JSON: {productDetails=[{amount=20000.0, rValue=10000.00}, {amount=80000.0, rValue=6000.00} {amount=70000.0, rValue=0}]
I have to get the totalValue based on rValue and amount.
if rValue != 0 then sum only rValues thats is 10000+6000 = 16000 Else, get the amount = 70000
and then totalValue = rvalues + amount (16000+70000)
Please, can anyone suggest how can I in Java8.
List<Map> products= (List)products.get("productDetails");
for (Map<String, Object> scheme : products) {
log.info("scheme " + scheme.toString());
BigDecimal rValue = Optional.ofNullable(scheme.get("rValue "))
.map(Object::toString)
.map(BigDecimal::new)
.orElse(BigDecimal.ZERO);
BigDecimal amount = Optional.ofNullable(scheme.get("amount"))
.map(Object::toString)
.map(BigDecimal::new)
.orElse(BigDecimal.ZERO);
log.debug("rValue : " + rValue );
log.debug("amount: " + amount);
What you need is:
BigDecimal reduced = products.stream().map(x -> {
if (x.getrValue() != BigDecimal.ZERO)
return x.getrValue();
else return x.getAmount();
}).reduce(BigDecimal.ZERO, BigDecimal::add);
Complete example:
public class Ex1 {
public static void main(String[] args) {
List<Product> products = new ArrayList<>(Arrays.asList(
new Product(new BigDecimal(20000), new BigDecimal(10000)),
new Product(new BigDecimal(80000), new BigDecimal(6000)),
new Product(new BigDecimal(70000), BigDecimal.ZERO)
));
BigDecimal reduced = products.stream().map(x -> {
if (x.getrValue() != BigDecimal.ZERO)
return x.getrValue();
else return x.getAmount();
}).reduce(BigDecimal.ZERO, BigDecimal::add);
System.out.println(reduced);
}
}
class Product {
BigDecimal amount;
BigDecimal rValue;
public Product(BigDecimal amount, BigDecimal rValue) {
this.amount = amount;
this.rValue = rValue;
}
public BigDecimal getAmount() {
return amount;
}
public void setAmount(BigDecimal amount) {
this.amount = amount;
}
public BigDecimal getrValue() {
return rValue;
}
public void setrValue(BigDecimal rValue) {
this.rValue = rValue;
}
}
and the result is: 86000
Create POJO object of
long amount, rValue
Turn your JSON to a list of these objects (using Gson / Jackson).
Stream the list and apply your business logic.
Related
Suppose a JSON column called blob in a MySQL 5.7 database table called "Thing" with the following content:
[
{
"id": 1,
"value": "blue"
},
{
"id": 2,
"value": "red"
}
]
Is it possible to select all records from Thing where the blob contains an object within the array where the id is some dynamic value and the value is also some dynamic value.
E.g. "give me all Things where the blob contains an object whose id is 2 and value is 'red'"
Not sure how to form the WHERE clause below:
SET #id = 2;
SET #value1 = 'red';
SET #value2 = 'blue';
-- with equals?
SELECT *
FROM Thing
WHERE JSON_EXTRACT(blob, '$[*].id ... equals #id ... and .value') = #value1;
-- with an IN clause?
SELECT *
FROM Thing
WHERE JSON_EXTRACT(blob, '$[*].id ... equals #id ... and .value') IN (#value1, #value2);
They said it couldn't be done. They told me I was a fool. Lo and behold, I have done it!
Here are some helper functions to teach Hibernate how to perform JSON functions against a MySQL 5.7 backend, and an example use case. It's confusing, for sure, but it works.
Context
This contrived example is of a Person entity which can have many BioDetails, which is a question/answer type (but is more involved than that). The example within below essentially is searching within two JSON payloads, grabbing JSON values from one to build JSON paths within which to search in the other. In the end, you can pass in a complex structure of AND'd or OR'd criteria, which will be applied against a JSON blob and return only the resulting rows which match.
E.g. give my all Person entities where their age is > 30 and their favorite color is blue or orange. Given that those key/value pairs are stored in a JSON blob, you can find those matched using the example code below.
JSON-search classes and example repo
Classes below use Lombok for brevity.
