package javaxt.express;

import javaxt.express.ServiceRequest.Sort;

import javaxt.express.ServiceRequest.Field;

import javaxt.express.ServiceRequest.Filter;

import javaxt.express.utils.*;

import javaxt.sql.*;

import javaxt.json.*;

import javaxt.utils.Console;

import javaxt.http.servlet.ServletException;

import java.util.*;

import java.util.concurrent.ConcurrentHashMap;

import java.lang.reflect.Constructor;

import java.lang.reflect.Method;

import java.lang.reflect.Modifier;

import java.lang.reflect.Parameter;

//******************************************************************************

//** WebService

//******************************************************************************

/**

* Abstract class used to map HTTP requests to either virtual or concrete

* methods found in the extending class.

*

******************************************************************************/

public abstract class WebService {

private ConcurrentHashMap<String, DomainClass> classes = new ConcurrentHashMap<>();

private LinkedHashMap<String, ArrayList<Method>> serviceMethods = new LinkedHashMap<>();

private boolean strictLookup = false;

public static Console console = new Console(); //do not replace with static import!

private class DomainClass {

private Class c;

private boolean readOnly;

public DomainClass(Class c, boolean readOnly){

this.c = c;

this.readOnly = readOnly;

}

public boolean isReadOnly(){

return readOnly;

}

public String toString(){

return c.toString() + (readOnly ? " (readonly)" : "");

}

}

//**************************************************************************

//** Constructor

//**************************************************************************

public WebService(){

//Generate a list of all the service methods in the subclass. Service

//methods are public methods that accept a ServiceRequest parameter and

//return a ServiceResponse object. Implementation note:

//The getDeclaredMethod() method will only find methods declared in the

//current Class, not inherited from supertypes. So we may need to

//traverse up the concrete class hierarchy if this becomes a requirement.

for (Method m : this.getClass().getDeclaredMethods()){

if (Modifier.isPrivate(m.getModifiers())) continue;

if (m.getReturnType().equals(ServiceResponse.class)){

Class<?>[] params = m.getParameterTypes();

if (params.length>0){

if (ServiceRequest.class.isAssignableFrom(params[0])){

String key = m.getName();

if (!strictLookup) key = key.toLowerCase();

ArrayList<Method> methods = serviceMethods.get(key);

if (methods==null){

methods = new ArrayList<>();

serviceMethods.put(key, methods);

}

methods.add(m);

}

}

}

}

//Experimental special case for anonymous classes

if (this.getClass().isAnonymousClass()){

for (Method m : this.getClass().getMethods()){

if (Modifier.isPrivate(m.getModifiers())) continue;

if (m.getReturnType().equals(ServiceResponse.class)){

Class<?>[] params = m.getParameterTypes();

if (params.length>0){

if (ServiceRequest.class.isAssignableFrom(params[0])){

String key = m.getName();

if (!strictLookup) key = key.toLowerCase();

ArrayList<Method> methods = serviceMethods.get(key);

if (methods==null){

methods = new ArrayList<>();

serviceMethods.put(key, methods);

methods.add(m);

}

}

}

}

}

}

}

//**************************************************************************

//** addModel

//**************************************************************************

/** Register model that this service will support

* @param c A Java class that extends the javaxt.sql.Model abstract class.

*/

public void addModel(Class c){

addModel(c, false);

}

//**************************************************************************

//** addModel

//**************************************************************************

/** Register model that this service will support

* @param c A Java class that extends the javaxt.sql.Model abstract class.

* @param readOnly If true, the CRUD operations will be disabled. PUT,

* POST, and DELETE requests will be handled the same as GET requests.

*/

public void addModel(Class c, boolean readOnly){

if (!Model.class.isAssignableFrom(c)){

throw new IllegalArgumentException(c + " is not a javaxt.sql.Model");

}

String name = c.getSimpleName();

String pkg = c.getPackage().getName();

if (name.startsWith(pkg)) name = name.substring(pkg.length()+1);

name = name.toLowerCase();

int idx = name.lastIndexOf(".");

if (idx>0) name = name.substring(idx+1);

synchronized(classes){

classes.put(name, new DomainClass(c, readOnly));

classes.notify();

}

}

//**************************************************************************

//** addClass

//**************************************************************************

/** @deprecated Use addModel instead

*/

public void addClass(Class c){

addModel(c);

}

//**************************************************************************

//** addClass

//**************************************************************************

/** @deprecated Use addModel instead

*/

public void addClass(Class c, boolean readOnly){

addModel(c, readOnly);

}

//**************************************************************************

//** getServiceResponse

//**************************************************************************

/** Returns a ServiceResponse for a given request.

