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How to save and load Objects to and from a file

I'm gonna be honest I am panicking. I am doing an exam in a Java course and I have been stuck for some time now.
I have to implement a RSS Feader and I am currently doing methods to save and load subscribed feeds. I thought I got the saveSubscribedFeeds method right because it passes the JUnit Test but I am starting to think I have some kind of error in there so that the loadSubscribeFeeds method cannot work properly.
Here is the saveSubscribedFeeds method:
public void saveSubscribedFeeds(List<Feed> feeds, File feedsFile) {
FileWriter writer = null;
try {
writer = new FileWriter(feedsFile);
for(Feed f: feeds) {
writer.write(f + System.lineSeparator());
}
writer.close();
} catch (IOException e) {
e.getMessage();
}
}
For the loadSubscribedFeed method I already tried a Scanner, BufferedReader and FileInputStream and ObjectInputStream but nothing works. This is my current method:
public List<Feed> loadSubscribedFeeds(File feedsFile) {
Scanner s = null;
try {
s = new Scanner(feedsFile);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
List<String> listString = new ArrayList<>();
List<Feed> listFeed = new ArrayList<>();
while (s.hasNextLine()) {
listString.add(s.nextLine());
}
for(String f : listString) {
listFeed.add(new Feed(f));
}
return listFeed;
}
here is also the Feed class:
public class Feed implements Serializable, Comparable<Feed> {
private static final long serialVersionUID = 1L;
private String url;
private String title;
private String description;
private String publishedDateString;
private List<Entry> entries;
public Feed(String url) {
super();
this.url = url;
this.entries = new ArrayList<Entry>();
this.title = "";
this.description = "";
this.publishedDateString = "";
}
/**
* Creates an instance of a Feed and transfers the feed
* data form a SyndFeed object to the new instance.
* #param url The URL string of this feed
* #param sourceFeed The SyndFeed object holding the data for this feed instance
*/
public Feed(String url, SyndFeed sourceFeed) {
this(url);
setTitle(sourceFeed.getTitle());
setDescription(sourceFeed.getDescription());
if (sourceFeed.getPublishedDate() != null)
setPublishedDateString(FeaderUtils.DATE_FORMAT.format(sourceFeed.getPublishedDate()));
for (SyndEntry entryTemp : sourceFeed.getEntries()) {
Entry entry = new Entry(entryTemp.getTitle());
entry.setContent(entryTemp.getDescription().getValue());
entry.setLinkUrl(entryTemp.getLink());
entry.setParentFeedTitle(getTitle());
if (entryTemp.getPublishedDate() != null) {
entry.setPublishedDateString(FeaderUtils.DATE_FORMAT.format(entryTemp.getPublishedDate()));
}
addEntry(entry);
}
}
public String getUrl() {
return url;
}
public void setTitle(String title) {
this.title = title != null ? title : "";
}
public String getTitle() {
return title;
}
public void setDescription(String description) {
this.description = description != null ? description : "";
}
public String getDescription() {
return description;
}
public void setPublishedDateString(String publishedDateString) {
this.publishedDateString = publishedDateString != null ? publishedDateString : "";
}
public String getPublishedDateString() {
return publishedDateString;
}
/**
* Returns a short string containing a combination of meta data for this feed
* #return info string
*/
public String getShortFeedInfo() {
return getTitle() + " [" +
getEntriesCount() + " entries]: " +
getDescription() +
(getPublishedDateString() != null && getPublishedDateString().length() > 0
? " (updated " + getPublishedDateString() + ")"
: "");
}
public void addEntry(Entry entry) {
if (entry != null) entries.add(entry);
}
public List<Entry> getEntries() {
return entries;
}
public int getEntriesCount() {
return entries.size();
}
#Override
public boolean equals(Object obj) {
return (obj instanceof Feed)
&& ((Feed)obj).getUrl().equals(url);
}
#Override
public int hashCode() {
return url.hashCode();
}
#Override
public String toString() {
return getTitle();
}
#Override
public int compareTo(Feed o) {
return getPublishedDateString().compareTo(o.getPublishedDateString());
}
}
Maybe someone out there will be able to help me or guide me in the correct direction.
