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  • Java multiple connections downloading file

    - by weulerjunior
    Hello friends, I was wanting to add multiple connections in the code below to be able to download files faster. Could someone help me? Thanks in advance. public void run() { RandomAccessFile file = null; InputStream stream = null; try { // Open connection to URL. HttpURLConnection connection = (HttpURLConnection) url.openConnection(); // Specify what portion of file to download. connection.setRequestProperty("Range", "bytes=" + downloaded + "-"); // Connect to server. connection.connect(); // Make sure response code is in the 200 range. if (connection.getResponseCode() / 100 != 2) { error(); } // Check for valid content length. int contentLength = connection.getContentLength(); if (contentLength < 1) { error(); } /* Set the size for this download if it hasn't been already set. */ if (size == -1) { size = contentLength; stateChanged(); } // Open file and seek to the end of it. file = new RandomAccessFile("C:\\"+getFileName(url), "rw"); file.seek(downloaded); stream = connection.getInputStream(); while (status == DOWNLOADING) { /* Size buffer according to how much of the file is left to download. */ byte buffer[]; if (size - downloaded > MAX_BUFFER_SIZE) { buffer = new byte[MAX_BUFFER_SIZE]; } else { buffer = new byte[size - downloaded]; } // Read from server into buffer. int read = stream.read(buffer); if (read == -1) { break; } // Write buffer to file. file.write(buffer, 0, read); downloaded += read; stateChanged(); } /* Change status to complete if this point was reached because downloading has finished. */ if (status == DOWNLOADING) { status = COMPLETE; stateChanged(); } } catch (Exception e) { error(); } finally { // Close file. if (file != null) { try { file.close(); } catch (Exception e) { } } // Close connection to server. if (stream != null) { try { stream.close(); } catch (Exception e) { } } } }

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  • Will this Java regex return a single result or multiple

    - by Blankman
    If my HTML is: <tr><td>....</td><hr></tr> <tr><td>....</td><hr></tr> <tr><td>....</td><hr></tr> <tr><td>....</td><hr></tr> <tr><td>....</td><hr></tr> <tr><td>....</td><hr></tr> If my regex is: Patterp p = Pattern.compile("<tr>(.*)<hr></tr>"); Should this get 1 result or all the individual rows? Is there a way to force it to get all the rows and not just the entire html from the top <tr> to the last instance of <hr></tr> ?

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  • Java: Altering UI fonts (Nimbus) doesn't work!

    - by ivan_ivanovich_ivanoff
    Hello! I'm referring to this Nimbus reference. I tried to set global Font to be slightly larger: UIManager.put("defaultFont", new Font(Font.SANS_SERIF, 0, 16)); ...works only for the menu but nothing else (buttons, labels). I tried to change labels and buttons fonts with UIManager.put("Button.font", new Font(Font.SANS_SERIF, 0, 16)); UIManager.put("Label.font", new Font(Font.SANS_SERIF, 0, 16)); but the font remains. The only thing that worked for me was deriving a font: someButton.setFont(someButton.getFont().deriveFont(16f)); But this is not an option, since this must be done for each element manually. Note, that deriving a font for UIManager doesn't work either: UIManager.put("Label.font", UIManager.getFont("Label.font").deriveFont(16f)); I tested everything under Linux and Windows: same behavior. I just can't understand how an API can be so messy. If a method is called setFont(..) then I expect it to set the font. If this method fails to set the font in any thinkable circumstances, then it should be deprecated. EDIT: The problem not only applies to Nimbus, but also to the default LAF.

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  • Use Java Annotation not to run a method

    - by Michael Mao
    Hi all: I've got a method in my class only for testing purpose : private void printOut(String msg, Object value) { System.out.println(msg + value); } It is a wrapper method for System.out.println(); So I hope, with the use of Annotation, I can choose not to run this method during productive environment while still keep those diagnostic output ready if I am to switch back to debugging environment. Which Annotation shall I put on top of the method name?

