I have a stream of objects coming from a server to a client. There is a networking class within the client which handles taking these objects. There is then an activity which uses a get method to get this object as it is updated from the server (both client classes are constantly updating) the objects also have a position field within them which determines if they are 1 (first), 2 (middle), or 3 (end) of the current stream of data.
My problem is that using LogCat to print these I get the first object with position 1, within the networking class, but the activity misses this, and displays several 2's and one 3. So it is somehow loosing my first object.
My client network has the following relevant code:
public class ClientNetwork implements Runnable {
Drawring serverDraw;
public Drawring GetServerDraw(){
Drawring drawPass = serverDraw;
return drawPass;
}
public void resetpos(){
serverDraw = null;
}
within public void run()
while(true){
while(true){
serverDraw =(com.DrawTastic.Drawring) ois.readObject();
test.add(serverDraw);
}
}
ClientActivity loops this:
try{
Drawring fromNet = net.GetServerDraw();
net.resetpos();
int position = fromNet.getPos();
switch (position) {
case 1:
try {
Log.d(null, "1st Position");
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
break;
case 2:
try {
Log.d(null, "2nd Position");
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
break;
case 3:
try {
Log.d(null, "3rd Position");
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
break;
}
}
catch(Exception e)
{
Log.d(null, e.toString());
}
Related
i am facing a problem regrading specifying the return data type. I have the FOComp class which implements callabale, the call() method of the 'FOComp' returns data type List<ArrayList<Mat>> as shown in the code of 'FOComp' class below.
and the method 'getResults()' returns data of type ArrayList<Mat> as shown in the code below. and currently, at run time, when I execute the code, I receive the folowing error:
Multiple markers at this line
The return type is incompatible with Callable<ArrayList<Mat>>.call()
The return type is incompatible with Callable<List<Mat>>.call()
kindly please let me know how to fix it.
'FOComp' class:
static class FOComp implements Callable<List<Mat>> {//should return list contains 4 mats(0,45,90,135)
private ArrayList<Mat> gaussianMatList = null;
private List<ArrayList<Mat>> results_4OrientAngles_List = null;
public FOComp(ArrayList<Mat> gaussianMatList) {
// TODO Auto-generated constructor stub
this.gaussianMatList = gaussianMatList;
this.results_4OrientAngles_List = new ArrayList<ArrayList<Mat>>();
}
public List<ArrayList<Mat>> call() throws Exception {
// TODO Auto-generated method stub
try {
featOrient = new FeatOrientation(this.gaussianMatList);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ExecutionException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
featOrient.start();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ExecutionException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
this.results_4OrientAngles_List.add(featOrient.getResults());
return results_4OrientAngles_List;
}
}
'getResults':
public ArrayList<Mat> getResults() {
if (this.crossAddOrientMapsList != null) {
if (!this.crossAddOrientMapsList.isEmpty()) {
if (this.crossAddOrientMapsList.size() == 4) {
double[] theta = new double[4];
theta[0] = 0;
theta[1] = 45;
theta[2] = 90;
theta[3] = 135;
for (int i = 0; i < this.crossAddOrientMapsList.size(); i++) {
MatFactory.writeMat(FilePathUtils.newOutputPath("FinalCrossAdd_" + theta[i]+"_degs"), this.crossAddOrientMapsList.get(i));
//ImageUtils.showMat(this.crossAddOrientMapsList.get(i), "OrientMap_" + theta[i] + " degs");
}
return this.crossAddOrientMapsList;
} else {
Log.WTF(TAG, "getResults", "crossAddOrientMapsList != 4 !!");
return null;
}
} else {
Log.E(TAG, "getResults", "crossAddOrientMapsList is empty.");
return null;
}
} else {
Log.E(TAG, "getResults", "crossAddOrientMapsList is null");
return null;
}
}
class FOComp implements Callable<List<Mat>>
and
public List<ArrayList<Mat>> call()
aren't really compatible... Your call() method should be
#Override public List<Mat> call()
Also, it is good practice to avoid implementation classes in method signatures, use the interfaces instead (in this case, use List rather than ArrayList). That will also fix your problem with one of the "multiple markers" :-)
Cheers,
You class declaration says that you are going to return a List of Mat (FOComp implements Callable<List<Mat>>), but your call method signature says you are going to return a List of ArrayList of Mat (List<ArrayList<Mat>>).
You will need to make them consistent.
Trying to learn about Jackson some, so I'm writing a simple program that reads a file/creates one to store some JSON in it. From the Jackson website I figured out how to read and write from the file, but in the case of my rudimentary program, i'd like to append as well. I'm basically trying to store a list of shopping lists. There is a shopping list object which has store name, amd items for that store.