Classes to allow specification of search criteria
SearchCriteriaContainer
#Data
#EqualsAndHashCode
public class SearchCriteriaContainer
{
private List<SearchCriterion> criteria;
private boolean and;
}
SearchCriterion
#Data
#EqualsAndHashCode(callSuper = true)
public class SearchCriterion extends SearchCriteriaContainer
{
private String field;
private List<String> values;
private SearchOperator operator;
private boolean not = false;
}
SearchOperator
#RequiredArgsConstructor
public enum SearchOperator
{
EQUAL("="),
LESS_THAN("<"),
LESS_THAN_OR_EQUAL("<="),
GREATER_THAN(">"),
GREATER_THAN_OR_EQUAL(">="),
LIKE("like"),
IN("in"),
IS_NULL("is null");
private final String value;
#JsonCreator
public static SearchOperator fromValue(#NotBlank String value)
{
return Stream
.of(SearchOperator.values())
.filter(o -> o.getValue().equals(value))
.findFirst()
.orElseThrow(() ->
{
String message = String.format("Could not find %s with value: %s", SearchOperator.class.getName(), value);
return new IllegalArgumentException(message);
});
}
#JsonValue
public String getValue()
{
return this.value;
}
#Override
public String toString()
{
return value;
}
}
Helper class which is used to call JSON functions
#RequiredArgsConstructor
public class CriteriaBuilderHelper
{
private final CriteriaBuilder criteriaBuilder;
public Expression<String> concat(Expression<?>... values)
{
return criteriaBuilder.function("CONCAT", String.class, values);
}
public Expression<String> substringIndex(Expression<?> value, String delimiter, int count)
{
return substringIndex(value, criteriaBuilder.literal(delimiter), criteriaBuilder.literal(count));
}
public Expression<String> substringIndex(Expression<?> value, Expression<String> delimiter, Expression<Integer> count)
{
return criteriaBuilder.function("SUBSTRING_INDEX", String.class, value, delimiter, count);
}
public Expression<String> jsonUnquote(Expression<?> jsonValue)
{
return criteriaBuilder.function("JSON_UNQUOTE", String.class, jsonValue);
}
public Expression<String> jsonExtract(Expression<?> jsonDoc, Expression<?> path)
{
return criteriaBuilder.function("JSON_EXTRACT", String.class, jsonDoc, path);
}
public Expression<String> jsonSearchOne(Expression<?> jsonDoc, Expression<?> value, Expression<?>... paths)
{
return jsonSearch(jsonDoc, "one", value, paths);
}
public Expression<String> jsonSearch(Expression<?> jsonDoc, Expression<?> value, Expression<?>... paths)
{
return jsonSearch(jsonDoc, "all", value, paths);
}
public Expression<String> jsonSearch(Expression<?> jsonDoc, String oneOrAll, Expression<?> value, Expression<?>... paths)
{
if (!"one".equals(oneOrAll) && !"all".equals(oneOrAll))
{
throw new RuntimeException("Parameter 'oneOrAll' must be 'one' or 'all', not: " + oneOrAll);
}
else
{
final var expressions = new ArrayList<>(List.of(
jsonDoc,
criteriaBuilder.literal(oneOrAll),
value,
criteriaBuilder.nullLiteral(String.class)));
if (paths != null)
{
expressions.addAll(Arrays.asList(paths));
}
return criteriaBuilder.function("JSON_SEARCH", String.class, expressions.toArray(Expression[]::new));
}
}
}
Utility to turn SearchCriteria into MySQL JSON function calls
SearchHelper
public class SearchHelper
{
private static final Pattern pathSeparatorPattern = Pattern.compile("\\.");
public static String getKeyPart(String key)
{
return pathSeparatorPattern.split(key)[0];
}
public static String getPathPart(String key)
{
final var parts = pathSeparatorPattern.split(key);
final var path = new StringBuilder();
for (var i = 1; i < parts.length; i++)
{
if (i > 1)
{
path.append(".");
}
path.append(parts[i]);
}
return path.toString();
}
public static Optional<Predicate> getCriteriaPredicate(SearchCriteriaContainer container, CriteriaBuilder cb, Path<String> bioDetailJson, Path<String> personJson)
{
final var predicates = new ArrayList<Predicate>();
if (container != null && container.getCriteria() != null && container.getCriteria().size() > 0)
{
final var h = new CriteriaBuilderHelper(cb);
container.getCriteria().forEach(ac ->
{
final var groupingOnly = ac.getField() == null && ac.getOperator() == null;
// a criterion can be used for grouping other criterion, and might not have a field/operator/value
if (!groupingOnly)
{
final var key = getKeyPart(ac.getField());
final var path = getPathPart(ac.getField());
final var bioDetailQuestionKeyPathEx = h.jsonUnquote(h.jsonSearchOne(bioDetailJson, cb.literal(key), cb.literal("$[*].key")));
