } else if (name.equals("Exec")) {
    cw.visit(52, ACC_SUPER | ACC_PUBLIC, "Exec", null, "java/lang/Object", null);
    {
      mv = cw.visitMethod(ACC_PUBLIC | ACC_STATIC, "invokeRef", "()V", null, null);
      mv.visitCode();
      Handle h = new Handle(H_INVOKESTATIC, "C", "m", "()V");
      mv.visitInvokeDynamicInsn("C", "()V", h);
      mv.visitInsn(RETURN);
      mv.visitMaxs(0, 0);
      mv.visitEnd();
    }
    cw.visitEnd();
    return cw.toByteArray();
  }
  return null;
}
 
Example 11
private static void buildDurationMethod() {
    MethodVisitor mv = classWriter.visitMethod(Opcodes.ACC_PUBLIC + Opcodes.ACC_STATIC, METHOD_DURATION.getName(), METHOD_DURATION.getDescriptor(), null, null);
    mv.visitCode();
    mv.visitVarInsn(Opcodes.LLOAD, 0);
    mv.visitMethodInsn(Opcodes.INVOKESTATIC, Type.getInternalName(EventHandler.class), METHOD_DURATION.getName(), METHOD_DURATION.getDescriptor(), false);
    mv.visitInsn(Opcodes.LRETURN);
    mv.visitMaxs(0, 0);
    mv.visitEnd();
}
 
Example 12
/**
 * Generate bytecode for SystemModules::targets method
 */
private void genTargetsMethod() {
    MethodVisitor mv = cw.visitMethod(ACC_PUBLIC+ACC_STATIC,
                                      "targets",
                                      "()" + MODULE_TARGET_ARRAY_SIGNATURE,
                                      "()" + MODULE_TARGET_ARRAY_SIGNATURE,
                                      null);
    mv.visitCode();
    pushInt(mv, moduleInfos.size());
    mv.visitTypeInsn(ANEWARRAY, MODULE_TARGET_CLASSNAME);
    mv.visitVarInsn(ASTORE, MT_VAR);

    for (int index=0; index < moduleInfos.size(); index++) {
        ModuleInfo minfo = moduleInfos.get(index);
        if (minfo.target() != null && !minfo.dropModuleTarget) {
            mv.visitVarInsn(ALOAD, MT_VAR);
            pushInt(mv, index);

            // new ModuleTarget(String, String)
            mv.visitTypeInsn(NEW, MODULE_TARGET_CLASSNAME);
            mv.visitInsn(DUP);
            mv.visitLdcInsn(minfo.target().targetPlatform());
            mv.visitMethodInsn(INVOKESPECIAL, MODULE_TARGET_CLASSNAME,
                "<init>", "(Ljava/lang/String;)V", false);

            mv.visitInsn(AASTORE);
        }
    }

    mv.visitVarInsn(ALOAD, MT_VAR);
    mv.visitInsn(ARETURN);
    mv.visitMaxs(0, 0);
    mv.visitEnd();
}
 
Example 13
public static void main(String[] args) throws NoSuchMethodException,SecurityException,
        IllegalAccessException,IllegalArgumentException,InvocationTargetException{
    ClassWriter cw=new ClassWriter(ClassWriter.COMPUTE_MAXS|ClassWriter.COMPUTE_FRAMES);
    cw.visit(V1_7,ACC_PUBLIC,"Example",null,"java/lang/Object",null);
    MethodVisitor mw=cw.visitMethod(ACC_PUBLIC,"<init>","()V",null,null);
    mw.visitVarInsn(ALOAD,0);
    mw.visitMethodInsn(INVOKESPECIAL,"java/lang/Object","<init>","()V");
    mw.visitInsn(RETURN);
    mw.visitMaxs(0,0);
    mw.visitEnd();
    mw=cw.visitMethod(ACC_PUBLIC+ACC_STATIC,"main","([Ljava/lang/String;)V",null,null);
    mw.visitFieldInsn(GETSTATIC,"java/lang/System","out","Ljava/io/PrintStream;");
    mw.visitLdcInsn("Hello world!");
    mw.visitMethodInsn(INVOKEVIRTUAL,"java/io/PrintStream","println","(Ljava/lang/String;)V");
    mw.visitInsn(RETURN);
    mw.visitMaxs(0,0);
    mw.visitEnd();
    byte[] code=cw.toByteArray();
    for(int i=0;i<1;i++){
        ClassLoader loader=UnloadClass.class.getClassLoader();
        Method m=ClassLoader.class.getDeclaredMethod("defineClass", String.class, byte[].class, int.class, int.class);
        m.setAccessible(true);
        m.invoke(loader,"Example",code,0,code.length);
        m.setAccessible(false);
        System.gc();
    }