Thanks already in advance.

Android NetworkBoundResource using repository pattern API error

Hi I am just started with mvvm with repository pattern I am stuck with the API error
I am using the generic API Response class as per google official repo in java
/**
* Generic class for handling responses from Retrofit
*
* #param <T>
*/
public class ApiResponse<T> {
public ApiResponse<T> create(Throwable error) {
return new ApiErrorResponse<>(error.getMessage().equals("") ? error.getMessage() : "Unknown error\nCheck network connection");
}
public ApiResponse<T> create(Response<T> response) {
if (response.isSuccessful()) {
T body = response.body();
if (body instanceof GithubApiResponse) {
if (AppUtils.isValid((GithubApiResponse) body)) {
String errorMsg = "Empty Response.";
return new ApiErrorResponse<>(errorMsg);
}
}
if (body == null || response.code() == 204) { // 204 is empty response
return new ApiEmptyResponse<>();
} else {
return new ApiSuccessResponse<>(body);
}
} else {
String errorMsg = "";
try {
errorMsg = response.errorBody().string();
} catch (IOException e) {
e.printStackTrace();
errorMsg = response.message();
}
return new ApiErrorResponse<>(errorMsg);
}
}
/**
* Generic success response from api
*
* #param <T>
*/
public class ApiSuccessResponse<T> extends ApiResponse<T> {
private T body;
ApiSuccessResponse(T body) {
this.body = body;
}
public T getBody() {
return body;
}
}
/**
* Generic Error response from API
*
* #param <T>
*/
public class ApiErrorResponse<T> extends ApiResponse<T> {
private String errorMessage;
ApiErrorResponse(String errorMessage) {
this.errorMessage = errorMessage;
}
public String getErrorMessage() {
return errorMessage;
}
}
/**
* separate class for HTTP 204 resposes so that we can make ApiSuccessResponse's body non-null.
*/
public class ApiEmptyResponse<T> extends ApiResponse<T> {
}
}
and My networkBoundResource as like this
public abstract class NetworkBoundResource<ResultType, RequestType> {
private AppExecutors appExecutors;
private MediatorLiveData<Resource<ResultType>> results = new MediatorLiveData<>();
public NetworkBoundResource(AppExecutors appExecutors) {
this.appExecutors = appExecutors;
init();
}
private void init() {
// update LiveData for loading status
results.setValue((Resource<ResultType>) Resource.loading(null));
// observe LiveData source from local db
final LiveData<ResultType> dbSource = loadFromDb();
results.addSource(dbSource, new Observer<ResultType>() {
#Override
public void onChanged(#Nullable ResultType ResultType) {
results.removeSource(dbSource);
if (shouldFetch(ResultType)) {
// get data from the network
fetchFromNetwork(dbSource);
} else {
results.addSource(dbSource, new Observer<ResultType>() {
#Override
public void onChanged(#Nullable ResultType ResultType) {
setValue(Resource.success(ResultType));
}
});
}
}
});
}
/**
* 1) observe local db
* 2) if <condition/> query the network
* 3) stop observing the local db
* 4) insert new data into local db
* 5) begin observing local db again to see the refreshed data from network
*
* #param dbSource
*/
private void fetchFromNetwork(final LiveData<ResultType> dbSource) {
Timber.d("fetchFromNetwork: called.");
// update LiveData for loading status
results.addSource(dbSource, new Observer<ResultType>() {
#Override
public void onChanged(#Nullable ResultType ResultType) {
setValue(Resource.loading(ResultType));
}
});
final LiveData<ApiResponse<RequestType>> apiResponse = createCall();
results.addSource(apiResponse, new Observer<ApiResponse<RequestType>>() {
#Override
public void onChanged(#Nullable final ApiResponse<RequestType> requestObjectApiResponse) {
results.removeSource(dbSource);
results.removeSource(apiResponse);
/*
3 cases:
1) ApiSuccessResponse
2) ApiErrorResponse
3) ApiEmptyResponse
*/
if (requestObjectApiResponse instanceof ApiResponse.ApiSuccessResponse) {
Timber.d("onChanged: ApiSuccessResponse.");
appExecutors.diskIO().execute(new Runnable() {
#Override
public void run() {
// save the response to the local db
saveCallResult((RequestType) processResponse((ApiResponse.ApiSuccessResponse) requestObjectApiResponse));