*/

public ServiceResponse getServiceResponse(ServiceRequest request)

throws ServletException {

return getServiceResponse(request, null);

}

//**************************************************************************

//** getServiceResponse

//**************************************************************************

/** Returns a ServiceResponse for a given request and database.

*/

public ServiceResponse getServiceResponse(ServiceRequest request, Database database)

throws ServletException {

//Get requested method. Note that the ServiceRequest typically prepends a

//keyword to the request path (e.g. get, save, delete) depending on the

//HTTP request method (e.g. GET, POST, PUT, DELETE)

String methodName = request.getMethod();

//Find a concrete implementation of the requested method in the subclass

if (!strictLookup) methodName = methodName.toLowerCase();

ArrayList<Method> methods = null;

if (serviceMethods.containsKey(methodName)){

methods = serviceMethods.get(methodName);

}

else{

int i = 0;

if (methodName.startsWith("get")) i = 4;

if (methodName.startsWith("save")) i = 5;

if (methodName.startsWith("delete")) i = 6;

if (i>0){

//Check for a simple method like search() or update() without a

//"get" or "save" or "delete" prefix

methodName = methodName.substring(i-1, i).toLowerCase() + methodName.substring(i);

methods = serviceMethods.get(methodName);

//Special case for POST requests (e.g. "POST /companies") that

//map to a "save" method (e.g. saveCompanies) that does not exist.

//Let's check if there's a suitable "get" method instead (e.g. getCompanies).

if (methods==null && i==5){ // && methodName.endsWith("s")

methods = serviceMethods.get("get" + methodName);

}

}

}

//Return ServiceResponse

if (methods!=null){

for (Method m : methods){

Class<?>[] params = m.getParameterTypes();

//Check whether the method accepts a ServiceRequest

//or ServiceRequest + Database as inputs

Object[] inputs = null;

if (params.length==1){

inputs = new Object[]{request};

}

else if (params.length==2){

if (Database.class.isAssignableFrom(params[1])){

inputs = new Object[]{request, database};

}

}

if (inputs!=null){

//Ensure that we don't want to invoke this function!

//For example, the caller might want to call

//super.getServiceResponse(request, database);

//If so, we would end up in a recursion causing a stack

//overflow. Instead of calling getServiceResponse()

//let's just flow down to the CRUD handlers below.

StackTraceElement[] stackTrace = new Exception().getStackTrace();

StackTraceElement el = stackTrace[1];

if (m.getName().equals(el.getMethodName())){

break;

}

//If we're still here, call the requested method and return

//the response

try{

m.setAccessible(true);

return (ServiceResponse) m.invoke(this, inputs);

}

catch(Exception e){

return getServiceResponse(e);

}

}

}

}

//If we're still here, see if the requested method corresponds to a

//standard CRUD operation.

String method = request.getMethod().toLowerCase(); //don't use methodName!

if (method.startsWith("get")){

//Find and return model

String className = method.substring(3);

DomainClass c = getClass(className);

if (c!=null) return get(c.c, request, database);

//Special case for plural-form of a model. Return list of models.

c = getClassFromPluralName(className);

if (c!=null) return list(c.c, request, database);

}

else if (method.startsWith("save")){

//Find model and save

String className = method.substring(4);

DomainClass c = getClass(className);

if (c!=null){

if (c.isReadOnly()){

return get(c.c, request, database);

}

else{

return save(c.c, request, database);

}

}

//Special case for plural-form of a model. Return list of models.

c = getClassFromPluralName(className);

if (c!=null) return list(c.c, request, database);

}

else if (method.startsWith("delete")){

String className = method.substring(6);

DomainClass c = getClass(className);

if (c!=null){

if (c.isReadOnly()){

return new ServiceResponse(403, "Delete access forbidden.");

}

else{

return delete(c.c, request, database);

}

}

}

return new ServiceResponse(501, "Not Implemented.");

}

//**************************************************************************

//** getRecordset

//**************************************************************************

/** Returns a Recordset that is used fetch records from the database and

* support CRUD operations. This is a protected method that extending

* classes can override to apply custom filters or add constraints when

* retrieving objects from the database. This method is called whenever an

* HTTP GET, POST, or DELETE request is made for a Model. It is perfectly

* acceptable to throw exceptions when overriding this method. When

* throwing exceptions, an IllegalArgumentException will return a HTTP 400

* error to the client and a SecurityException will return a 403 error. All

* other exceptions will return a 500 error.