}
 
Example 14
private byte[] loadClassData(String name) throws Exception {
    ClassWriter cw = new ClassWriter(0);
    MethodVisitor mv;
    switch (name) {
        case INTERFACE_NAME:
            cw.visit(V1_8, ACC_ABSTRACT | ACC_INTERFACE | ACC_PUBLIC, INTERFACE_NAME, null, "java/lang/Object", null);
            {
                mv = cw.visitMethod(ACC_PRIVATE, "privInstance", "()I", null, null);
                mv.visitCode();
                mv.visitLdcInsn(EXPECTED);
                mv.visitInsn(IRETURN);
                mv.visitMaxs(1, 1);
                mv.visitEnd();
            }
            break;
        case CLASS_NAME:
            cw.visit(52, ACC_SUPER | ACC_PUBLIC, CLASS_NAME, null, "java/lang/Object", new String[]{INTERFACE_NAME});
            {
                mv = cw.visitMethod(ACC_PUBLIC, "<init>", "()V", null, null);
                mv.visitCode();
                mv.visitVarInsn(ALOAD, 0);
                mv.visitMethodInsn(INVOKESPECIAL, "java/lang/Object", "<init>", "()V");
                mv.visitInsn(RETURN);
                mv.visitMaxs(1, 1);
                mv.visitEnd();
            }
            break;
        default:
            break;
    }
    cw.visitEnd();

    return cw.toByteArray();
}
 
Example 15
private byte[] loadClassData(String name) throws Exception {
    ClassWriter cw = new ClassWriter(0);
    MethodVisitor mv;
    switch (name) {
        case INTERFACE_NAME:
            cw.visit(V1_8, ACC_ABSTRACT | ACC_INTERFACE | ACC_PUBLIC, INTERFACE_NAME, null, "java/lang/Object", null);
            {
                mv = cw.visitMethod(ACC_PRIVATE, "privInstance", "()I", null, null);
                mv.visitCode();
                mv.visitLdcInsn(EXPECTED);
                mv.visitInsn(IRETURN);
                mv.visitMaxs(1, 1);
                mv.visitEnd();
            }
            break;
        case CLASS_NAME:
            cw.visit(52, ACC_SUPER | ACC_PUBLIC, CLASS_NAME, null, "java/lang/Object", new String[]{INTERFACE_NAME});
            {
                mv = cw.visitMethod(ACC_PUBLIC, "<init>", "()V", null, null);
                mv.visitCode();
                mv.visitVarInsn(ALOAD, 0);
                mv.visitMethodInsn(INVOKESPECIAL, "java/lang/Object", "<init>", "()V");
                mv.visitInsn(RETURN);
                mv.visitMaxs(1, 1);
                mv.visitEnd();
            }
            break;
        default:
            break;
    }
    cw.visitEnd();

    return cw.toByteArray();
}
 
Example 16
private byte[] loadClassData(String name) throws Exception {
    ClassWriter cw = new ClassWriter(0);
    MethodVisitor mv;
    switch (name) {
        case INTERFACE_NAME:
            cw.visit(V1_8, ACC_ABSTRACT | ACC_INTERFACE | ACC_PUBLIC, INTERFACE_NAME, null, "java/lang/Object", null);
            {
                mv = cw.visitMethod(ACC_PRIVATE, "privInstance", "()I", null, null);
                mv.visitCode();
                mv.visitLdcInsn(EXPECTED);
                mv.visitInsn(IRETURN);
                mv.visitMaxs(1, 1);
                mv.visitEnd();
            }
            break;
        case CLASS_NAME:
            cw.visit(52, ACC_SUPER | ACC_PUBLIC, CLASS_NAME, null, "java/lang/Object", new String[]{INTERFACE_NAME});
            {
                mv = cw.visitMethod(ACC_PUBLIC, "<init>", "()V", null, null);
                mv.visitCode();
                mv.visitVarInsn(ALOAD, 0);
                mv.visitMethodInsn(INVOKESPECIAL, "java/lang/Object", "<init>", "()V");
                mv.visitInsn(RETURN);
                mv.visitMaxs(1, 1);
                mv.visitEnd();
            }
            break;
        default:
            break;
    }
    cw.visitEnd();