appExecutors.mainThread().execute(new Runnable() {
#Override
public void run() {
results.addSource(loadFromDb(), new Observer<ResultType>() {
#Override
public void onChanged(#Nullable ResultType ResultType) {
setValue(Resource.success(ResultType));
}
});
}
});
}
});
} else if (requestObjectApiResponse instanceof ApiResponse.ApiEmptyResponse) {
Timber.d("onChanged: ApiEmptyResponse");
appExecutors.mainThread().execute(new Runnable() {
#Override
public void run() {
results.addSource(loadFromDb(), new Observer<ResultType>() {
#Override
public void onChanged(#Nullable ResultType ResultType) {
setValue(Resource.success(ResultType));
}
});
}
});
} else if (requestObjectApiResponse instanceof ApiResponse.ApiErrorResponse) {
Timber.d("onChanged: ApiErrorResponse.");
results.addSource(dbSource, new Observer<ResultType>() {
#Override
public void onChanged(#Nullable ResultType ResultType) {
setValue(
Resource.error(
((ApiResponse.ApiErrorResponse) requestObjectApiResponse).getErrorMessage(),
ResultType
)
);
}
});
}
}
});
}
private ResultType processResponse(ApiResponse.ApiSuccessResponse response) {
return (ResultType) response.getBody();
}
private void setValue(Resource<ResultType> newValue) {
if (results.getValue() != newValue) {
results.setValue(newValue);
}
}
// Called to save the result of the API response into the database.
#WorkerThread
protected abstract void saveCallResult(#NonNull RequestType item);
// Called with the data in the database to decide whether to fetch
// potentially updated data from the network.
#MainThread
protected abstract boolean shouldFetch(#Nullable ResultType data);
// Called to get the cached data from the database.
#NonNull
#MainThread
protected abstract LiveData<ResultType> loadFromDb();
// Called to create the API call.
#NonNull
#MainThread
protected abstract LiveData<ApiResponse<RequestType>> createCall();
// Returns a LiveData object that represents the resource that's implemented
// in the base class.
public final LiveData<Resource<ResultType>> getAsLiveData() {
return results;
}
}
my Repository looks like this
#Singleton
public class GithubRepository {
private GithubDao githubDao;
private GithubTrendingApiService githubApiService;
public GithubRepository(GithubDao githubDao, GithubTrendingApiService githubApiService) {
this.githubDao = githubDao;
this.githubApiService = githubApiService;
}
public LiveData<Resource<List<GithubEntity>>> getRepositories() {
return new NetworkBoundResource<List<GithubEntity>, GithubApiResponse>(AppExecutors.getInstance()) {
#Override
protected void saveCallResult(#NonNull GithubApiResponse item) {
List<GithubEntity> repositories = item.getItems();
githubDao.insertRepositories(repositories);
}
#Override
protected boolean shouldFetch(#Nullable List<GithubEntity> data) {
// Timber.d("shouldFetch: repo: " + data.toString());
// int currentTime = (int) (System.currentTimeMillis() / 1000);
// Timber.d("shouldFetch: current time: " + currentTime);
// int lastRefresh = data.getTimestamp();
// Timber.d("shouldFetch: last refresh: " + lastRefresh);
// Timber.d("shouldFetch: it's been " + ((currentTime - lastRefresh) / 60 / 60 / 24) +
// " days since this recipe was refreshed. 30 days must elapse before refreshing. ");
// if ((currentTime - data.getTimestamp()) >= Constants.RECIPE_REFRESH_TIME) {
// Timber.d("shouldFetch: SHOULD REFRESH RECIPE?! " + true);
// return true;
// }
// Timber.d("shouldFetch: SHOULD REFRESH RECIPE?! " + false);
return true;
}
#NonNull
#Override
protected LiveData<List<GithubEntity>> loadFromDb() {
return githubDao.getTrendingRepository();
}
#NonNull
#Override
protected LiveData<ApiResponse<GithubApiResponse>> createCall() {
return githubApiService.fetchTrendingRepositories();
}
}.getAsLiveData();
}
}
Can anyone tell me whats I am doing wrong because I am getting an API error? somehow I am not able to get the correct data that's why the database is also not filling up
my GithubAPi response class is this
public class GithubApiResponse {
public GithubApiResponse() {
this.items = new ArrayList<>();
}
public GithubApiResponse(List<GithubEntity> items) {