* @param op Operation that is requesting the Recordset. Options include

* "list, "get", "save", and "delete".

* @param c The Model (Java class) associated with the request.

* @param sql The default SQL statement generated for the request.

* @param conn A database connection used to open the Recordset.

*/

protected Recordset getRecordset(ServiceRequest request, String op, Class c,

String sql, Connection conn) throws Exception {

Recordset rs = new Recordset();

if (op.equals("list")) rs.setFetchSize(1000);

rs.open(sql, conn);

return rs;

}

//**************************************************************************

//** get

//**************************************************************************

/** Used to retrieve an object from the database. Returns a JSON object.

*/

private ServiceResponse get(Class c, ServiceRequest request, Database database) {

try{

//Compile sql statement

HashMap<String, Object> tablesAndFields = getTableAndFields(c);

String tableName = (String) tablesAndFields.get("tableName");

String sql = "select " + tableName + ".id from " + tableName +

" where ";

Long id = request.getID();

if (id==null){

String where = request.getWhereStatement(tablesAndFields);

if (where==null) return new ServiceResponse(404);

else sql += where;

}

else{

sql += tableName + ".id=" + id;

}

//Apply filter

try (Connection conn = database.getConnection()){

try (Recordset rs = getRecordset(request, "get", c, sql, conn)){

if (rs.EOF) id = null;

else id = rs.getValue("id").toLong();

}

}

if (id==null) return new ServiceResponse(404);

Object obj = newInstance(c, id);

Method toJson = getMethod("toJson", c);

return new ServiceResponse((JSONObject) toJson.invoke(obj));

}

catch(Exception e){

return getServiceResponse(e);

}

}

//**************************************************************************

//** list

//**************************************************************************

/** Used to retrieve a shallow list of objects from the database.

*/

private ServiceResponse list(Class c, ServiceRequest request, Database database){

//Get tableName and fields associated with the Model

HashMap<String, Object> tablesAndFields;

HashSet<String> spatialFields;

String tableName;

try{

tablesAndFields = getTableAndFields(c);

tableName = (String) tablesAndFields.get("tableName");

spatialFields = (HashSet<String>) tablesAndFields.get("spatialFields");

}

catch(Exception e){

return getServiceResponse(e);

}

//Compile SQL statement

StringBuilder sql = new StringBuilder("select ");

sql.append(request.getSelectStatement(tablesAndFields));

sql.append(" from ");

sql.append(tableName);

String where = request.getWhereStatement(tablesAndFields);

if (where!=null){

sql.append(" where ");

sql.append(where);

}

Long offset = request.getOffset();

if (offset==null || offset<1){

sql.append(request.getOrderByStatement());

}

else{

//Add ID (unique primary key) to the order by statement as needed.

//This is important when paginating sorting on non-distinct columns (esp on H2)

Sort sort = request.getSort();

if (!sort.isEmpty()){

sql.append(" order by ");

boolean addID = true;

java.util.Iterator<String> it = sort.getKeySet().iterator();

while (it.hasNext()){

String colName = it.next();

String direction = sort.get(colName);

sql.append(colName);

sql.append(" ");

sql.append(direction);

if (it.hasNext()) sql.append(", ");

if (colName.equalsIgnoreCase("id")) addID = false;

}

if (addID) sql.append(", id");

}

}

sql.append(request.getOffsetLimitStatement(database.getDriver()));

//console.log(sql);

//Get output format

String format = request.getFormat();

//Excute query and generate response

try (Connection conn = database.getConnection()){

try (Recordset rs = getRecordset(request, "list", c, sql.toString(), conn)){

ServiceResponse response;

if (format.equals("csv")){

StringBuilder csv = new StringBuilder();

long x = 0;

while (rs.next()){

if (x>0) csv.append("\r\n");

//Add header row as needed

if (x==0){

int i = 0;

HashSet<String> fieldNames = new HashSet<>();

for (javaxt.sql.Field field : rs.getFields()){

String fieldName = field.getName().toLowerCase();

if (fieldNames.contains(fieldName)) continue;

fieldNames.add(fieldName);

if (i>0) csv.append(",");

csv.append(fieldName);

i++;

