JsonActionInterceptor

JsonActionInterceptor.java

package com.klopaj.interceptor;

import com.klopaj.interceptor.meta.JsonAction;
import com.klopaj.interceptor.meta.JsonIn;
import flexjson.JSONDeserializer;
import flexjson.JSONSerializer;
import jodd.bean.BeanUtil;
import jodd.madvoc.ActionRequest;
import jodd.madvoc.interceptor.ActionInterceptor;
import jodd.servlet.ServletUtil;

import javax.servlet.http.HttpServletRequest;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.lang.reflect.ParameterizedType;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Map;


public class JsonActionInterceptor extends ActionInterceptor {
    @Override
    public Object intercept(ActionRequest actionRequest) throws Exception {
        HttpServletRequest request = actionRequest.getHttpServletRequest();


        Object action = actionRequest.getAction();
        Method method = actionRequest.getActionConfig().getActionClassMethod();

        if (method.isAnnotationPresent(JsonAction.class)) {
            // if this is a json action, get all @JsonIn fields, and try to parse them from input

            String jsonStringValue = ServletUtil.readRequestBody(request);
            Object fieldValues = new JSONDeserializer<Object>().deserialize(jsonStringValue);

            List<Field> fields = getAllDeclaredFields(action.getClass());
            for (Field field : fields) {
                if (field != null) {
                    if (field.isAnnotationPresent(JsonIn.class)) {
                        // This field is marked as @JsonIn meaning it should be in the content of the response
                        addFieldValueToObject(action, fieldValues, field);
                    }
                }
            }
        }

        return actionRequest.invoke();
    }

    private void addFieldValueToObject(Object action, Object fieldValues, Field field) throws IllegalAccessException, InstantiationException {
        Class fieldType = field.getType();
        if (fieldType == String.class || fieldType.isPrimitive() || Number.class.isAssignableFrom(fieldType)) {
            // it's simple string, just try to get that value from json
            Object fieldValue = getFieldValue(field.getName(), fieldValues);
            field.setAccessible(true);
            field.set(action, fieldValue);
        } else if (List.class.isAssignableFrom(fieldType)) {
            // Handle lists and similar
            System.out.println("It's a collection");

            List fieldValue = (List) getFieldValue(field.getName(), fieldValues);
            if (field.getGenericType() instanceof ParameterizedType) {
                ParameterizedType itemParameterizedType = (ParameterizedType) field.getGenericType();
                Class itemType = (Class) itemParameterizedType.getActualTypeArguments()[0];

                List result = new ArrayList();
                for (Object object : fieldValue) {
                    if (object != null) {
                        System.out.println("Collection item " + object);

                        Object itemInstance = itemType.newInstance();

                        // Object is most likely HashMap
                        if (object instanceof Map) {
                            Map<String, Object> objectAsMap = (Map<String, Object>) object;


                            for (Field itemField : getAllDeclaredFields(itemInstance.getClass())) {
                                if (objectAsMap.get(itemField.getName()) != null) {
                                    // we have that field's value
                                    addFieldValueToObject(itemInstance, objectAsMap, itemField);
                                }
                            }

                        }

                        result.add(itemInstance);
                    }
                }

                BeanUtil.setDeclaredPropertyForced(action, field.getName(), result);
            }
        } else {
            // Most likely this is a POJO.
            Object fieldValue = getFieldValue(field.getName(), fieldValues);

            // TODO: "Number.class" part is a hack cause current Entity (hibernate) Id is marked as "extends Serializable", but the value is always a number.
            if (fieldValue.getClass().isPrimitive() || Number.class.isAssignableFrom(fieldValue.getClass())) {

                field.setAccessible(true);
                field.set(action, fieldValue);
            } else {
                String objectSerialized = new JSONSerializer().exclude("*.class").serialize(fieldValue);

                Object fieldValueObject = new JSONDeserializer().deserialize(objectSerialized, fieldType);
                field.setAccessible(true);
                field.set(action, fieldValueObject);
            }

        }
    }

    private Object getFieldValue(String fieldName, Object fieldValues) {
        if (fieldValues instanceof Map) {
            Map mapFieldValue = (Map) fieldValues;
            return mapFieldValue.get(fieldName);
        }

        return null;
    }

    /**
     * Returns all declared fields (including all supper classes' fields)
     *
     * @param type Class object that we need to get it's declared fields
     * @return List of Fields
     */
    public List<Field> getAllDeclaredFields(Class<?> type) {
        List<Field> result = new ArrayList<Field>();
        return getAllDeclaredFields(result, type);

    }

    private List<Field> getAllDeclaredFields(List<Field> fields, Class<?> type) {
        Collections.addAll(fields, type.getDeclaredFields());

        if (type.getSuperclass() != null) {
            fields = getAllDeclaredFields(fields, type.getSuperclass());
        }

        return fields;
    }
}