this.items = items;
}
private List<GithubEntity> items;
public List<GithubEntity> getItems() {
return items;
}
public void setItems(List<GithubEntity> items) {
this.items = items;
}
}
and the Entity class is this
#Entity
public class GithubEntity implements Parcelable {
public GithubEntity(#NonNull Long id, String author, String name, String avatar,
String url, String description, Integer stars, Integer forks, Integer currentPeriodStars, String language, String languageColor) {
this.id = id;
this.author = author;
this.name = name;
this.avatar = avatar;
this.url = url;
this.description = description;
this.stars = stars;
this.forks = forks;
this.currentPeriodStars = currentPeriodStars;
this.language = language;
this.languageColor = languageColor;
}
#NonNull
#PrimaryKey
private Long id;
#SerializedName("author")
#Expose
private String author;
#SerializedName("name")
#Expose
private String name;
#SerializedName("avatar")
#Expose
private String avatar;
#SerializedName("url")
#Expose
private String url;
#SerializedName("description")
#Expose
private String description;
#SerializedName("stars")
#Expose
private Integer stars;
#SerializedName("forks")
#Expose
private Integer forks;
#SerializedName("currentPeriodStars")
#Expose
private Integer currentPeriodStars;
#SerializedName("language")
#Expose
private String language;
#SerializedName("languageColor")
#Expose
private String languageColor;
#NonNull
public Long getId() {
return id;
}
public void setId(#NonNull Long id) {
this.id = id;
}
protected GithubEntity(Parcel in) {
author = in.readString();
name = in.readString();
avatar = in.readString();
url = in.readString();
description = in.readString();
if (in.readByte() == 0) {
stars = null;
} else {
stars = in.readInt();
}
if (in.readByte() == 0) {
forks = null;
} else {
forks = in.readInt();
}
if (in.readByte() == 0) {
currentPeriodStars = null;
} else {
currentPeriodStars = in.readInt();
}
language = in.readString();
languageColor = in.readString();
}
public static final Creator<GithubEntity> CREATOR = new Creator<GithubEntity>() {
#Override
public GithubEntity createFromParcel(Parcel in) {
return new GithubEntity(in);
}
#Override
public GithubEntity[] newArray(int size) {
return new GithubEntity[size];
}
};
public String getAuthor() {
return author;
}
public void setAuthor(String author) {
this.author = author;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getAvatar() {
return avatar;
}
public void setAvatar(String avatar) {
this.avatar = avatar;
}
public String getUrl() {
return url;
}
public void setUrl(String url) {
this.url = url;
}
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
public Integer getStars() {
return stars;
}
public void setStars(Integer stars) {
this.stars = stars;
}
public Integer getForks() {
return forks;
}
public void setForks(Integer forks) {
this.forks = forks;
}
public Integer getCurrentPeriodStars() {
return currentPeriodStars;
}
public void setCurrentPeriodStars(Integer currentPeriodStars) {
this.currentPeriodStars = currentPeriodStars;
}
public String getLanguage() {
return language;
}
public void setLanguage(String language) {
this.language = language;
}
public String getLanguageColor() {
return languageColor;
}
public void setLanguageColor(String languageColor) {
this.languageColor = languageColor;
}
#Override
public int describeContents() {
return 0;
}
#Override
public void writeToParcel(Parcel dest, int flags) {
dest.writeString(author);
dest.writeString(name);
dest.writeString(avatar);
dest.writeString(url);
dest.writeString(description);
if (stars == null) {
dest.writeByte((byte) 0);
} else {
dest.writeByte((byte) 1);
dest.writeInt(stars);
}
if (forks == null) {
dest.writeByte((byte) 0);
} else {
dest.writeByte((byte) 1);
dest.writeInt(forks);
}
if (currentPeriodStars == null) {
dest.writeByte((byte) 0);
} else {
dest.writeByte((byte) 1);
dest.writeInt(currentPeriodStars);
}
dest.writeString(language);
dest.writeString(languageColor);
}
}
can anyone guide me so that I can fix this issue? stuck here for 2 days

How to group values in list based on id in java?