}

csv.append("\r\n");

}

//Add data row

int i = 0;

HashSet<String> fieldNames = new HashSet<>();

for (javaxt.sql.Field field : rs.getFields()){

String fieldName = field.getName().toLowerCase();

if (fieldNames.contains(fieldName)) continue;

fieldNames.add(fieldName);

if (i>0) csv.append(",");

javaxt.sql.Value value = field.getValue();

if (!value.isNull()){

String val = value.toString();

//Update spatial data as needed

fieldName = StringUtils.underscoreToCamelCase(fieldName);

if (spatialFields.contains(fieldName)){

if (database.getDriver().equals("PostgreSQL")){

val = createGeom(val.toString()).toString();

}

}

if (val.contains("\"") || val.contains(",")){

val = "\"" + val + "\"";

}

csv.append(val);

}

i++;

}

x++;

}

response = new ServiceResponse(csv);

response.setContentType("text/csv");

}

else if (format.equals("json")){

StringBuilder arr = new StringBuilder("[");

long x = 0;

while (rs.next()){

JSONObject json = DbUtils.getJson(rs);

//Update spatial data as needed

for (String fieldName : json.keySet()){

JSONValue val = json.get(fieldName);

if (!val.isNull()){

if (spatialFields.contains(fieldName)){

if (database.getDriver().equals("PostgreSQL")){

val = new JSONValue(createGeom(val.toString()));

json.set(fieldName, val);

}

}

}

}

if (x>0) arr.append(",");

arr.append(json);

x++;

}

arr.append("]");

response = new ServiceResponse(arr.toString());

response.setContentType("application/json");

}

else {

long x = 0;

JSONArray cols = new JSONArray();

StringBuilder json = new StringBuilder("{\"rows\":[");

while (rs.next()){

JSONArray row = new JSONArray();

HashSet<String> fieldNames = new HashSet<>();

for (javaxt.sql.Field field : rs.getFields()){

String fieldName = field.getName().toLowerCase();

fieldName = StringUtils.underscoreToCamelCase(fieldName);

if (fieldNames.contains(fieldName)) continue;

fieldNames.add(fieldName);

if (x==0) cols.add(fieldName);

JSONObject f = field.toJson();

JSONValue val = f.get("value");

//Update spatial data as needed

if (!val.isNull()){

if (spatialFields.contains(fieldName)){

if (database.getDriver().equals("PostgreSQL")){

val = new JSONValue(createGeom(val.toString()));

}

}

}

row.add(val);

}

if (x>0) json.append(",");

json.append(row.toString());

x++;

}

json.append("]");

//Append columns

json.append(",\"cols\":");

json.append(cols.toString());

//Append count as needed

if (request.getCount()){

rs.close();

Record r = conn.getRecord("select count(id) from " +

tableName + (where==null ? "" : " where " + where));

if (r!=null){

json.append(",\"count\":");

json.append(r.get(0).toLong());

}

}

json.append("}");

response = new ServiceResponse(json.toString());

response.setContentType("application/json");

}

return response;

}

}

catch(Exception e){

return getServiceResponse(e);

}

}

//**************************************************************************

//** save

//**************************************************************************

/** Used to create or update an object in the database. Returns the object

* ID.

*/

private ServiceResponse save(Class c, ServiceRequest request, Database database) {

try{

//Parse json

JSONObject json = request.getJson();

if (json==null || json.isEmpty()) throw new Exception("JSON is empty.");

Long id = json.get("id").toLong();

boolean isNew = id==null;

//Apply filter

HashMap<String, Object> tablesAndFields = getTableAndFields(c);

String tableName = (String) tablesAndFields.get("tableName");

String sql = "select " + tableName + ".id from " + tableName +

" where " + tableName + ".id=" + (id==null ? -1 : id);

try (Connection conn = database.getConnection()){

try (Recordset rs = getRecordset(request, "save", c, sql, conn)){

if (rs.EOF) id = null;

else id = rs.getValue("id").toLong();

}

}

if (id==null && !isNew) return new ServiceResponse(404);

//Reparse json (json may have changed in getRecordset)

json = request.getJson();

id = json.get("id").toLong();

isNew = id==null;

//Create new instance of the class

Object obj;

if (id!=null){

obj = newInstance(c, id);

beforeUpdate(obj, request);