final var bioDetailQuestionIdPathEx = h.concat(h.substringIndex(bioDetailQuestionKeyPathEx, ".", 1), cb.literal(".id"));
final var questionIdEx = h.jsonUnquote(h.jsonExtract(bioDetailJson, bioDetailQuestionIdPathEx));
final var answerPathEx = h.substringIndex(h.jsonUnquote(h.jsonSearchOne(personJson, questionIdEx, cb.literal("$[*].questionId"))), ".", 1);
final var answerValuePathEx = h.concat(answerPathEx, cb.literal("." + path));
final var answerValueEx = h.jsonUnquote(h.jsonExtract(personJson, answerValuePathEx));
switch (ac.getOperator())
{
case IN:
{
final var inEx = cb.in(answerValueEx);
if (ac.getValues() == null || ac.getValues().size() == 0)
{
throw new RuntimeException("No values provided for 'IN' criteria for field: " + ac.getField());
}
else
{
ac.getValues().forEach(inEx::value);
}
predicates.add(inEx);
break;
}
case IS_NULL:
{
predicates.add(cb.isNull(answerValueEx));
break;
}
default:
{
if (ac.getValues() == null || ac.getValues().size() == 0)
{
throw new RuntimeException("No values provided for '" + ac.getOperator() + "' criteria for field: " + ac.getField());
}
else
{
ac.getValues().forEach(value ->
{
final var valueEx = cb.literal(value);
switch (ac.getOperator())
{
case EQUAL:
{
predicates.add(cb.equal(answerValueEx, valueEx));
break;
}
case LESS_THAN:
{
predicates.add(cb.lessThan(answerValueEx, valueEx));
break;
}
case LESS_THAN_OR_EQUAL:
{
predicates.add(cb.lessThanOrEqualTo(answerValueEx, valueEx));
break;
}
case GREATER_THAN:
{
predicates.add(cb.greaterThan(answerValueEx, valueEx));
break;
}
case GREATER_THAN_OR_EQUAL:
{
predicates.add(cb.greaterThanOrEqualTo(answerValueEx, valueEx));
break;
}
case LIKE:
{
predicates.add(cb.like(answerValueEx, valueEx));
break;
}
default:
throw new RuntimeException("Unsupported operator during snapshot search: " + ac.getOperator());
}
});
}
}
}
}
// iterate nested criteria
getAnswerCriteriaPredicate(ac, cb, bioDetailJson, personJson).ifPresent(predicates::add);
});
return Optional.of(container.isAnd()
? cb.and(predicates.toArray(Predicate[]::new))
: cb.or(predicates.toArray(Predicate[]::new)));
}
else
{
return Optional.empty();
}
}
}
Example JPA Specification repository / search method
ExampleRepository
#Repository
public interface PersonRepository extends JpaSpecificationExecutor<Person>
{
default Page<Person> search(PersonSearchDirective directive, Pageable pageable)
{
return findAll((person, query, cb) ->
{
final var bioDetail = person.join(Person_.bioDetail);
final var bioDetailJson = bioDetail.get(BioDetailEntity_.bioDetailJson);
final var personJson = person.get(Person_.personJson);
final var predicates = new ArrayList<>();
SearchHelper
.getCriteriaPredicate(directive.getSearchCriteria(), cb, bioDetailJson, personJson)
.ifPresent(predicates::add);
return cb.and(predicates.toArray(Predicate[]::new));
}, pageable);
}
}
newbie here... i was developing app that send my data to api via retrofit. my code was working but it sends 1 data input only at the time.... in my case, i've like to do is I want to get more saved data in my sqlite (example 5 data saved) and send it all on api via json object.
This is my Activity:
DatabaseHelper databaseHelper2 = new
DatabaseHelper(getApplicationContext());
SQLiteDatabase db2 =
databaseHelper2.getWritableDatabase();
Cursor cursor =
databaseHelper2.retrieveSettingFromLocalDatabase(db2);
while (cursor.moveToNext()) {
ADDRESS =
cursor.getString(cursor.getColumnIndex(DatabaseHelper.SETTING_ADDRESS));
PORT =
cursor.getString(cursor.getColumnIndex(DatabaseHelper.SETTING_PORT));
TIMEINTERVAL=cursor.getString
(cursor.getColumnIndex(DatabaseHelper.SETTING_TIME_INTERVAL));
}
portInts=Integer.parseInt(PORT);
MapDetails mapDetails = new MapDetails(gg, lat, lon,
well, "0", portInts); //Datas ive get to send in api
List<MapDetails> data = new ArrayList<>();
data.add(mapDetails);
Retrofit.Builder builder = new Retrofit.Builder()
.baseUrl("http://" + ADDRESS + ":" + PORT)
.addConverterFactory(GsonConverterFactory.create());
Retrofit retrofit = builder.build();
Api locate = retrofit.create(Api.class);
Call<MapDetails> call = locate.mapDetailLocation(data);
call.enqueue(new Callback<MapDetails>() {
#Override
public void onResponse(Call<MapDetails> call, Response<MapDetails> response) {
Snackbar.make(view, "" + response,
Snackbar.LENGTH_INDEFINITE)
.setAction("Action", null).show();
}
#Override
public void onFailure(Call call, Throwable t) {
Snackbar.make(view, "" + t.getMessage(),