Hello folks this may be dumb question but as a beginner am struggling with this how to group values based on id in list, Now let me clarify you briefly am having set of objects like this :
ID:1,UserID:330
ID:2,UserID:303
ID:3,UserID:090
ID:1,UserID:302
ID:2,UserID:306
How my list should look like is(Json Format):
[{"ID":1,"UserID":[330,302]},{"ID":2,"UserID":[303,306]},{"ID":3,"UserID":[090]}]
Now let me post what i have tried so far:
final List<Integer>list=new ArrayList<>();
final List<SpareReturnModel>lisobj=new ArrayList<>();
int duplicate=0;
for(int i=0;i<tView.getSelected().size();i++){
Object o= tView.getSelected().get(i).getValue();
SpareReturnModel asset=(SpareReturnModel) o;
int flag=asset.getFlag();
if(flag==2) {
int warehouseid = asset.getWareHouseID();
asset.setWareHouseID(warehouseid);
int partid = asset.getSerialNoID();
list.add(partid);
}
else {
Log.d("s","no value for header");
}
if(duplicate!=asset.getWareHouseID()){
asset.setParlist(list);
asset.setWareHouseID(asset.getWareHouseID());
lisobj.add(asset);
list.clear();
}
duplicate=asset.getWareHouseID();
}
Gson gson=new Gson();
//this will convert list to json
String value=gson.toJson(listobj);
SpareReturn Model Class:
public class SpareReturnModel {
private Integer SerialNoID;
private String SerialNumber;
private List<Integer>parlist;
public List<Integer> getParlist() {
return parlist;
}
public void setParlist(List<Integer> parlist) {
this.parlist = parlist;
}
public Integer getFlag() {
return flag;
}
public void setFlag(Integer flag) {
this.flag = flag;
}
private Integer flag;
public Integer getWareHouseID() {
return WareHouseID;
}
public void setWareHouseID(Integer wareHouseID) {
WareHouseID = wareHouseID;
}
private Integer WareHouseID;
public Integer getSerialNoID() {
return SerialNoID;
}
public void setSerialNoID(Integer serialNoID) {
SerialNoID = serialNoID;
}
public String getSerialNumber() {
return SerialNumber;
}
public void setSerialNumber(String serialNumber) {
SerialNumber = serialNumber;
}
}
Can someone let me know how to achieve this am struggling with this.

I simplify your class to make solution clearer:
public class SpareReturnModel implements Comparable<SpareReturnModel> {
private Integer id;
private String userId;
public SpareReturnModel(Integer id, String userId) {
this.id = id;
this.userId = userId;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getUserId() {
return userId;
}
public void setUserId(String userId) {
this.userId = userId;
}
#Override
public int compareTo(SpareReturnModel other) {
return this.getId().compareTo(other.getId());
}
#Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
SpareReturnModel model = (SpareReturnModel) o;
if (id != null ? !id.equals(model.id) : model.id != null) return false;
return userId != null ? userId.equals(model.userId) : model.userId == null;
}
#Override
public int hashCode() {
int result = id != null ? id.hashCode() : 0;
result = 31 * result + (userId != null ? userId.hashCode() : 0);
return result;
}
}
and add JsonSpareReturnModel
public class JsonSpareRuturnModel implements Comparable<JsonSpareRuturnModel> {
private final List<SpareReturnModel> modelList;
private final Integer id;
public JsonSpareRuturnModel(List<SpareReturnModel> modelList) {
this.modelList = modelList;
this.id = modelList.get(0).getId();
}
private final String toJson() {
return String.format("{\"ID\":%s,\"UserID\":%s}", id, formatUserIdList());
}
private String formatUserIdList() {
StringBuilder builder = new StringBuilder("[");
Iterator<SpareReturnModel> modelIterator = modelList.iterator();
while (modelIterator.hasNext()) {
builder.append(modelIterator.next().getUserId());
if (modelIterator.hasNext()) {
builder.append(",");
}
}
builder.append("]");
return builder.toString();
}
#Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
JsonSpareRuturnModel that = (JsonSpareRuturnModel) o;
return id != null ? id.equals(that.id) : that.id == null;
}
#Override
public int hashCode() {