Method update = c.getDeclaredMethod("update", JSONObject.class);

update.invoke(obj, new Object[]{json});

}

else{

obj = newInstance(c, json);

beforeCreate(obj, request);

isNew = true;

}

//Call the save method

Method save = getMethod("save", c);

save.invoke(obj);

//Get id

Method getID = getMethod("getID", c);

id = (Long) getID.invoke(obj);

if (id==null) return new ServiceResponse(500, "Failed to retrieve ID on save");

//Fire event

if (isNew) onCreate(obj, request);

else onUpdate(obj, request);

//Return response

return new ServiceResponse(id+"");

}

catch(Exception e){

return getServiceResponse(e);

}

}

//**************************************************************************

//** delete

//**************************************************************************

/** Used to delete an object in the database. Returns a JSON representation

* of the object that was deleted.

*/

private ServiceResponse delete(Class c, ServiceRequest request, Database database) {

try (Connection conn = database.getConnection()){

//Apply filter

Long id = request.getID();

try (Recordset rs = getRecordset(request, "delete", c,

"select id from " + getTableName(c.newInstance()) +

" where id=" + id, conn)){

if (rs.EOF) id = null;

else id = rs.getValue("id").toLong();

}

if (id==null) return new ServiceResponse(404);

//Reparse request to get ID (id may have changed in getRecordset)

Long newID = request.getParameter("id").toLong();

if (newID!=null) id = newID;

//Create new instance of the class

Object obj = newInstance(c, id);

//Fire event

beforeDelete(obj, request);

//Delete object

Method delete = getMethod("delete", c);

delete.invoke(obj);

//Fire event

onDelete(obj, request);

//Return response

Method toJson = getMethod("toJson", c);

JSONObject json = (JSONObject) toJson.invoke(obj);

return new ServiceResponse(json);

}

catch(Exception e){

return getServiceResponse(e);

}

}

//**************************************************************************

//** beforeCreate

//**************************************************************************

/** This method is called immediately before a record is inserted into the

* database. Override this method to process the event.

* @param obj Object. If this method is called by this class, the Object

* will correspond to an instance of a javaxt.sql.Model

*/

public void beforeCreate(Object obj, ServiceRequest request){};

//**************************************************************************

//** onCreate

//**************************************************************************

/** This method is called immediately after a record is inserted into the

* database. Override this method to process the event.

* @param obj Object. If this method is called by this class, the Object

* will correspond to an instance of a javaxt.sql.Model

*/

public void onCreate(Object obj, ServiceRequest request){};

//**************************************************************************

//** beforeUpdate

//**************************************************************************

/** This method is called immediately before a record is updated in the

* database. Override this method to process the event.

* @param obj Object. If this method is called by this class, the Object

* will correspond to an instance of a javaxt.sql.Model

*/

public void beforeUpdate(Object obj, ServiceRequest request){};

//**************************************************************************

//** onUpdate

//**************************************************************************

/** This method is called immediately after a record is updated in the

* database. Override this method to process the event.

* @param obj Object. If this method is called by this class, the Object

* will correspond to an instance of a javaxt.sql.Model

*/

public void onUpdate(Object obj, ServiceRequest request){};

//**************************************************************************

//** beforeDelete

//**************************************************************************

/** This method is called immediately before a record is deleted in the

* database. Override this method to process the event.

* @param obj Object. If this method is called by this class, the Object

* will correspond to an instance of a javaxt.sql.Model

*/

public void beforeDelete(Object obj, ServiceRequest request){};

//**************************************************************************

//** onDelete

//**************************************************************************

/** This method is called immediately after a record is deleted in the

* database. Override this method to process the event.

* @param obj Object. If this method is called by this class, the Object

* will correspond to an instance of a javaxt.sql.Model

*/

public void onDelete(Object obj, ServiceRequest request){};

//**************************************************************************

//** getClass

//**************************************************************************

/** Returns a class from the list of known/supported classes for a given

* class name. Performs an exact match.

*/

private DomainClass getClass(String className){

synchronized(classes){

return classes.get(className);

}

}

//**************************************************************************

//** getClassFromPluralName

//**************************************************************************

/** Returns a class from the list of known/supported classes for a plural

* form of a class name.