Snackbar.LENGTH_INDEFINITE)
.setAction("Action", null).show();
}
});
This is my code in API:
public interface Api {
#POST("/api/Database/NewLocation")
Call<MapDetails> mapDetailLocation(#Body List<MapDetails> mapDetails)
}
This is my sample Client:
public class MapDetails {
#SerializedName("SerialNumber")
#Expose
private String SerialNumber;
#SerializedName("Coordinate1")
#Expose
private String Coordinate1;
#SerializedName("Coordinate2")
#Expose
private String Coordinate2;
#SerializedName("DateTime")
#Expose
private String DateTime;
#SerializedName("Speed")
#Expose
private String Speed;
#SerializedName("Port")
#Expose
private int Port;
public MapDetails(String serialNumber, String coordinate1, String
coordinate2, String dateTime, String speed, int port) {
SerialNumber = serialNumber;
Coordinate1 = coordinate1;
Coordinate2 = coordinate2;
DateTime = dateTime;
Speed = speed;
Port = port;
}
public String getSerialNumber() {
return SerialNumber;
}
public void setSerialNumber(String serialNumber) {
SerialNumber = serialNumber;
}
public String getCoordinate1() {
return Coordinate1;
}
public void setCoordinate1(String coordinate1) {
Coordinate1 = coordinate1;
}
public String getCoordinate2() {
return Coordinate2;
}
public void setCoordinate2(String coordinate2) {
Coordinate2 = coordinate2;
}
public String getDateTime() {
return DateTime;
}
public void setDateTime(String dateTime) {
DateTime = dateTime;
}
public String getSpeed() {
return Speed;
}
public void setSpeed(String speed) {
Speed = speed;
}
public int getPort() {
return Port;
}
public void setPort(int port) {
Port = port;
}
}
this is my sqlite database ive like to retrieve:
this is the sample posting ive created at the top
but in my case, ive like to do is this one, getting the saved data from my database and send it like this,:
The reason why only one is being sent is that you are sending outside of the while loop that traverses the Cursor, so only the last is sent.
That is you have :-
while (cursor.moveToNext()) {
ADDRESS = cursor.getString(cursor.getColumnIndex(DatabaseHelper.SETTING_ADDRESS));
PORT = cursor.getString(cursor.getColumnIndex(DatabaseHelper.SETTING_PORT));
TIMEINTERVAL=cursor.getString(cursor.getColumnIndex(DatabaseHelper.SETTING_TIME_INTERVAL));
}
So say the query extracted a Cursor with 10 rows as address 1,2,3....10 (for explantory purposes) then
The loop is entered ADDRESS is set to 1, the next iteration sets it to 2, the next to 3 ..... and finally ADDRESS is set to 10 (same for PORT and TIMEINTERVAL)
After the loop the data is sent so only one is sent (ADDRESS 10).
What you need is along the lines of :-
List<MapDetails> data = new ArrayList<>();
MapDetails mapDetails
Retrofit.Builder builder;
Retrofit retrofit;
Call<MapDetails> call;
Api locate;
while (cursor.moveToNext()) {
ADDRESS = cursor.getString(cursor.getColumnIndex(DatabaseHelper.SETTING_ADDRESS));
PORT = cursor.getString(cursor.getColumnIndex(DatabaseHelper.SETTING_PORT));
TIMEINTERVAL=cursor.getString(cursor.getColumnIndex(DatabaseHelper.SETTING_TIME_INTERVAL));
portInts=Integer.parseInt(PORT);
mapDetails = new MapDetails(gg, lat, lon, well, "0", portInts);
data.clear(); //<<<<<<<< remove previous entries if required????
data.add(mapDetails);
builder = new Retrofit.Builder()
.baseUrl("http://" + ADDRESS + ":" + PORT)
.addConverterFactory(GsonConverterFactory.create());
retrofit = builder.build();
locate = retrofit.create(Api.class);
call = locate.mapDetailLocation(data);
call.enqueue(new Callback<MapDetails>() {
#Override
public void onResponse(Call<MapDetails> call, Response<MapDetails> response) {
Snackbar.make(view, "" + response,
Snackbar.LENGTH_INDEFINITE).setAction("Action", null).show();
}
#Override
public void onFailure(Call call, Throwable t) {
Snackbar.make(view, "" + t.getMessage(),
Snackbar.LENGTH_INDEFINITE).setAction("Action", null).show();
}
}
Note the above is in-principle code. it has not been checked or tested and may therefore contain some errors.
It may be that you can send an entire set e.g. data with populated in which case you may only need up to data.add(mapDetails); in the loop and then have the following code outside the loop.
If I understood your question properly, you need to send JSONArray as payload for the request. But, you made a little mistake while preparing payload from SQLite database. #Mike T pointed out that mistake in his answer to your question.
Follow these codes to fix the problem.