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  • Returning searched results in an array in Java without ArrayList

    - by Crystal
    I started down this path of implementing a simple search in an array for a hw assignment without knowing we could use ArrayList. I realized it had some bugs in it and figured I'd still try to know what my bug is before using ArrayList. I basically have a class where I can add, remove, or search from an array. public class AcmeLoanManager { public void addLoan(Loan h) { int loanId = h.getLoanId(); loanArray[loanId - 1] = h; } public Loan[] getAllLoans() { return loanArray; } public Loan[] findLoans(Person p) { //Loan[] searchedLoanArray = new Loan[10]; // create new array to hold searched values searchedLoanArray = this.getAllLoans(); // fill new array with all values // Looks through only valid array values, and if Person p does not match using Person.equals() // sets that value to null. for (int i = 0; i < searchedLoanArray.length; i++) { if (searchedLoanArray[i] != null) { if (!(searchedLoanArray[i].getClient().equals(p))) { searchedLoanArray[i] = null; } } } return searchedLoanArray; } public void removeLoan(int loanId) { loanArray[loanId - 1] = null; } private Loan[] loanArray = new Loan[10]; private Loan[] searchedLoanArray = new Loan[10]; // separate array to hold values returned from search } When testing this, I thought it worked, but I think I am overwriting my member variable after I do a search. I initially thought that I could create a new Loan[] in the method and return that, but that didn't seem to work. Then I thought I could have two arrays. One that would not change, and the other just for the searched values. But I think I am not understanding something, like shallow vs deep copying???....

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  • Multiple threads modifying a collection in Java??

    - by posdef
    Hi, The project I am working on requires a whole bunch of queries towards a database. In principle there are two types of queries I am using: read from excel file, check for a couple of parameters and do a query for hits in the database. These hits are then registered as a series of custom classes. Any hit may (and most likely will) occur more than once so this part of the code checks and updates the occurrence in a custom list implementation that extends ArrayList. for each hit found, do a detail query and parse the output, so that the classes created in (I) get detailed info. I figured I would use multiple threads to optimize time-wise. However I can't really come up with a good way to solve the problem that occurs with the collection these items are stored in. To elaborate a little bit; throughout the execution objects are supposed to be modified by both (I) and (II). I deliberately didn't c/p any code, as it would be big chunks of code to make any sense.. I hope it make some sense with the description above. Thanks,

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  • Java 1.5.0_16 corrupted colours when saving jpg image

    - by Coder
    Hi, i have a loaded image from disk (stored as a BufferedImage), which i display correctly on a JPanel but when i try to re-save this image using the command below, the image is saved in a reddish hue. ImageIO.write(image, "jpg", fileName); Note! image is a BufferedImage and fileName is a File object pointing to the filename that will be saved which end in ".jpg". I have read that there were problems with ImageIO methods in earlier JDKs but i'm not on one of those versions as far as i could find. What i am looking for is a way to fix this issue without updating the JDK, however having said that i would still like to know in what JDK this issue was fixed in (if it indeed is still a bug with the JDK i'm using). Thanks.

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  • get particular string using regex java

    - by hussain
    i want to know how to get the string from group of string String j = "<a href=\"/watch?v=4Qx-lBqOqiQ&feature=popular\" onclick=\"\" onmousedown=\"yt.analytics.urchinTracker(\'/Events/Home/PersonalizedHome/POP/Logged_Out');\" ><span class=\"video-thumb video-thumb-220 \" id=\"video-thumb-4Qx-lBqOqiQ-8821469\"><img src=\"http://i1.ytimg.com/vi/4Qx-lBqOqiQ/hqdefault.jpg\" class=\"vimg220\" alt=\"Dog Squirrel Chasing A Squirrel\" title=\"Dog Squirrel Chasing A Squirrel\" onclick=\";yt.www.watch.watch5.IEshenanigans(event, this)\"><span class=\"video-time\"><span>1:08</span></span><span class=\"video-actions\"><button class=\"yt-uix-button-short yt-uix-button yt-uix-button-arrowbutton\" onclick=\"; return false;\" type=\"button\"> <img class=\"yt-uix-button-arrow\" src=\"http://s.ytimg.com/yt/img/pixel-vfl73.gif\" alt=\"\"> hai</a>"; i want to get the string href=\"/watch?v=4Qx-lBqOqiQ&feature=popular\" and src=\"http://i1.ytimg.com/vi/4Qx-lBqOqiQ/hqdefault.jpg\" thanks and advance

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  • serialize/deserialize a LinkedHashMap (android) java

    - by user348058
    So i want to pass a LinkedHashMap to an intent. //SEND THE MAP Intent singlechannel = new Intent(getBaseContext(),singlechannel.class); singlechannel.putExtra("db",shows1);//perase to startActivity(singlechannel); //GET THE MAP LinkedHashMap<String,String> db = new LinkedHashMap<String,String>(); db=(LinkedHashMap<String,String>) getIntent().getSerializableExtra("db"); This one Worked Like a charm with HashMap. But with LinkedHashMap i got a problem I got a warning "Type safety: Unchecked cast from Serializable to LinkedHashMap" But i had this warning with HashMap too? Any ideas.Any help is much appreciated Also I just saw this. https://issues.apache.org/jira/browse/HARMONY-6498

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  • How to re-use a thread in Java ?

