Generic usage of Google Ads API using reflection

Generic usage of Google Ads API using reflection

import java.lang.reflect.AccessibleObject;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import com.google.ads.googleads.v6.services.GoogleAdsVersion;
import com.google.api.gax.core.BackgroundResource;
import com.google.protobuf.AbstractMessage;

public class GoogleUtils {
    @SuppressWarnings({"rawtypes", "unchecked", "unused"})
    private <GoogleEntity extends AbstractMessage> void executeGoogleOperation(
									       Class<? extends AbstractMessage> googleEntityType,
									       Map<String, Object> fields) throws Throwable {
	final String entityName = googleEntityType.getSimpleName();
	Method curMethod = null;
	BackgroundResource svcCli = null;
	Object instance = null;
	try {
	    // Get the service client (e.g., CampaignServiceClient)
	    String svcCliCreator = "create" + entityName + "ServiceClient";
	    curMethod = googleClient.getClass().getMethod(svcCliCreator);
	    instance = googleClient;
	    AccessibleObject.setAccessible(new AccessibleObject[] {curMethod}, true);
	    svcCli = (BackgroundResource) curMethod.invoke(instance);
	    Class svcCliClass = svcCli.getClass();
	    // Get builder creation method (e.g., Campaign.newBuilder()
	    curMethod = googleEntityType.getMethod("newBuilder");
	    // Instance is builder for the googleEntity
	    instance = curMethod.invoke(null);
	    Class builderClass = instance.getClass();
	    
	    // Build the instance of GoogleEntity
	    // Method [] builderMethods = builderClass.getMethods();
	    for (String field : fields.keySet()) {
		String setterName = "set" + Character.toUpperCase(field.charAt(0)) + field.substring(1);
		Object val = fields.get(field);
		curMethod = builderClass.getMethod(setterName, val.getClass());
		instance = curMethod.invoke(instance, val);
	    }
	    curMethod = builderClass.getMethod("build");
	    GoogleEntity googleEntity = (GoogleEntity) curMethod.invoke(instance);

	    String resourcePkg = googleEntityType.getPackage().getName();
	    String servicePkg = resourcePkg.substring(0, resourcePkg.lastIndexOf(".")) + ".services";
	    
	    Class opClass = Class.forName(servicePkg + "." + entityName + "Operation");
	    // Ops builder
	    curMethod = opClass.getMethod("newBuilder");
	    // instance is builder for operation
	    instance = curMethod.invoke(instance);
	    builderClass = instance.getClass();
	    curMethod = builderClass.getMethod("setCreate", googleEntityType);
	    instance = curMethod.invoke(instance, googleEntity);
	    // get the builder method
	    curMethod = builderClass.getMethod("build");
	    // instance is the entity operation
	    instance = curMethod.invoke(instance);
	    List ops = new ArrayList();
	    ops.add(instance);
	    // get the mutator method
	    curMethod = svcCliClass.getMethod("mutate" + entityName + "s", String.class, List.class);
	    // invoke mutator
	    Object mutateResponse = curMethod.invoke(svcCli, customerId, ops);
	    // get getResultsList() method
	    curMethod = mutateResponse.getClass().getMethod("getResultsList");
	    List responses = (List) curMethod.invoke(mutateResponse);
	    String resourceName = (String) responses.get(0);
	} finally {
	    if (svcCli != null) {
		try {
		    svcCli.close();
		} catch (Exception e) {
		}
	    }
	}
    }
}