DatabaseHelper databaseHelper2 = new DatabaseHelper(getApplicationContext());
SQLiteDatabase db2 = databaseHelper2.getWritableDatabase();
Cursor cursor = databaseHelper2.retrieveSettingFromLocalDatabase(db2);
List<MapDetails> data = new ArrayList<>(); // declare ArrayList outside and before while loop
while (cursor.moveToNext()) {
ADDRESS = cursor.getString(cursor.getColumnIndex(DatabaseHelper.SETTING_ADDRESS));
PORT = cursor.getString(cursor.getColumnIndex(DatabaseHelper.SETTING_PORT));
TIMEINTERVAL = cursor.getString(cursor.getColumnIndex(DatabaseHelper.SETTING_TIME_INTERVAL));
// pass arguments to MapDetails class constructor
portInts = Integer.parseInt(PORT);
MapDetails mapDetails = new MapDetails(gg, lat, lon, well, "0", portInts); //Datas ive get to send in api
// add prepared data to ArrayList
data.add(mapDetails);
}
// and finally execute network call
Retrofit.Builder builder = new Retrofit.Builder()
.baseUrl("http://" + ADDRESS + ":" + PORT)
.addConverterFactory(GsonConverterFactory.create());
Retrofit retrofit = builder.build();
Api locate = retrofit.create(Api.class);
Call<MapDetails> call = locate.mapDetailLocation(data);
call.enqueue(new Callback<MapDetails>() {
#Override
public void onResponse(Call<MapDetails> call, Response<MapDetails> response) {
Snackbar.make(view, "" + response, Snackbar.LENGTH_INDEFINITE).setAction("Action", null).show();
}
#Override
public void onFailure(Call call, Throwable t) {
Snackbar.make(view, "" + t.getMessage(), Snackbar.LENGTH_INDEFINITE).setAction("Action", null).show();
}
});
PS: I'm not sure why are you taking ADDRESS and PORT from SQLite database. If they're same in every single row you don't need to take it from database right?
#JsonFormat(shape = JsonFormat.Shape.STRING, pattern ="yyyy-MM-dd'T'HH:mm:ss.SSS")
is it possible to write regex in pattern? I could not
pattern ="yyyy-MM-dd'T'HH:mm:ss.SSS(Z?)"
I want to make Z as optional
any links suggestions?
I ended up creating custom deserializer based on LocalDateDeserializer.INSTANCE and moved the regex there.
After registering the deserializer the object mapper as a custom module the #JsonFormat annotation is no longer required:
#Bean
public ObjectMapper createObjectMapper() {
return new ObjectMapper()
.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false)
.registerModule(new JavaTimeModule())
.registerModule(new CustomTimeModule());
}
and defined the deserializer in the CustomTimeModule
class CustomTimeModule extends SimpleModule {
public CustomTimeModule() {
super();
addDeserializer(LocalDate.class, CustomLocalDateDeserializer.INSTANCE);
}
}
and finally the regex part, in my case was cutting of the optional non-standard time zone that i was sometimes getting after the date, but could be easily extended to match your case:
public class CustomLocalDateDeserializer extends JSR310DateTimeDeserializerBase<LocalDate> {
private static final long serialVersionUID = 1L;
private static final DateTimeFormatter DEFAULT_FORMATTER = DateTimeFormatter.ISO_LOCAL_DATE;
public static final CustomLocalDateDeserializer INSTANCE = new CustomLocalDateDeserializer();
private CustomLocalDateDeserializer() {
this(DEFAULT_FORMATTER);
}
public CustomLocalDateDeserializer(DateTimeFormatter dtf) {
super(LocalDate.class, dtf);
}
#Override
protected JsonDeserializer<LocalDate> withDateFormat(DateTimeFormatter dtf) {
return new CustomLocalDateDeserializer(dtf);
}
#Override
public LocalDate deserialize(JsonParser parser, DeserializationContext context) throws IOException
{
if (parser.hasToken(JsonToken.VALUE_STRING)) {
String string = parser.getText().trim();
if (string.length() == 0) {
return null;
}
// >>>>>>> regex part comes here <<<<<<<
string = parser.getText().trim().substring(0, 10);
// >>>>>>> regex part comes here <<<<<<<
// as per [datatype-jsr310#37], only check for optional (and, incorrect...) time marker 'T'
// if we are using default formatter
try {
return LocalDate.parse(string, _formatter);
} catch (DateTimeException e) {
return _handleDateTimeException(context, e, string);
}
}
if (parser.isExpectedStartArrayToken()) {
JsonToken t = parser.nextToken();
if (t == JsonToken.END_ARRAY) {
return null;
}
if (context.isEnabled(DeserializationFeature.UNWRAP_SINGLE_VALUE_ARRAYS)
&& (t == JsonToken.VALUE_STRING || t==JsonToken.VALUE_EMBEDDED_OBJECT)) {
final LocalDate parsed = deserialize(parser, context);
if (parser.nextToken() != JsonToken.END_ARRAY) {
handleMissingEndArrayForSingle(parser, context);
}
return parsed;
}
if (t == JsonToken.VALUE_NUMBER_INT) {
int year = parser.getIntValue();
int month = parser.nextIntValue(-1);
int day = parser.nextIntValue(-1);
if (parser.nextToken() != JsonToken.END_ARRAY) {
throw context.wrongTokenException(parser, handledType(), JsonToken.END_ARRAY,
"Expected array to end");
}
return LocalDate.of(year, month, day);
}
context.reportInputMismatch(handledType(),
"Unexpected token (%s) within Array, expected VALUE_NUMBER_INT",
t);
}
if (parser.hasToken(JsonToken.VALUE_EMBEDDED_OBJECT)) {
return (LocalDate) parser.getEmbeddedObject();
}
// 06-Jan-2018, tatu: Is this actually safe? Do users expect such coercion?