    - by David
    I am a building a console Sudoku Solver where the main objective is raw speed. I now have a ManagerThread that starts WorkerThreads to compute the neibhbors of each cell. So one WorkerThread is started for each cell right now. How can I re-use an existing thread that has completed its work? The Thread Pool Pattern seems to be the solution, but I don't understand what to do to prevent the thread from dying once its job has been completed. ps : I do not expect to gain much performance for this particular task, just want to experiment how multi-threading works before applying it to the more complex parts of the code. Thanks

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  • org.apache.http.conn.HttpHostConnectException:Connection to http://172.20.38.143 refused

    - by Passion
    I have developed client server Application .I am accessing mysql with php running on my machine and client running on my cell which is connected to machine.WI-FI is also switched ON. Internet Permission are also added in Manifest file but then also the i encounter error 172.20.38.143 is IP OF MY MACHINE 06-01 13:20:10.391: W/System.err(11157): org.apache.http.conn.HttpHostConnectException: Connection to http://172.20.38.143 refused 06-01 13:20:10.401: W/System.err(11157): at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:183) 06-01 13:20:10.401: W/System.err(11157): at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164) 06-01 13:20:10.401: W/System.err(11157): at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119) 06-01 13:20:10.401: W/System.err(11157): at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360) 06-01 13:20:10.401: W/System.err(11157): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:674) 06-01 13:20:10.401: W/System.err(11157): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:511) 06-01 13:20:10.401: W/System.err(11157): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:489) 06-01 13:20:10.401: W/System.err(11157): at nineandroid.net.example.library.JSONParser.getJSONFromUrl(JSONParser.java:42) 06-01 13:20:10.401: W/System.err(11157): at nineandroid.net.example.library.UserFunctions.registerUser(UserFunctions.java:59) 06-01 13:20:10.401: W/System.err(11157): at nineandroid.net.example.RegisterActivity$1.onClick(RegisterActivity.java:52) 06-01 13:20:10.411: W/System.err(11157): at android.view.View.performClick(View.java:3567) 06-01 13:20:10.411: W/System.err(11157): at android.view.View$PerformClick.run(View.java:14224) 06-01 13:20:10.411: W/System.err(11157): at android.os.Handler.handleCallback(Handler.java:605) 06-01 13:20:10.411: W/System.err(11157): at android.os.Handler.dispatchMessage(Handler.java:92) 06-01 13:20:10.411: W/System.err(11157): at android.os.Looper.loop(Looper.java:137) 06-01 13:20:10.411: W/System.err(11157): at android.app.ActivityThread.main(ActivityThread.java:4517) 06-01 13:20:10.411: W/System.err(11157): at java.lang.reflect.Method.invokeNative(Native Method) 06-01 13:20:10.411: W/System.err(11157): at java.lang.reflect.Method.invoke(Method.java:511) 06-01 13:20:10.411: W/System.err(11157): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:993) 06-01 13:20:10.421: W/System.err(11157): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:760) 06-01 13:20:10.421: W/System.err(11157): at dalvik.system.NativeStart.main(Native Method) 06-01 13:20:10.421: W/System.err(11157): Caused by: java.net.ConnectException: failed to connect to /172.20.38.143 (port 80): connect failed: ENETUNREACH (Network is unreachable) 06-01 13:20:10.431: W/System.err(11157): at libcore.io.IoBridge.connect(IoBridge.java:114) 06-01 13:20:10.431: W/System.err(11157): at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:192) 06-01 13:20:10.431: W/System.err(11157): at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:459) 06-01 13:20:10.431: W/System.err(11157): at java.net.Socket.connect(Socket.java:848) 06-01 13:20:10.431: W/System.err(11157): at org.apache.http.conn.scheme.PlainSocketFactory.connectSocket(PlainSocketFactory.java:119) 06-01 13:20:10.431: W/System.err(11157): at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:144) 06-01 13:20:10.431: W/System.err(11157): ... 20 more 06-01 13:20:10.431: W/System.err(11157): Caused by: libcore.io.ErrnoException: connect failed: ENETUNREACH (Network is unreachable) 06-01 13:20:10.441: W/System.err(11157): at libcore.io.Posix.connect(Native Method) 06-01 13:20:10.441: W/System.err(11157): at libcore.io.BlockGuardOs.connect(BlockGuardOs.java:85) 06-01 13:20:10.441: W/System.err(11157): at libcore.io.IoBridge.connectErrno(IoBridge.java:127) 06-01 13:20:10.441: W/System.err(11157): at libcore.io.IoBridge.connect(IoBridge.java:112) 06-01 13:20:10.441: W/System.err(11157): ... 