Examples with MethodVisitor net.bytebuddy.jar.asm.MethodVisitor used on opensource projects

Example 1 with MethodVisitor

use of net.bytebuddy.jar.asm.MethodVisitor in project beam by apache.

the class ByteBuddyUtils method createCollectionTransformFunction.

// When processing a container (e.g. List<T>) we need to recursively process the element type.
// This function
// generates a subclass of Function that can be used to recursively transform each element of the
// container.
static Class createCollectionTransformFunction(Type fromType, Type toType, Function<StackManipulation, StackManipulation> convertElement) {
    // Generate a TypeDescription for the class we want to generate.
    TypeDescription.Generic functionGenericType = TypeDescription.Generic.Builder.parameterizedType(Function.class, Primitives.wrap((Class) fromType), Primitives.wrap((Class) toType)).build();
    DynamicType.Builder<Function> builder = (DynamicType.Builder<Function>) BYTE_BUDDY.with(new InjectPackageStrategy((Class) fromType)).subclass(functionGenericType).method(ElementMatchers.named("apply")).intercept(new Implementation() {

        @Override
        public ByteCodeAppender appender(Target target) {
            return (methodVisitor, implementationContext, instrumentedMethod) -> {
                // this + method parameters.
                int numLocals = 1 + instrumentedMethod.getParameters().size();
                StackManipulation readValue = MethodVariableAccess.REFERENCE.loadFrom(1);
                StackManipulation stackManipulation = new StackManipulation.Compound(convertElement.apply(readValue), MethodReturn.REFERENCE);
                StackManipulation.Size size = stackManipulation.apply(methodVisitor, implementationContext);
                return new ByteCodeAppender.Size(size.getMaximalSize(), numLocals);
            };
        }

        @Override
        public InstrumentedType prepare(InstrumentedType instrumentedType) {
            return instrumentedType;
        }
    });
    return builder.visit(new AsmVisitorWrapper.ForDeclaredMethods().writerFlags(ClassWriter.COMPUTE_FRAMES)).make().load(ReflectHelpers.findClassLoader(((Class) fromType).getClassLoader()), ClassLoadingStrategy.Default.INJECTION).getLoaded();
}

Example 2 with MethodVisitor

use of net.bytebuddy.jar.asm.MethodVisitor in project powermock by powermock.

the class ClassFactory method create.

static byte[] create(String className) throws Exception {
    ClassWriter cw = new ClassWriter(0);
    MethodVisitor mv;
    cw.visit(49, ACC_PUBLIC + ACC_SUPER, className, null, "java/lang/Object", null);
    cw.visitSource("Hello.java", null);
    {
        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(1, 1);
        mv.visitEnd();
    }
    {
        mv = cw.visitMethod(ACC_PUBLIC + ACC_STATIC, "main", "([Ljava/lang/String;)V", null, null);
        mv.visitFieldInsn(GETSTATIC, "java/lang/System", "out", "Ljava/io/PrintStream;");
        mv.visitLdcInsn("hello");
        mv.visitMethodInsn(INVOKEVIRTUAL, "java/io/PrintStream", "println", "(Ljava/lang/String;)V", false);
        mv.visitInsn(RETURN);
        mv.visitMaxs(2, 1);
        mv.visitEnd();
    }
    cw.visitEnd();
    return cw.toByteArray();
}

Example 3 with MethodVisitor

use of net.bytebuddy.jar.asm.MethodVisitor in project reactor-core by reactor.

the class ReactorDebugClassVisitor method visitMethod.

@Override
public MethodVisitor visitMethod(int access, String currentMethod, String descriptor, String signature, String[] exceptions) {
    MethodVisitor visitor = super.visitMethod(access, currentMethod, descriptor, signature, exceptions);
    if (currentClassName.contains("CGLIB$$")) {
        return visitor;
    }
    String returnType = Type.getReturnType(descriptor).getInternalName();
    switch(returnType) {
        // because they don't have a type-preserving "checkpoint" method
        case "reactor/core/publisher/Flux":
        case "reactor/core/publisher/Mono":
        case "reactor/core/publisher/ParallelFlux":
            visitor = new ReturnHandlingMethodVisitor(visitor, returnType, currentClassName, currentMethod, currentSource, changed);
    }
    return new CallSiteInfoAddingMethodVisitor(visitor, currentClassName, currentMethod, currentSource, changed);
}