if (parser.hasToken(JsonToken.VALUE_NUMBER_INT)) {
return LocalDate.ofEpochDay(parser.getLongValue());
}
return _handleUnexpectedToken(context, parser, "Expected array or string.");
}
I have some JSON coming in (I don't have any control or ability to change the structure and/or naming within the JSON...important to keep in mind in this question) that has a "flat" structure similar to this:
{
"name": "...",
"email": "...",
"box_background_color": "...",
"box_border_color": "...",
"box_text_color": "...",
...
}
Now, I can just create a simple object that keeps everything flat, like so:
public class Settings {
#SerializedName("name")
private String _name;
#SerializedName("email")
private String _emailAddress;
#SerializedName("box_background_color")
private String _boxBackgroundColor;
#SerializedName("box_border_color")
private String _boxBorderColor;
#SerializedName("box_text_color")
private String _boxTextColor;
...
}
However, I want everything associated with box settings to be in it's own class (BoxSettings). This is more like what I want:
public class Settings {
#SerializedName("name")
private String _name;
#SerializedName("email")
private String _emailAddress;
private BoxSettings _boxSettings
...
}
public class BoxSettings {
#SerializedName("box_background_color")
private String _boxBackgroundColor;
#SerializedName("box_border_color")
private String _boxBorderColor;
#SerializedName("box_text_color")
private String _boxTextColor;
...
}
I know that if the JSON was structured such that the box settings were nested then it would be easy to accomplish what I want, however, I don't have the ability to change the structure of the JSON, so please don't suggest that (I would do it if I could).
My question is this: Is creating an entire TypeAdapter the only way to accomplish what I want or can I still accomplish most of this with annotations? If it is not the only way, how else can I accomplish this without changing the JSON at all?
The following is an example of what I mean by "creating an entire TypeAdapter":
public class SettingsTypeAdapter implements JsonDeserializer<Settings>, JsonSerializer<Settings> {
#Override
public JsonElement serialize(Settings src, Type typeOfSrc, JsonSerializationContext context) {
// Add _name
// Add _emailAddress
// Add BoxSettings._boxBackgroundColor
// Add BoxSettings._boxBorderColor
// Add BoxSettings._boxTextColor
return jsonElement;
}
#Override
public Settings deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) throws JsonParseException {
// Read _name
// Read _emailAddress
// Read BoxSettings._boxBackgroundColor
// Read BoxSettings._boxBorderColor
// Read BoxSettings._boxTextColor
return settings;
}
}
The TypeAdapter is not the only way, but in this case would be the best way since you can associate the adapter with a Gson instance (or whatever library you are using) and have all your mapping code there.
Another way is to use JAVA reflection. I've used a version of the below code in my projects before but never with JSON and never with nested objects (mostly when there was no other choice or if i wanted to map a SQL result set to a Java object without calling resultSet.get... a lot of times).
This will work in this case.
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.lang.reflect.Field;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import org.json.JSONObject;
public class Main {
public static void main(String[] args) {
try {
String json = "{\"name\": \"test name\", \"email\": \"email#email.com\", \"box_background_color\": \"red\", \"box_border_color\": \"orange\", \"box_text_color\": \"white\", \"test3_var2\":3}";
JSONObject jsonObject = new JSONObject(json);
System.out.println(jsonObject);
System.out.println();
/*
* need to parse JSON into a map of String, Object
*/
Map<String, Object> mapAll = new HashMap<String, Object>();
Iterator<String> iter = jsonObject.keys();
while (iter.hasNext()) {
String key = (String) iter.next();
Object value = jsonObject.get(key);
mapAll.put(key, value);
System.out.println(key + "::::" + value);
}
System.out.println();
/*
* use the mapper to generate the objects
*/
MyMapper<TestClass1> myMapper = new MyMapper<TestClass1>();
TestClass1 result = myMapper.mapToObject(mapAll, TestClass1.class);
System.out.println(result);
} catch (Exception e) {
e.printStackTrace();
}
}
}
class MyMapper<T> {
