convert recieved byte array to required instance of class in j2me - java-me

i m developing an application in j2me which features a Bluetooth Communication of an object of a user-defined class.
I received the byte array using following code:
public byte[] receiveBoard() {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
try {
ins = conn.openInputStream();
int n;
while((n=ins.read(brd))>0) {
baos.write(brd, 0, n);
}
} catch(Exception e) {
System.err.println(e);
}
return baos.toByteArray();
}
Correct me if this code is having mistakes.
Now my problem is,
i m not able to convert this "byte array" back to the requird instance of user-defined class. I m not able to retrieve my 'initial object' from the byte array, so that i can use it in my application again after the reception.
i tried using ObjectInputStream, ObjectInput classes but it is not importing those packages!!
Please Please help me fast!!!!

No it won't work, you have to make your own object serialization in J2ME. That means figuring out what properties of your object you want serialized, and writing your own code to write the object to a byte array, and read it back again.
You'll probably find DataInputStream and DataOutputStream very useful for this.

Related

Cucumber V5-V6 - passing complex object in feature file step

So I have recently migrated to v6 and I will try to simplify my question
I have the following class
#AllArgsConstructor
public class Songs {
String title;
List<String> genres;
}
In my scenario I want to have something like:
Then The results are as follows:
|title |genre |
|happy song |romance, happy|
And the implementation should be something like:
#Then("Then The results are as follows:")
public void theResultsAreAsFollows(Songs song) {
//Some code here
}
I have the default transformer
#DefaultParameterTransformer
#DefaultDataTableEntryTransformer(replaceWithEmptyString = "[blank]")
#DefaultDataTableCellTransformer
public Object transformer(Object fromValue, Type toValueType) {
ObjectMapper objectMapper = new ObjectMapper();
return objectMapper.convertValue(fromValue, objectMapper.constructType(toValueType));
}
My current issue is that I get the following error: Cannot construct instance of java.util.ArrayList (although at least one Creator exists)
How can I tell cucumber to interpret specific cells as lists? but keeping all in the same step not splitting apart? Or better how can I send an object in a steps containing different variable types such as List, HashSet, etc.
If I do a change and replace the list with a String everything is working as expected
#M.P.Korstanje thank you for your idea. If anyone is trying to find a solution for this here is the way I did it as per suggestions received. Inspected to see the type fromValue has and and updated the transform method into something like:
if (fromValue instanceof LinkedHashMap) {
Map<String, Object> map = (LinkedHashMap<String, Object>) fromValue;
Set<String> keys = map.keySet();
for (String key : keys) {
if (key.equals("genres")) {
List<String> genres = Arrays.asList(map.get(key).toString().split(",", -1));
map.put("genres", genres);
}
return objectMapper.convertValue(map, objectMapper.constructType(toValueType));
}
}
It is somehow quite specific but could not find a better solution :)

ADF RichSelectOneChoice get text (label)

I'm dealing with something that seems to be a trivial task but haven't found a solution: How can I access the text on a RichSelectOneChoice? I've only found the values with richSelectOneChoice.getValue() and valueChangeEvent.getNewValue()
But, how is it possible to access the actual text?
My last attempt was this:
private RichSelectOneChoice selClaim;
public void claimTypeVCL(ValueChangeEvent ve){
Map s = selClaim.getAttributes();
Object ss = s.get(ve.getNewValue());
System.out.println(ss);
}
At the moment the console output is null for the corresponding value, no matter what the choice is.
The ADF component bound to the RichSelectOneChoice object is created as a component with inner elements.
I've also tried the solution proposed by Frank Nimphius here https://community.oracle.com/thread/1050821 with the proper object type (RichSelectOneChoice) but the if clause doesn't execute because the children are not instanceof RichSelectOneChoice as suggested but rather javax.faces.component.UISelectItem and this class doesn't include the getLabel() method and running the code actually throws a wide range of errors related either to casting an object to the target type or null pointers when trying to access the label.
Solved it using the UISelectionItem object and its getItemValue() and getItemLabel() methods instead of getLabel() or getValue(), the latter of which was available but didn't render the expected result.
The working code looks like this:
public String selectedOptionStr;
public void socClaimTypeVCL(ValueChangeEvent ve){
selectedOptionStr = "";
RichSelectOneChoice sct = (RichSelectOneChoice)ve.getSource();
List childList = sct.getChildren();
for (int i = 0; i < childList.size(); i++) {
if (childList.get(i) instanceof javax.faces.component.UISelectItem) {
javax.faces.component.UISelectItem csi = (javax.faces.component.UISelectItem) childList.get(i);
if (csi.getItemValue().toString() == ve.getNewValue().toString()) {
selectedOptionStr = csi.getItemLabel();
}
}
}
}

ordering of Hashtable in J2ME

I have some data and I have added them to Hashtable in some orders what I want to do now is to get the data in the same order that I have entered
What is the data type that I can use?
Assuming your key is a String you could add some ordering to it and have a getter method for the sorted data. See example below:
static int order;
Hashtable map = new Hashtable();
void put (String key, Object value) {
map.put(order + key, value);
order++;
}
Enumeration getSorted() {
Enumeration keys = map.keys();
Vector sortedKeys = new Vector();
while (keys.hasMoreElements()) {
String key = (String) keys.nextElement();
insertionSort(key, sortedKeys);
}
Vector sortedData = new Vector();
keys = sortedKeys.elements();
while (keys.hasMoreElements()) {
String key = (String) keys.nextElement();
sortedData.addElement(map.get(key));
}
return sortedData.elements();
}
You can find insertionSort algorithms at http://en.wikipedia.org/wiki/Insertion_sort
A Hashtable does not retain any ordering.
If you need insertion order access see if Linked Hash Map is offered in JavaME
You can download a source code of Java SE and make work LinkedHashMap in J2ME easily by removing generics (but also you might need to perform this on it's parent classes and interfaces).
You can find LinkedHashMap for Java ME here