    return cw.toByteArray();
}
 
Example 17
/**
 * Generate a class file with the given class name. The class implements Runnable
 * with a run method to invokestatic the given targetClass/targetMethod.
 */
byte[] generateRunner(String className,
                      String targetClass,
                      String targetMethod) throws Exception {

    ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS
                                     + ClassWriter.COMPUTE_FRAMES);
    cw.visit(V1_9,
            ACC_PUBLIC + ACC_SUPER,
            className.replace(".", "/"),
            null,
            "java/lang/Object",
            new String[] { "java/lang/Runnable" });

    // <init>
    MethodVisitor mv = cw.visitMethod(ACC_PUBLIC, "<init>", "()V", null, null);
    mv.visitVarInsn(ALOAD, 0);
    mv.visitMethodInsn(INVOKESPECIAL, "java/lang/Object", "<init>", "()V", false);
    mv.visitInsn(RETURN);
    mv.visitMaxs(0, 0);
    mv.visitEnd();

    // run()
    String tc = targetClass.replace(".", "/");
    mv = cw.visitMethod(ACC_PUBLIC, "run", "()V", null, null);
    mv.visitMethodInsn(INVOKESTATIC, tc, targetMethod, "()V", false);
    mv.visitInsn(RETURN);
    mv.visitMaxs(0, 0);
    mv.visitEnd();

    cw.visitEnd();
    return cw.toByteArray();
}
 
Example 18
private byte[] loadClassData(String name) throws Exception {
    ClassWriter cw = new ClassWriter(0);
    MethodVisitor mv;
    switch (name) {
       case CLASS_NAME_A:
            cw.visit(52, ACC_SUPER | ACC_PUBLIC, CLASS_NAME_A, null, "java/lang/Object", null);
            {
                mv = cw.visitMethod(ACC_PUBLIC, "<init>", "()V", null, null);
                mv.visitCode();
                mv.visitVarInsn(ALOAD, 0);
                mv.visitMethodInsn(INVOKESPECIAL, "java/lang/Object", "<init>", "()V");
                mv.visitInsn(RETURN);
                mv.visitMaxs(1, 1);
                mv.visitEnd();

                mv = cw.visitMethod(ACC_FINAL | ACC_STATIC, "m", "()I", null, null);
                mv.visitCode();
                mv.visitLdcInsn(FAILED);
                mv.visitInsn(IRETURN);
                mv.visitMaxs(1, 1);
                mv.visitEnd();
            }
            break;
        case CLASS_NAME_B:
            cw.visit(52, ACC_SUPER | ACC_PUBLIC, CLASS_NAME_B, null, CLASS_NAME_A, null);
            {
                mv = cw.visitMethod(ACC_PUBLIC, "<init>", "()V", null, null);
                mv.visitCode();
                mv.visitVarInsn(ALOAD, 0);
                mv.visitMethodInsn(INVOKESPECIAL, CLASS_NAME_A, "<init>", "()V");
                mv.visitInsn(RETURN);
                mv.visitMaxs(1, 1);
                mv.visitEnd();

                mv = cw.visitMethod(ACC_PUBLIC, "m", "()I", null, null);
                mv.visitCode();
                mv.visitLdcInsn(EXPECTED);
                mv.visitInsn(IRETURN);
                mv.visitMaxs(1, 1);
                mv.visitEnd();