#SuppressWarnings("unchecked")
public T mapToObject(Map<String, Object> flatStructure, Class<T> objectClass) {
T result = null;
Field[] fields = null;
try {
// new base object
result = objectClass.newInstance();
// get all of its fields
fields = objectClass.getDeclaredFields();
for (Field field : fields) {
// normal variable
if (field.isAnnotationPresent(MyColumn.class)) {
String variableKey = field.getAnnotation(MyColumn.class).variableKey();
setJavaFieldValue(result, field.getName(), flatStructure.get(variableKey));
}
// variable that is an object and itself has to be mapped
else if (field.isAnnotationPresent(MyInnerColumn.class)) {
String startsWith = field.getAnnotation(MyInnerColumn.class).startsWith();
// reduce the map to only have attributes that are related to this field
Map<String, Object> reducedMap = reduceMap(startsWith, flatStructure);
// make sure that there are attributes for the inner object
if (reducedMap != null) {
// map the inner object
MyMapper<T> myMapper = new MyMapper<T>();
T t2 = myMapper.mapToObject(reducedMap, (Class<T>) field.getType());
// set the mapped object to the base objecct
setJavaFieldValue(result, field.getName(), t2);
}
} else {
// no annotation on the field so ignored
}
}
} catch (Exception e) {
e.printStackTrace();
}
return result;
}
private Map<String, Object> reduceMap(String startsWith, Map<String, Object> mapToReduce) {
Map<String, Object> result = new HashMap<String, Object>();
for (Map.Entry<String, Object> entry : mapToReduce.entrySet()) {
if (entry.getKey().toLowerCase().startsWith(startsWith.toLowerCase())) {
result.put(entry.getKey(), entry.getValue());
}
}
return result.size() == 0 ? null : result;
}
private void setJavaFieldValue(Object object, String fieldName, Object fieldValue) {
try {
Field field = object.getClass().getDeclaredField(fieldName);
boolean fieldAccess = field.isAccessible();
// make the field accessible
field.setAccessible(true);
field.set(object, fieldValue);
// put it back to the way it was
field.setAccessible(fieldAccess);
} catch (Exception e) {
e.printStackTrace();
}
}
}
/*
* Annotation for a regular variable / field
*/
#Target(ElementType.FIELD)
#Retention(RetentionPolicy.RUNTIME)
#interface MyColumn {
// the variable's JSON key
String variableKey() default "";
}
/*
* Annotation for an inner / nested variable / field
*/
#Target(ElementType.FIELD)
#Retention(RetentionPolicy.RUNTIME)
#interface MyInnerColumn {
/*
* JSON keys that start with this string will be
* associated with this nested field
*/
String startsWith() default "";
}
class TestClass1 {
#MyColumn(variableKey = "name")
private String _name;
#MyColumn(variableKey = "email")
private String _emailAddress;
#MyInnerColumn(startsWith = "box_")
private TestClass2 innerClass;
#MyInnerColumn(startsWith = "test3_")
private TestClass3 innerClass2;
#Override
public String toString() {
return "TestClass1 [_name=" + _name + ", _emailAddress=" + _emailAddress + ", innerClass=" + innerClass + ", innerClass2=" + innerClass2 + "]";
}
}
class TestClass2 {
#MyColumn(variableKey = "box_background_color")
private String _boxBackgroundColor;
#MyColumn(variableKey = "box_border_color")
private String _boxBorderColor;
#MyColumn(variableKey = "box_text_color")
private String _boxTextColor;
#Override
public String toString() {
return "TestClass2 [_boxBackgroundColor=" + _boxBackgroundColor + ", _boxBorderColor=" + _boxBorderColor
+ ", _boxTextColor=" + _boxTextColor + "]";
}
}
class TestClass3 {
#MyColumn(variableKey = "test3_var1")
private String _test3Var1;
#MyColumn(variableKey = "test3_var2")
private int _test3Var2;
#Override
public String toString() {
return "TestClass3 [_test3Var1=" + _test3Var1 + ", _test3Var2=" + _test3Var2 + "]";
}
}
Output
{"box_background_color":"red","box_text_color":"white","test3_var2":3,"name":"test name","email":"email#email.com","box_border_color":"orange"}
box_background_color::::red
box_text_color::::white
test3_var2::::3
name::::test name
email::::email#email.com
box_border_color::::orange
TestClass1 [_name=test name, _emailAddress=email#email.com, innerClass=TestClass2 [_boxBackgroundColor=red, _boxBorderColor=orange, _boxTextColor=white], innerClass2=TestClass3 [_test3Var1=null, _test3Var2=3]]
I'm trying with a Struts jQuery grid using the struts2-jquery-grid-3.7.0 plugin as demonstrated on the showcase, Grid (Editable/Multiselect).