Serializing Objects in AS3, String type too small to hold blob

I'm using:
import flash.utils.ByteArray;
import mx.utils.Base64Encoder;
import mx.utils.Base64Decoder;
.
.
.
public static function serializeToString(value:Object):String{
if(value==null){
throw new Error("null isn't a legal serialization candidate");
}
var bytes:ByteArray = new ByteArray();
bytes.writeObject(value);
bytes.position = 0;
var be:Base64Encoder = new Base64Encoder();
be.encode(bytes.readUTFBytes(bytes.length));
return be.drain();
}
public static function deSerializeFromString(value:String):Object{
var dec:Base64Decoder=new Base64Decoder();
dec.decode(value);
var result:ByteArray=dec.drain();
result.position=0;
return result.readObject();
}
But I keep getting an "Error #2030: End of file was encountered."
This is (probably) because the class I'm serializing is too big for the "String" object type in AS3.
Is there a limitless object for storing an array of characters (or better yet binary), or am I going to have to make my own class? (like one with an array of strings)
Another efficient, cross-platform way of serializing objects is by using JSON.
Here is a library for as3:
https://github.com/mherkender/actionjson

Adding different object types to a c# 4.0 collection

I have a function that returns objects of different types based on the parameter passed to this function.
Is it possible to add these different object types to a collection based on some identifier in C# 4.0?
Usually we do something like this
List or List
but i want one collection which can add object of any type.
Instead of just making a List<object> like other posters are recommending, you may want to define an interface eg IListableObject that contains a few methods that your objects need to implement. This will make any code using these objects much easier to write and will guard against unwanted objects getting into the collection down the line.
Yes, it is called object. Eg:
var objlist = new List<object>();
objlist.Add(1);
objlist.Add(true);
objlist.Add("hello");
You could use object[], List<object>, ArrayList, IEnumerable, ... but if those types have a common base type it would be better to stick to a strongly typed collection.
Really your collection should be as specific as you can make it. When you say
objects of different types
Do these objects have anything in common? Do they implement a common interface?
If so you you can specialise the list on that interface List<IMyInterface>
Otherwise List<object> will do what you want.
Update
No, not really.
I'm sorry but I'm going to question your design.
If you have a collection of different objects, how do you decide how to use one of the objects?
You're going to have a large switch statement switching on the type of the object, then you cast to a specific object and use it.
You also have have a similar switch statement in your factory method that creates the object.
One of the benefits of Object Orientation is that if you design your objects correctly then you don't need to do these large "If it's this object do this.Method(), if it's that object do that.OtherMethod()".
Can I ask, why are you putting different objects into the same collection? What's the benefit to you?
If you want a collection which can add objects of any type then List<object> is the most appropriate type.
Collections in earlier versions of C# (not generics) can contain any kind of objects. If they're value type, they will be boxed into object.
When you need to use them, you can just cast it to the original type.
You may use List<Type> to hold the type information, if that's what you want. And Type[], Hashtable, etc. are also fine. You can use typeof operator to get the type or use Object.GetType().
Also check out Dynamic type.
http://msdn.microsoft.com/en-us/library/dd264736.aspx
It will basically do the same thing.
My Suggestion:
public class ParamValue
{
object value = null;
public ParamValue(object val)
{
value = val;
}
public string AsString()
{
return value.ToString();
}
public int AsInt()
{
return int.Parse(value.ToString());
}
public int? AsNullableInt()
{
int n;
if (int.TryParse(value.ToString(), out n))
{
return n;
}
return null;
}
public bool AsBool()
{
return bool.Parse(value.ToString());
}
public bool? AsNullableBool()
{
bool b;
if (bool.TryParse(value.ToString(), out b))
{
return b;
}
return null;
}
}
public class Params
{
Dictionary<string, object> paramCol = new Dictionary<string, object>();
public void Add(string paramName, object value)
{
paramCol.Add(paramName, value);
}
public ParamValue this[string paramName]
{
get
{
object v;
if (paramCol.TryGetValue(paramName, out v))
{
return new ParamValue(v);
}
return null;
}
}
}
Use param class as a collectio to your values, you can convert the return to every type you want.
You could use a Tuple of Genric Types
public Tuple<T, T> MySuperMethod()
{
int number = 1;
string text = "Batman";
return new Tuple<int, string>(number, text);
}
The .NET Framework directly supports tuples with one to seven
elements. In addition, you can create tuples of eight or more elements
by nesting tuple objects in the Rest property of a Tuple object.
https://msdn.microsoft.com/en-us/library/system.tuple(v=vs.100).aspx

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