Invoking a method with generic parms using reflection

Question

I am trying to pass two generics with known types (accumulationFunction, resultBindings) into the reflective invoke routine below, but I'm having trouble. Can someone help me understand how this can be achieved?

package com.amir.method.compiler;

//hidden imports

import java.util.Set;

public class CompiledReferencedAttributeMethod implements CompiledMethod {

    final Class<?> generatedClazz;
    //how do i pass the arguments below into the invoke routine??
    final KnownWorkData<AccumulationFunction> accumulationFunction;
    final KnownWorkData<Set<Executable<InstanceSetValue>>> resultBindings;

    public CompiledReferencedAttributeMethod(final int hash,
                                             final KnownWorkData<AccumulationFunction> accumulationFunction,
                                             final KnownWorkData<Set<Executable<InstanceSetValue>>> resultBindings) {
        this.generatedClazz = ReferencedAttributeMethodGenerator.get().compileMethod(
                "com.amir.hotspot.GeneratedGRAMethod" +hash, "dynamicGra", accumulationFunction, resultBindings);
        this.accumulationFunction = accumulationFunction;
        this.resultBindings = resultBindings;
    }

    @Override
    public WorkDataValue invokeCompiled(final Instance onInst,
                                        final ExecutionParms parm,
                                        final WorkDataDefinition returntype,
                                        final TaskContext context) {
        try {
            return (WorkDataValue) this.generatedClazz
                    .getMethod("dynamicGra",
                            Instance.class,
                            ExecutionParms.class,
                            WorkDataDefinition.class,
                            TaskContext.class)
                    .invoke(null, onInst, parm, returntype, this.accumulationFunction, this.resultBindings, context);
        } catch(Exception e) {
            throw new ExecuteCompiledMethodException(this.toString(), e);
        }
    }

}

Answer 1

As you cannot overload method with generics and different parameters (see: Oracle’s tutorial “Restrictions on Generics”) you don't have to bother about generics with the reflection API.

There is no ambiguity, you can simply get your method like that:

Method m = this.generatedClazz.getMethod("dynamicGra",
                            Instance.class,
                            ExecutionParms.class,
                            WorkDataDefinition.class,
                            KnownWorkData.class,
                            KnownWorkData.class,
                            TaskContext.class);

Then you invoked with null so it means that dynamicGra must be static, if it's not the case you must pass the instance of generatedClazz on which you want to call the method :

Object instance = this.generatedClazz.newInstance(); // A new one or any other reference of generatedClazz
m.invoke(instance, onInst, parm, returntype, this.accumulationFunction, this.resultBindings, context);