return id != null ? id.hashCode() : 0;
}
#Override
public int compareTo(JsonSpareRuturnModel other) {
return this.id.compareTo(other.id);
}
#Override
public String toString() {
return toJson();
}
if you need to group by user id you need to sort your models according to id's
and place them to json format model:
public class Main {
public static void main(String[] args) {
List<SpareReturnModel> models = new ArrayList<>(Arrays.asList(
new SpareReturnModel(1, "330"),
new SpareReturnModel(2, "303"),
new SpareReturnModel(3, "090"),
new SpareReturnModel(1, "302"),
new SpareReturnModel(2, "306")
));
Map<Integer, List<SpareReturnModel>> groupById = new HashMap<>();
for (SpareReturnModel model : models) {
List<SpareReturnModel> listById = groupById.get(model.getId());
if (listById == null) {
groupById.put(model.getId(), new ArrayList<>(Arrays.asList(model)));
} else {
listById.add(model);
}
}
List<JsonSpareRuturnModel> jsonList = new ArrayList<>();
for (Map.Entry<Integer, List<SpareReturnModel>> pair : groupById.entrySet()) {
jsonList.add(new JsonSpareRuturnModel(pair.getValue()));
}
System.out.println(jsonList);
final String expected = "[{\"ID\":1,\"UserID\":[330,302]}, {\"ID\":2,\"UserID\":[303,306]}, {\"ID\":3,\"UserID\":[090]}]";
System.out.println(jsonList.toString().equals(expected));
}
}

How to solve StringConverter ClassCast Exception?

I have a TableView and a form with some TextBox and ComboBox in my javafx application. I am trying to populate the form components with selected rows data from TableView. I can populate all the TextBox without any error or exception. But while setting values to ComboBoxes, it's throwing an ClassCastException, java.lang.ClassCastException: java.lang.String cannot be cast to entity.StockUOM.
This is my StringCoverter
unitCombo.setConverter(new StringConverter<StockUOM>() {
#Override
public String toString(StockUOM object) {
return object.getStockUOM();
}
#Override
public StockUOM fromString(String string) {
return null;
}
});
This is my entity.StockUOM class
#Entity
#Access(AccessType.PROPERTY)
#NamedQueries({
#NamedQuery(name = StockUOM.findStockUOM, query = "SELECT s from StockUOM s")
})
public class StockUOM implements Externalizable{
public final static String PREFIX = "entity.StockUOM.";
public final static String findStockUOM = PREFIX + "findStockUOM";
private IntegerProperty id;
private int _id;
private StringProperty stockUOM;
private String _stockUOM;
public StockUOM() {
if (id == null) {
id = new SimpleIntegerProperty(this, "id", _id);
}
if( stockUOM== null){
stockUOM= new SimpleStringProperty(this,"stockUOM",_stockUOM);
}
}
public StockUOM(String stockUOM) {
this();
this.stockUOM.set(stockUOM);
}
public IntegerProperty idProperty() {
if (id == null) {
id = new SimpleIntegerProperty(this, "id", _id);;
}
return id;
}
#Id
#GeneratedValue(strategy=GenerationType.AUTO)
public final int getId() {
if (id == null) {
return _id;
} else {
return id.get();
}
}
public final void setId(int id) {
if (this.id == null) {
_id = id;
} else {
this.id.set(id);
}
}
public StringProperty stockUOMProperty() {
if( stockUOM== null){
stockUOM= new SimpleStringProperty(this,"stockUOM",_stockUOM);
}
return stockUOM;
}
public final String getStockUOM() {
if(stockUOM == null){
return _stockUOM;
}else{
return stockUOM.get();
}
}
public void setStockUOM(String stockUOM) {
if (this.stockUOM == null) {
_stockUOM=stockUOM ;
} else {
this.stockUOM.set(stockUOM);
}
}
#Override
public void writeExternal(ObjectOutput out) throws IOException {
out.writeInt(getId());
out.writeChars(getStockUOM());
}
#Override
public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
setId(in.readInt());
setStockUOM((String)in.readObject());
}
#Override
public String toString() {
return getStockUOM();
}
}
This is how i am setting values to ComboBox
unitCombo.setValue(newValue.getUnit());
Here newValue is the instance of StockUOM of ChangeListner which is listening on TableView row selection.