*/

private DomainClass getClassFromPluralName(String className){

if (className==null) return null;

//Check for common plural suffixes

if (className.endsWith("ies")){ //Categories == Category

if (className.length() > 3){

char beforeIes = className.charAt(className.length()-4);

if (!"aeiou".contains(String.valueOf(beforeIes).toLowerCase())){

return getClass(className.substring(0, className.length()-3) + "y");

}

}

}

else if (className.endsWith("sses")){ //Classes == Class

return getClass(className.substring(0, className.length()-2));

}

else if (className.endsWith("ches")){ //Matches == Match

return getClass(className.substring(0, className.length()-2));

}

else if (className.endsWith("shes")){ //Dishes == Dish

return getClass(className.substring(0, className.length()-2));

}

else if (className.endsWith("xes")){ //Boxes == Box

return getClass(className.substring(0, className.length()-2));

}

else if (className.endsWith("zzes")){ //Buzzes == Buzz

return getClass(className.substring(0, className.length()-2));

}

else if (className.endsWith("ses")){ //Viruses = Virus, Gases = Gas

return getClass(className.substring(0, className.length()-2));

}

//If we're still here, try stripping out the last "s"

if (className.endsWith("s")){ //Sources == Source, Premises = Premise

return getClass(className.substring(0, className.length()-1));

}

//If we're still here, check for common irregular plurals

if (className.equalsIgnoreCase("men")) return getClass("Man");

if (className.equalsIgnoreCase("women")) return getClass("Woman");

if (className.equalsIgnoreCase("people")) return getClass("Person");

if (className.equalsIgnoreCase("children")) return getClass("Child");

if (className.equalsIgnoreCase("indices")) return getClass("Index");

if (className.equalsIgnoreCase("vertices")) return getClass("Vertex");

if (className.equalsIgnoreCase("analyses")) return getClass("Analysis");

if (className.equalsIgnoreCase("criteria")) return getClass("Criterion");

return null;

}

//**************************************************************************

//** getMethod

//**************************************************************************

/** Returns a declared (public) method defined in a given class.

*/

private Method getMethod(String name, Class clazz){

while (clazz != null) {

Method[] methods = clazz.getDeclaredMethods();

for (Method method : methods) {

if (method.getName().equals(name)) {

return method;

}

}

clazz = clazz.getSuperclass();

}

return null;

}

//**************************************************************************

//** newInstance

//**************************************************************************

/** Returns a new instance for a given class using an ID and a connection to

* the database.

*/

private Object newInstance(Class c, long id) throws Exception {

Constructor constructor = c.getDeclaredConstructor(new Class[]{Long.TYPE});

return constructor.newInstance(new Object[]{id});

}

//**************************************************************************

//** newInstance

//**************************************************************************

/** Returns a new instance for a given class using a JSON object.

*/

private Object newInstance(Class c, JSONObject json) throws Exception {

Constructor constructor = c.getDeclaredConstructor(new Class[]{JSONObject.class});

return constructor.newInstance(new Object[]{json});

}

//**************************************************************************

//** getTableName

//**************************************************************************

/** Returns the "tableName" private variable associated with a model

*/

private String getTableName(Object obj) throws Exception {

java.lang.reflect.Field field = obj.getClass().getSuperclass().getDeclaredField("tableName");

field.setAccessible(true);

String tableName = (String) field.get(obj);

return tableName;

}

//**************************************************************************

//** getTableAndFields

//**************************************************************************

/** Returns a HashMap with the table name and fields associated with a given

* model.

*/

protected static HashMap<String, Object> getTableAndFields(Class c) throws Exception {

String tableName;

HashMap<String, String> fieldMap = new HashMap<>();

HashSet<String> stringFields = new HashSet<>();

HashSet<String> arrayFields = new HashSet<>();

HashSet<String> spatialFields = new HashSet<>();

Object obj = c.newInstance(); //maybe clone instead?

//Get tableName

java.lang.reflect.Field field = obj.getClass().getSuperclass().getDeclaredField("tableName");

field.setAccessible(true);

tableName = (String) field.get(obj);

//Get fieldMap

field = obj.getClass().getSuperclass().getDeclaredField("fieldMap");

field.setAccessible(true);

HashMap<String, String> map = (HashMap<String, String>) field.get(obj);

Iterator<String> it = map.keySet().iterator();

while (it.hasNext()){

String fieldName = it.next();

String columnName = map.get(fieldName);

fieldMap.put(fieldName, columnName);