Create a groovy proxy from bean/interface

GroovyGsonShimFactory.java

import groovy.lang.GroovyClassLoader;
import org.apache.commons.beanutils.PropertyUtils;

import java.beans.PropertyDescriptor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.LinkedHashMap;
import java.util.Map;

public class GroovyGsonShimFactory {
  private  Map<Class, Method> shimMethods = new LinkedHashMap<>();

  private void generateGroovyProxy(Class ifaceClass) {
    String c1 = ifaceClass.getSimpleName() + "$Proxy";
    String s = "public class " + c1 + " implements " + ifaceClass.getCanonicalName() + "\n{";


    {
      PropertyDescriptor[] propertyDescriptors = PropertyUtils.getPropertyDescriptors(ifaceClass);
      for (PropertyDescriptor p : propertyDescriptors) {
        String name = p.getName();
        String tname = p.getPropertyType().getCanonicalName();
        s += "public " + tname + " " + name + ";\n";
        s += " " + p.getReadMethod().toGenericString().replace("abstract", "").replace(ifaceClass.getCanonicalName() + ".", "") + "{return " + name + ";};\n";
        Method writeMethod = p.getWriteMethod();
        if (writeMethod != null)
          s += " " + writeMethod.toGenericString().replace("abstract", "").replace(ifaceClass.getCanonicalName() + ".", "").replace(")", " v){" + name + "=v;};") + "\n\n";
      }
    }
    s += "public static " + c1 +
        " fromJson(String s){return new com.google.gson.Gson().fromJson(s," + c1 + ");};\n";
    s += "\n};";
    System.err.println("" + s);
    ClassLoader parent = DefaultDriver.class.getClassLoader();
    GroovyClassLoader loader = new GroovyClassLoader(parent);

    Class gClass = loader.parseClass(s);
    try {

      Method shimMethod = gClass.getMethod("fromJson", String.class);
      shimMethods.put(ifaceClass, shimMethod);

    } catch (NoSuchMethodException e) {
      e.printStackTrace(); //todo: review for a purpose
    }

  }

  public <T> T getShim(String json, Class<T> ifaceClass) {
    if (!shimMethods.containsKey(ifaceClass)) generateGroovyProxy(ifaceClass);
    T shim = null;//= gson().shimMethods(json, CowSchema.class);
    try {
      shim = (T) shimMethods.get(ifaceClass).invoke(null, json);
    } catch (IllegalAccessException | InvocationTargetException e) {
      e.printStackTrace(); //todo: review for a purpose
    }
    return shim;
  }
}