So what's wrong i am doing ? And what's the solution.
Thanks.

The problem is that most probably you defined your ComboBox like:
ComboBox unitCombo = new ComboBox();
So you missed to define the generic argument and you ended up with the raw type (your IDE most probably gives you a warning on this line).
At this point it is not specified what kind of objects do you want to display in the ComboBox.
When you do the following:
unitCombo.setValue(newValue.getUnit());
you set the valueProperty as a String value.
And then comes your converter:
unitCombo.setConverter(new StringConverter<StockUOM>() {
#Override
public String toString(StockUOM object) {
return object.getStockUOM();
}
#Override
public StockUOM fromString(String string) {
return null;
}
});
which expects StockUOM object being displayed, which does not happen hence the error.
You have to decide what kind of object do you want to display: if it is StockUOM, then declare the ComboBox as ComboBox<StockUOM> unitCombo = new ComboBox<StockUOM>();. After this you will have a compile time error on the line where you set the value for a String value, to fix that error you have to modify that line as unitCombo.setValue(newValue);. If you want to display String objects, the methodology is the same.

Getting null value for xml formatted string after Deserialization

I am a beginner in android.I am calling a webservice from my android project which returns a json string as response which contain a xml formatted string as one entry.
String jsoncontent=restTemplate.getForObject(constr+"getAssetdata/{Id}", String.class, curAcct.getiD());
final GsonBuilder gsonBuilder = new GsonBuilder();
gsonBuilder.registerTypeAdapter(Assets.class, new AssetDeserialiser());
final Gson gson = gsonBuilder.create();
Assets assetAcc = gson.fromJson(jsoncontent, Assets.class);
Toast.makeText(getApplicationContext(), assetAcc.getKeyValueData(), 68000).show();
Below is the json string that i got as webservice response
jsoncontent={"id":39,"name":"ICICI Bank","purchaseValue":6000.0,"purchaseDate":1402403751000,"keyValueData":"<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"no\"?><root><Description><Name>Tax and other payments</Name><Value>433</Value></Description><Description><Name>Add more details...</Name><Value></Value></Description></root>"}
But i am getting a null value for assetAcc.getKeyValueData() after deserialization,there is no isue with other fields in assets.How to solve this issue? Please help me.