The trouble is that I cannot figure a way to append another entry to the end of the file (in JSON format). Here is what I am working with so far, you can ignore the first bit it's just a silly console scanner asking for input:
public class JacksonExample {
static ObjectMapper mapper = new ObjectMapper();
static File file = new File("C:/Users/stephen.protzman/Desktop/user.json");
static List<ShoppingList> master = new ArrayList<ShoppingList>();
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
boolean running = true;
while (running) {
System.out.println("[ 1 ] Add a new shopping list");
System.out.println("[ 2 ] View all shopping lists");
System.out.println("[ 3 ] Save all shopping lists");
int choice = Integer.parseInt(in.nextLine());
switch (choice) {
case 1:
getNewList();
case 2:
display();
case 3:
running = false;
}
}
in.close();
}
public static void getNewList() {
boolean more = true;
String store, temp;
List<String> items = new ArrayList<String>();
Scanner s = new Scanner(System.in);
System.out.println("Enter the store: ");
store = s.nextLine();
System.out.println("Enter each item [If done type 'DONE'] :");
while (more) {
temp = s.nextLine();
if (temp != null) {
if (temp.toUpperCase().equals("DONE")) {
more = false;
} else {
items.add(temp);
}
}
}
save(store, items);
s.close();
}
public static void display() {
try {
ShoppingList list = mapper.readValue(file, ShoppingList.class);
System.out.println(mapper.defaultPrettyPrintingWriter()
.writeValueAsString(list));
} catch (JsonParseException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (JsonMappingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public static void save(String store, List<String> items) {
//load in old one
try {
ShoppingList list = mapper.readValue(file, ShoppingList.class);
System.out.println(mapper.defaultPrettyPrintingWriter()
.writeValueAsString(list));
} catch (JsonParseException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (JsonMappingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
//add to end of older list
ShoppingList tempList = new ShoppingList();
tempList.setStore(store);
tempList.setItems(items);
master.add(tempList);
try {
mapper.writeValue(file, master);
} catch (JsonGenerationException e) {
e.printStackTrace();
} catch (JsonMappingException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
I want to keep using ObjectMapper (considering im trying to learn Jackson) I just havent found a way to append yet is all. Any ideas?
To append content, you need to use Streaming API to create JsonGenerator; and then you can give this generator to ObjectMapper to write to. So something like:
JsonGenerator g = mapper.getFactory().createGenerator(outputStream);
mapper.writeValue(g, valueToWrite);
// and more
g.close();
Below method can be used to write objects into a json file in append mode. it first reads your existing json file and adds new java objects to JSON file.
public static void appendWriteToJson() {
ObjectMapper mapper = new ObjectMapper();
try {
// Object to JSON in file
JsonDaoImpl js = new JsonDaoImpl();
URL resourceUrl = js.getClass().getResource("/data/actionbean.json");
System.out.println(resourceUrl);
File file = new File(resourceUrl.toURI());
PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter(file, true))); // append mode file writer
mapper.writeValue(out, DummyBeanObject);
} catch (Exception e) {
e.printStackTrace();
}
}
I have an API that I use to retrieve daily schedules on the live cable-tv for various channels. I have a scenario in which I need a guidance as to which approach should work here.
Lets say I need schedules for 10 different channels from the API.
Should I execute 10 different async tasks for the retrieval of the required data?
Problem:
How would I collect the data in an arraylist and return it once all execution is completed?
How will I access the arraylist in my main function once onpostexecute returns the result?
Or I should just provide the list of channels to my single async task and make it build a single output of arraylist for my main function invoking it?
Problem:
Since I will be accessing a webservice for this purpose, will it make it run slow as compared to my 1st approach?
Second problem with this approach is the same as I am having with my 1st one, I need to know when and how to get the complete resultset once the execution of the task is completed?