The Struts form:
<s:form namespace="/admin_side" action="Test" validate="true" id="dataForm" name="dataForm">
<s:url id="remoteurl" action="TestGrid" namespace="/admin_side"/>
<s:url id="editurl" action="edit-grid-entry"/>
<sjg:grid
id="gridmultitable"
caption="Example (Editable/Multiselect)"
dataType="json"
href="%{remoteurl}"
pager="true"
navigator="true"
navigatorSearchOptions="{sopt:['eq','ne','lt','gt']}"
navigatorAddOptions="{height:280, width:500, reloadAfterSubmit:true}"
navigatorEditOptions="{height:280, width:500, reloadAfterSubmit:false}"
navigatorEdit="true"
navigatorView="true"
navigatorViewOptions="{height:280, width:500}"
navigatorDelete="true"
navigatorDeleteOptions="{height:280, width:500,reloadAfterSubmit:true}"
gridModel="gridModel"
rowList="5,10,15"
rowNum="5"
rownumbers="true"
editurl="%{editurl}"
editinline="true"
multiselect="true"
onSelectRowTopics="rowselect"
>
<sjg:gridColumn name="countryId" index="countryId" title="Id" formatter="integer" editable="false" sortable="true" search="true" sorttype="integer" searchoptions="{sopt:['eq','ne','lt','gt']}"/>
<sjg:gridColumn name="countryName" index="countryName" title="Country Name" editable="true" edittype="text" sortable="true" search="true" sorttype="text"/>
<sjg:gridColumn name="countryCode" index="countryCode" title="Country Code" sortable="true" search="true" editable="true" sorttype="text"/>
</sjg:grid>
</s:form>
The action class:
#Namespace("/admin_side")
#ResultPath("/WEB-INF/content")
#ParentPackage(value = "json-default")
#InterceptorRefs(#InterceptorRef(value = "store", params = {"operationMode", "AUTOMATIC"}))
public final class TestAction extends ActionSupport implements Serializable
{
#Autowired
private final transient CountryService countryService=null;
private static final long serialVersionUID = 1L;
// Result List
private List<Country> gridModel;
// Get how many rows we want to have into the grid - rowNum attribute in the grid
private Integer rows=5;
// Get the requested page. By default grid sets this to 1.
private Integer page=1;
// sorting order - asc or desc
private String sord;
// get index row - i.e. user click to sort.
private String sidx;
// Search Field
private String searchField;
// The Search String
private String searchString;
// The Search Operation ['eq','ne','lt','le','gt','ge','bw','bn','in','ni','ew','en','cn','nc']
private String searchOper;
// Your Total Pages
private Integer total;
// All Records
private Integer records;
#Action(value = "TestGrid",
results = {
#Result(name = ActionSupport.SUCCESS, type = "json", params = {"includeProperties", "gridModel\\[\\d+\\]\\.countryId, gridModel\\[\\d+\\]\\.countryName, gridModel\\[\\d+\\]\\.countryCode", "excludeNullProperties", "true"})},
interceptorRefs = {
#InterceptorRef(value = "json")})
public String execute() {
records=countryService.rowCount().intValue();
total=new BigDecimal(records).divide(new BigDecimal(rows), 0, BigDecimal.ROUND_CEILING).intValue();
gridModel=countryService.getList(page, rows, null, null);
System.out.println("records "+records+" total "+total+" Page " + getPage() + " Rows " + getRows() + " Sort Order " + getSord() + " Index Row :" + getSidx()+"Search :" + searchField + " " + searchOper + " " + searchString);
return SUCCESS;
}
public String getJSON() {
return execute();
}
public Integer getRows() {
return rows;
}
public void setRows(Integer rows) {
this.rows = rows;
}
public Integer getPage() {
return page;
}
public void setPage(Integer page) {
this.page = page;
}
public Integer getTotal() {
return total;
}
public void setTotal(Integer total) {
this.total = total;
}
public Integer getRecords() {
return records;
}
public void setRecords(Integer records) {
this.records = records;
}
public List<Country> getGridModel() {
return gridModel;
}
public void setGridModel(List<Country> gridModel) {
this.gridModel = gridModel;
}
public String getSord() {
return sord;
}
public void setSord(String sord) {
this.sord = sord;
}
public String getSidx() {
return sidx;
}
public void setSidx(String sidx) {
this.sidx = sidx;
}
public void setSearchField(String searchField) {
this.searchField = searchField;
}
public void setSearchString(String searchString) {
this.searchString = searchString;
}
public void setSearchOper(String searchOper) {
this.searchOper = searchOper;
}
#Action(value = "Test",
results = {
#Result(name = ActionSupport.SUCCESS, location = "Test.jsp"),
#Result(name = ActionSupport.INPUT, location = "Test.jsp")},
interceptorRefs = {
#InterceptorRef(value = "defaultStack", params = {"validation.validateAnnotatedMethodOnly", "true", "validation.excludeMethods", "load"})})
public String load() throws Exception {
return ActionSupport.SUCCESS;
}
}
The next and previous pagination links are always disabled as shown in the following snap shot.
It indicates, page 1 of 1. There are no more pages. Hence, the links are disabled.
In the execute() method, however, records is initialized to 31, total to 7 Page to 1 Rows to 5. All other properties are always null whether or not links/buttons for sorting, searching, editing, adding a row are clicked.
What am I overlooking here?
You forgot to include fields to json result that are necessary for grid to function properly. Change to
#Result(type = "json", params = {"includeProperties", "gridModel\\[\\d+\\]\\.countryId, gridModel\\[\\d+\\]\\.countryName, gridModel\\[\\d+\\]\\.countryCode, total, records, rows, page, sord, sidx, searchField, searchString, searchOper", "excludeNullProperties", "true"})
Also, json interceptor is not necessary, but params is required.
#InterceptorRef("params")