Examples with Function org.apache.beam.vendor.guava.v26_0_jre.com.google.common.base.Function used on opensource projects

Example 1 with Function

use of org.apache.beam.vendor.guava.v26_0_jre.com.google.common.base.Function 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();
}