Here is some code to explain the problem:
//going with the first approach
//invoking my asynctask from an activity or another class
//I need a global arraylist which I can use after postexecute returns its result
ArrayList<String> channels = channelManager.getAllChannelsByRegion("xyz");
final ArrayList<ChannelSchedule> schedules = new ArrayList<ChannelSchedule>();
final ObjectMapper mapper = new ObjectMapper(); // can reuse, share globally
for (int i = 0; i < channels.size(); ++i){
AsyncInvokeURLTask task = null;
try {
task = new AsyncInvokeURLTask(
channels.get(i), context, new AsyncInvokeURLTask.OnPostExecuteListener() {
#Override
public void onPostExecute(String result) {
// TODO Auto-generated method stub
try {
//Need to add results to arraylist here...But cannot know when it ends completely
ChannelSchedule schedule = mapper.readValue(result, ChannelSchedule.class);
Log.v("channel name", schedule.getChannelName());
Log.v("channel date", schedule.getDate());
Log.v("channel thumb", schedule.getListOfShows().get(0).getShowThumb());
Log.v("channel time", schedule.getListOfShows().get(0).getShowTime());
} catch (JsonParseException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (JsonMappingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
});
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
task.execute();
}
Please let me know if something is not clear or missing.
Launching 10 AsyncTask is perfectly fine.
You can keep a count of the number of pending requests. As OnPostExecute is run on the UI thread there are no risks of race condition.
private int numberOfPendingRequests;
public void MyFunc() {
ArrayList<String> channels = channelManager.getAllChannelsByRegion("xyz");
final ArrayList<ChannelSchedule> schedules = new ArrayList<ChannelSchedule>();
final ObjectMapper mapper = new ObjectMapper(); // can reuse, share globally
numberOfPendingRequests = channels.size();
for (int i = 0; i < channels.size(); ++i) {
schedules.add(null);
}
for (int i = 0; i < channels.size(); ++i) {
AsyncInvokeURLTask task = null;
final int index = i; // final so it can be used in the onPostExecute.
try {
task = new AsyncInvokeURLTask(
channels.get(i), context, new AsyncInvokeURLTask.OnPostExecuteListener() {
#Override public void onPostExecute(String result) {
try {
ChannelSchedule schedule = mapper.readValue(result, ChannelSchedule.class);
Log.v("channel name", schedule.getChannelName());
Log.v("channel date", schedule.getDate());
Log.v("channel thumb", schedule.getListOfShows().get(0).getShowThumb());
Log.v("channel time", schedule.getListOfShows().get(0).getShowTime());
schedules.set(index, schedule);
numberOfPendingRequests--;
if (numberOfPendingRequests == 0) {
// Everything is received, do stuff here.
}
} catch (JsonParseException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (JsonMappingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
});
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
task.execute();
}
}
I am trying to get the Message-Id of the sent message by using listeners.
I am implementing
javax.mail.event.TransportListener with concrete methods given in code sample.
It listens to javax.mail.event.TransportEvent which gets generated when void javax.mail.Transport.sendMessage(.....) is called.
To my surprise I get none of the method gets called when I actually send the mail..??? When does it actually get called ? Do I need to add any wait time after calling sendMessage(..)??
Doesn't it happen in real time ?
#Override
public void messageDelivered(TransportEvent e)
{
try {
System.out.println(e.getMessage().getHeader("Message-Id")[0]);
} catch (MessagingException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
}
#Override
public void messageNotDelivered(TransportEvent e)
{
try {
System.out.println(e.getMessage().getHeader("Message-Id")[0]);
} catch (MessagingException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
}
#Override
public void messagePartiallyDelivered(TransportEvent e)
{
try {
System.out.println(e.getMessage().getHeader("Message-Id")[0]);
} catch (MessagingException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
}
Did you register your listener with the Transport instance that's being used to send the message? Remember that the static Transport.send() method creates its own Transport instance that you never see.
I have a Java GUI application from which another java GUI application is invoked using reflection and loading. It works fine the only problem faced is, on closing the JFrame of invoked application the Main GUI application frame also closes. How can I prevent the main application (frame) from closing??
I cannot change the defaultCloseOperation of the invoked application, However a change to the main application can be made. Does it have any thing to do with threads??