AssetDeserialiser.java:
public class AssetDeserialiser implements JsonDeserializer<Assets> {
#Override
public Assets deserialize(JsonElement arg0, Type arg1, JsonDeserializationContext arg2) throws JsonParseException {
JsonObject jobject =arg0.getAsJsonObject();
final Assets asset = new Assets();
try{
asset.setId(jobject.get("id").getAsInt());
asset.setName(jobject.get("name").getAsString());
asset.setPurchaseValue(jobject.get("purchaseValue").getAsFloat());
asset.setPurchaseDate(new Timestamp(jobject.get("purchaseDate").getAsLong()));
asset.setKeyValueData(jobject.get("keyValueData").isJsonNull() ? "" : jobject.get("keyValueData").getAsString());
}catch(Exception es){
System.out.println("es "+es);
}
return asset;
}
}
Assets.java:
public class Assets implements Serializable{
private Integer id;
private String name;
private Float purchaseValue;
private Timestamp purchaseDate;
private String keyValueData;
public Assets() {
super();
// TODO Auto-generated constructor stub
}
public Assets(Integer id, String name, Float purchaseValue, Timestamp purchaseDate, String keyValueData) {
super();
this.id = id;
this.name = name;
this.purchaseValue = purchaseValue;
this.purchaseDate = purchaseDate;
this.keyValueData = keyValueData;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Float getPurchaseValue() {
return purchaseValue;
}
public void setPurchaseValue(Float purchaseValue) {
this.purchaseValue = purchaseValue;
}
public Timestamp getPurchaseDate() {
return purchaseDate;
}
public void setPurchaseDate(Timestamp purchaseDate) {
this.purchaseDate = purchaseDate;
}
public String getKeyValueData() {
return keyValueData;
}
public void setKeyValueData(String keyValueData) {
this.keyValueData = keyValueData;
}
#Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + ((id == null) ? 0 : id.hashCode());
result = prime * result
+ ((keyValueData == null) ? 0 : keyValueData.hashCode());
result = prime * result + ((name == null) ? 0 : name.hashCode());
result = prime * result
+ ((purchaseDate == null) ? 0 : purchaseDate.hashCode());
result = prime * result
+ ((purchaseValue == null) ? 0 : purchaseValue.hashCode());
return result;
}
#Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
Assets other = (Assets) obj;
if (id == null) {
if (other.id != null)
return false;
} else if (!id.equals(other.id))
return false;
if (keyValueData == null) {
if (other.keyValueData != null)
return false;
} else if (!keyValueData.equals(other.keyValueData))
return false;
if (name == null) {
if (other.name != null)
return false;
} else if (!name.equals(other.name))
return false;
if (purchaseDate == null) {
if (other.purchaseDate != null)
return false;
} else if (!purchaseDate.equals(other.purchaseDate))
return false;
if (purchaseValue == null) {
if (other.purchaseValue != null)
return false;
} else if (!purchaseValue.equals(other.purchaseValue))
return false;
return true;
}
#Override
public String toString() {
return name;
}
}

You can set this keyValueData after deserialisation from your json string that contain the xml string as below
String jsoncontent=restTemplate.getForObject(constr+"getAssetdata/{Id}", String.class, curAcct.getiD());
final GsonBuilder gsonBuilder = new GsonBuilder();
gsonBuilder.registerTypeAdapter(Assets.class, new AssetDeserialiser());
final Gson gson = gsonBuilder.create();
Assets assetAcc = gson.fromJson(jsoncontent, Assets.class);
JSONObject jsonObj=new JSONObject(jsoncontent);
assetAcc.setKeyValueData(jsonObj.getString("keyValueData"));

1.Use Parcelable -its much faster.
2.Timestamp change to long. (Then can parce this value like this):
private String parceDate(data long){
SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd hh:mm");
try {
retrun df.format(your long from Assets.class);
}catch (Exception e){
return "";
}
}
UPDATE:
Y can change your getter and setter for use Timestamp object from Assets class like this:
public void setPurchaseDate(long purchaseDate){
this.purchaseDate=purchaseDate
}
public Timestamp getPurchaseDate(){
return new Timestamp(purchaseDate); //from java.sql.Timestamp;
}

You can use jackson for deserialization.
public class AssetDeserialiser extends JsonDeserializer<Asset> {
#Override
public Asset deserialize(JsonParser arg0, DeserializationContext arg1)
throws IOException, JsonProcessingException {
ObjectMapper mapper = new ObjectMapper();
JsonNode node = mapper.readTree(arg0);
final Asset asset = new Asset();
try{
asset.setId(mapper.readValue(node.get("id"),Integer.class));
asset.setName(mapper.readValue(node.get("name"),String.class));
asset.setPurchaseDate(mapper.readValue(node.get("purchaseDate"),Timestamp.class));
asset.setPurchaseValue(mapper.readValue(node.get("purchaseValue"),Float.class));
asset.setKeyValueData(mapper.readValue(node.get("keyValueData"), String.class));
}catch(Exception es){
System.out.println("es "+es);
}
return asset;
}
}
This may help you.
Also you will have to add "#JsonDeserialize(using=AssetDeserialiser.class)" at the beginning of your asset class. It is done like this:
#JsonDeserialize(using=AssetDeserialiser.class)
public class Asset implements Serializable{