            }
            break;
        default:
            break;
    }
    cw.visitEnd();

    return cw.toByteArray();
}
 
Example 19
/**
 * Returns the bytes for a class with name d_name (presumably "D" in some
 * package), extending some class with name sub_what, implementing p.I,
 * and defining two methods m() and m(11args) with access method_acc.
 *
 * @param d_name      Name of class that is defined
 * @param sub_what    Name of class that it extends
 * @param method_acc  Accessibility of method(s) m in defined class.
 * @return
 * @throws Exception
 */
public static byte[] bytesForSomeDsubSomethingSomeAccess
        (String d_name, String sub_what, int method_acc)
        throws Exception {

    ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_FRAMES
            | ClassWriter.COMPUTE_MAXS);
    MethodVisitor mv;
    String[] interfaces = {"p/I"};

    cw.visit(V1_8, ACC_PUBLIC + ACC_SUPER, d_name, null, sub_what, interfaces);
    {
        mv = cw.visitMethod(ACC_PUBLIC, "<init>", "()V", null, null);
        mv.visitCode();
        mv.visitVarInsn(ALOAD, 0);
        mv.visitMethodInsn(INVOKESPECIAL, sub_what, "<init>", "()V");
        mv.visitInsn(RETURN);
        mv.visitMaxs(0, 0);
        mv.visitEnd();
    }
    // int m() {return 3;}
    {
        mv = cw.visitMethod(method_acc, "m", "()I", null, null);
        mv.visitCode();
        mv.visitLdcInsn(new Integer(3));
        mv.visitInsn(IRETURN);
        mv.visitMaxs(0, 0);
        mv.visitEnd();
    }
    // int m(11args) {return 3;}
    {
        mv = cw.visitMethod(method_acc, "m", "(BCSIJ"
                + "Ljava/lang/Object;"
                + "Ljava/lang/Object;"
                + "Ljava/lang/Object;"
                + "Ljava/lang/Object;"
                + "Ljava/lang/Object;"
                + "Ljava/lang/Object;"
                + ")I", null, null);
        mv.visitCode();
        mv.visitLdcInsn(new Integer(3));
        mv.visitInsn(IRETURN);
        mv.visitMaxs(0, 0);
        mv.visitEnd();
    }
    cw.visitEnd();
    return cw.toByteArray();
}
 
Example 20
/**
 * Test a service provider that defines more than one no-args
 * public static "provider" method.
 */
@Test(expectedExceptions = ServiceConfigurationError.class)
public void testWithTwoFactoryMethods() throws Exception {
    Path mods = compileTest(TEST1_MODULE);

    ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS
                                     + ClassWriter.COMPUTE_FRAMES);
    cw.visit(V1_9,
            ACC_PUBLIC + ACC_SUPER,
            "p/ProviderFactory",
            null,
            "java/lang/Object",
            null);

    // public static p.Service provider()
    MethodVisitor mv = cw.visitMethod(ACC_PUBLIC + ACC_STATIC,
            "provider",
            "()Lp/Service;",
            null,
            null);
    mv.visitTypeInsn(NEW, "p/ProviderFactory$1");
    mv.visitInsn(DUP);
    mv.visitMethodInsn(INVOKESPECIAL,
            "p/ProviderFactory$1",
            "<init>", "()V",
            false);
    mv.visitInsn(ARETURN);
    mv.visitMaxs(0, 0);
    mv.visitEnd();

    // public static p.ProviderFactory$1 provider()
    mv = cw.visitMethod(ACC_PUBLIC + ACC_STATIC,
            "provider",
            "()Lp/ProviderFactory$1;",
            null,
            null);
    mv.visitTypeInsn(NEW, "p/ProviderFactory$1");
    mv.visitInsn(DUP);
    mv.visitMethodInsn(INVOKESPECIAL,
            "p/ProviderFactory$1",
            "<init>",
            "()V",
            false);
    mv.visitInsn(ARETURN);
    mv.visitMaxs(0, 0);
    mv.visitEnd();

    cw.visitEnd();

    // write the class bytes into the compiled module directory
    Path classFile = mods.resolve(TEST1_MODULE)
            .resolve("p")
            .resolve("ProviderFactory.class");
    Files.write(classFile, cw.toByteArray());

    // load providers and instantiate each one
    loadProviders(mods, TEST1_MODULE).forEach(Provider::get);
}