This is my applications code that executes a target application
public class ClassExecutor{
private ClassLoaderOfExtClass classLoader;
private byte[][] ArrayOfClasses;
private String[] ArrayOfBinaryNames;
#SuppressWarnings("rawtypes")
private ArrayList<Class> loadedClasses;
private ArrayList<String> loadedClasesNames;
private Object[] parameters;
#SuppressWarnings("rawtypes")
public ClassExecutor() {
classLoader = new ClassLoaderOfExtClass();
new ArrayList<Class>();
loadedClasses = new ArrayList<Class>();
loadedClasesNames = new ArrayList<String>();
}
#SuppressWarnings("unchecked")
public void execute(File[] file, String[] binaryPaths) {
Object[] actuals = { new String[] { "" } };
Method m = null;
try {
Field classesx=ClassLoaderOfExtClass.class.getDeclaredField("classes");
classesx.setAccessible(true);
} catch (SecurityException e1) {
e1.printStackTrace();
} catch (NoSuchFieldException e1) {
e1.printStackTrace();
}
/*for (int i = 0; i < file.length; i++) {
for (int j = 0; j < file.length; j++) {
try {
#SuppressWarnings("rawtypes")
Class c = classLoader.loadClassCustom(file[i], binaryPaths[i]);
//Fied classex=classLoader.getResource("classes");
}catch(Exception e){
}
}
}
Class<?>[]classesxx= getLoadedClasses(classLoader);
System.out.println("Loaded classes have size "+ classesxx.length);*/
for (int i = 0; i < file.length; i++) {
try {
#SuppressWarnings("rawtypes")
Class c = classLoader.loadClassCustom(file[i], binaryPaths[i]);
try {
if (c.getMethod("main", new Class[] { String[].class }) != null) {
m = c.getMethod("main", new Class[] { String[].class });
} else {
System.out.println("This class does not contain main");
continue;
}
} catch (NoSuchMethodException e) {
// System.out.println("Main not found!!!");
// System.out.println("M here");
// e.printStackTrace(); // not printing stack trace
} catch (SecurityException e) {
e.printStackTrace();
}
} catch (ClassNotFoundException e) {
System.out.println("No such class definition exist!!");
// TODO Auto-generated catch block
// e.printStackTrace();
}
}
try {
m.invoke(null, actuals);
// CallStack.print();
} catch (IllegalArgumentException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InvocationTargetException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
#SuppressWarnings({ "unchecked", "rawtypes" })
public void execute(ArrayList<byte[]> stuffedFiles,
ArrayList<String> binaryPaths) {
convertToArray(stuffedFiles, binaryPaths);
loadAllClasses(ArrayOfClasses, ArrayOfBinaryNames);
Object[] actuals = { new String[] { "" } };
Method m = null;
/*
* Method[] m1= new Method[10]; for (Class c : loadedClasses) {
* m1=c.getMethods(); } for(Method m2: m1){
* System.out.println(m2.getName()); }
*/
/* System.out.println(loadedClasses.size()); */
for (Class c : loadedClasses) {
/*
* System.out.println(c.toString());
* System.out.println(c.getConstructors());
*/
// for (int i = 1; i < file.size(); i++) {
/*
* for(Method meth : c.getMethods()){ meth.setAccessible(true);
*
* }
*/
try {
if (c.getMethod("main", new Class[] { String[].class }) != null) {
m = c.getMethod("main", new Class[] { String[].class });
break;
} else {
// System.out.println("This class does not contain main");
continue;
}
} catch (NoSuchMethodException e) {
System.out.println("Program does not contain main");
} catch (SecurityException e) {
e.printStackTrace();
}
}
try {
if(parameters==null){
m.invoke(null, actuals);
}
else{
try {
System.out.println("It Fails Here");
m.invoke(null, parameters);
} catch (Exception e) {
System.out.println("Illegal arguments");
}
}
// CallStack.print();
} catch (IllegalArgumentException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InvocationTargetException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
You'll want to use the DISPOSE_ON_CLOSE operation, so it would be setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE)
EXIT_ON_CLOSE would be the option that closes all windows which I believe is what you are currently experiencing.
You have the following options for the defaultCloseOperation:
DO_NOTHING_ON_CLOSE - The do-nothing default window close operation;
HIDE_ON_CLOSE - The hide-window default window close operation;
DISPOSE_ON_CLOSE - The dispose-window default window close operation.
EXIT_ON_CLOSE - The exit application default window close operation. Attempting to set this on Windows that support this, such as JFrame, may throw a SecurityException based on the SecurityManager. It is recommended you only use this in an application.
The Option DISPOSE_ON_CLOSE could be used in order to avoid to close all windows, closing just the one you want.
If you don't have direct access to JFrame object as you have with the last posted code, you could use Window.getWindows() in order to receive all windows instance (as JFrame is a Window too it will be listed too). And then set the defaultCloseOperation on that.
Possibly you will need to use threads because the defaultCloseOperation needs to be set after invoke main method.
Theoretically it works, so I think this is a good shot ;)
I am not allowed to make changes to the application being invoked.
That was a comment in reply to #JeffLaJoie just to clarify, it would not require any changes to the code of the other app., just an extra method call or two by your app. at run-time to set the close operation of the 3rd party frame.
Failing that, the best solution I can think of is to start the new frame in a separate Process that starts a new JVM, when the user closes the other app., it and the 2nd JVM will end, while leaving the original app. on-screen.