25 more 06-01 13:20:10.441: E/Buffer Error(11157): Error converting result java.lang.NullPointerException 06-01 13:20:10.451: E/JSON Parser(11157): Error parsing data org.json.JSONException: End of input at character 0 of 06-01 13:20:10.451: D/AndroidRuntime(11157): Shutting down VM 06-01 13:20:10.451: W/dalvikvm(11157): threadid=1: thread exiting with uncaught exception (group=0x40c0aa68) 06-01 13:20:10.451: E/AndroidRuntime(11157): FATAL EXCEPTION: main 06-01 13:20:10.451: E/AndroidRuntime(11157): java.lang.NullPointerException 06-01 13:20:10.451: E/AndroidRuntime(11157): at nineandroid.net.example.RegisterActivity$1.onClick(RegisterActivity.java:56) 06-01 13:20:10.451: E/AndroidRuntime(11157): at android.view.View.performClick(View.java:3567) 06-01 13:20:10.451: E/AndroidRuntime(11157): at android.view.View$PerformClick.run(View.java:14224) 06-01 13:20:10.451: E/AndroidRuntime(11157): at android.os.Handler.handleCallback(Handler.java:605) 06-01 13:20:10.451: E/AndroidRuntime(11157): at android.os.Handler.dispatchMessage(Handler.java:92) 06-01 13:20:10.451: E/AndroidRuntime(11157): at android.os.Looper.loop(Looper.java:137) 06-01 13:20:10.451: E/AndroidRuntime(11157): at android.app.ActivityThread.main(ActivityThread.java:4517) 06-01 13:20:10.451: E/AndroidRuntime(11157): at java.lang.reflect.Method.invokeNative(Native Method) 06-01 13:20:10.451: E/AndroidRuntime(11157): at java.lang.reflect.Method.invoke(Method.java:511) 06-01 13:20:10.451: E/AndroidRuntime(11157): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:993) 06-01 13:20:10.451: E/AndroidRuntime(11157): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:760) 06-01 13:20:10.451: E/AndroidRuntime(11157): at dalvik.system.NativeStart.main(Native Method) UserFunctions.java to call jsonParser public class UserFunctions { private JSONParser jsonParser; private static String loginURL = "http://172.20.38.143/ah_login_api/"; private static String registerURL = "http://172.20.38.143/ah_login_api/"; private static String login_tag = "login"; private static String register_tag = "register"; // constructor public UserFunctions(){ jsonParser = new JSONParser(); } /** * function make Login Request * @param email * @param password * */ public JSONObject loginUser(String email, String password){ // Building Parameters List<NameValuePair> params = new ArrayList<NameValuePair>(); params.add(new BasicNameValuePair("tag", login_tag)); params.add(new BasicNameValuePair("email", email)); params.add(new BasicNameValuePair("password", password)); JSONObject json = jsonParser.getJSONFromUrl(loginURL, params); // return json // Log.e("JSON", json.toString()); return json; } /** * function make Login Request * @param name * @param email * @param password * */ public JSONObject registerUser(String name, String email, String password){ // Building Parameters List<NameValuePair> params = new ArrayList<NameValuePair>(); params.add(new BasicNameValuePair("tag", register_tag)); params.add(new BasicNameValuePair("name", name)); params.add(new BasicNameValuePair("email", email)); params.add(new BasicNameValuePair("password", password)); // getting JSON Object JSONObject json = jsonParser.getJSONFromUrl(registerURL, params); // return json return json; } /** * Function get Login status * */ public boolean isUserLoggedIn(Context context){ DatabaseHandler db = new DatabaseHandler(context); int count = db.getRowCount(); if(count > 0){ // user logged in return true; } return false; } /** * Function to logout user * Reset Database * */ public boolean logoutUser(Context context){ DatabaseHandler db = new DatabaseHandler(context); db.resetTables(); return true; } } jsonParser.java public class JSONParser { static InputStream is = null; static JSONObject jObj = null; static String json = ""; // constructor public JSONParser() { } public JSONObject getJSONFromUrl(String url, List<NameValuePair> params) { // Making HTTP request try { // defaultHttpClient DefaultHttpClient httpClient = new DefaultHttpClient(); HttpPost httpPost = new HttpPost(url); httpPost.setEntity(new UrlEncodedFormEntity(params)); HttpResponse httpResponse = httpClient.execute(httpPost); HttpEntity httpEntity = httpResponse.getEntity(); is = httpEntity.getContent(); } catch (UnsupportedEncodingException e) { e.printStackTrace(); } catch (ClientProtocolException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } try { BufferedReader reader = new BufferedReader(new InputStreamReader( is, "iso-8859-1"), 8); StringBuilder sb = new StringBuilder(); String line = null; while ((line = reader.readLine()) != null) { sb.append(line + "\n"); } is.close(); json = sb.toString(); Log.e("JSON", json); } catch (Exception e) { Log.e("Buffer Error", "Error converting result " + e.toString()); } // try parse the string to a JSON object try { jObj = new JSONObject(json); } catch (JSONException e) { Log.e("JSON Parser", "Error parsing data " + e.toString()); } // return JSON String return jObj; } } RegisterActivity.java public class RegisterActivity extends Activity { Button btnRegister; Button btnLinkToLogin; EditText inputFullName; EditText inputEmail; EditText inputPassword; TextView registerErrorMsg; // JSON Response node names private static String KEY_SUCCESS = "success"; private static String KEY_UID = "uid"; private static String KEY_NAME = "name"; private static String KEY_EMAIL = "email"; private static String KEY_CREATED_AT = "created_at"; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.register); // Importing all assets like buttons, text fields inputFullName = (EditText) findViewById(R.id.registerName); inputEmail = (EditText) findViewById(R.id.registerEmail); inputPassword = (EditText) findViewById(R.id.registerPassword); btnRegister = (Button) findViewById(R.id.btnRegister); btnLinkToLogin = (Button) findViewById(R.id.btnLinkToLoginScreen); registerErrorMsg = (TextView) findViewById(R.id.register_error); // Register Button Click event btnRegister.setOnClickListener(new View.OnClickListener() { public void onClick(View view) { String name = inputFullName.getText().toString(); String email = inputEmail.getText().toString(); String password = inputPassword.getText().toString(); UserFunctions userFunction = new UserFunctions(); JSONObject json = userFunction.registerUser(name, email, password); // check for login response try { if (json.getString(KEY_SUCCESS) != null) { registerErrorMsg.setText(""); String res = json.getString(KEY_SUCCESS); if(Integer.parseInt(res) == 1){ // user successfully registred // Store user details in SQLite Database DatabaseHandler db = new DatabaseHandler(getApplicationContext()); JSONObject json_user = json.getJSONObject("user"); // Clear all previous data in database userFunction.logoutUser(getApplicationContext()); db.addUser(json_user.getString(KEY_NAME), json_user.getString(KEY_EMAIL), json.getString(KEY_UID), json_user.getString(KEY_CREATED_AT)); // Launch Dashboard Screen Intent dashboard = new Intent(getApplicationContext(), DashboardActivity.class); // Close all views before launching Dashboard dashboard.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP); startActivity(dashboard); // Close Registration Screen finish(); }else{ // Error in registration registerErrorMsg.setText("Error occured in registration"); } } } catch (JSONException e) { e.printStackTrace(); } } }); // Link to Login Screen btnLinkToLogin.setOnClickListener(new View.OnClickListener() { public void onClick(View view) { Intent i = new Intent(getApplicationContext(), LoginActivity.class); startActivity(i); // Close Registration View finish(); } }); } }

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  • Mouse event in Java

    - by Harish
    I am trying to move a JComponent say a label over a table.I am tracking this event using MouseMotionListener's mouseDragged method.This method perfectly helps me in tracking the item.Is there a way to track the mouse release after dragging is complete(.ie the dropping event). tktLabel1.addMouseMotionListener(new MouseMotionListener() { public void mouseDragged(MouseEvent arg0) { tktLabel1.setBounds(tktLabel1.getX() + arg0.getX(), tktLabel1.getY() + arg0.getY(), width, height); } public void mouseMoved(MouseEvent arg0) { } });

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  • Subqueries on Java GAE Datastore

    - by Dmitry
    I am trying to create a database of users with connection between users (friends list). There are 2 main tables: UserEntity (main field id) and FriendEntity with fields: - initiatorId - id of user who initiated the friendship - friendId - id of user who has been invited. Now I am trying to fetch all friends of one particular user and encountered some problems with using subqueries in JDO here. Logically the query should be something like this: SQL: SELECT * FROM UserEntity WHERE EXISTS (SELECT * FORM FriendEntity WHERE (initiatorId == UserEntity.id && friendId == userId) || (friendId == UserEntity.id && initiatorId == userId)) or SELECT * FROM UserEntity WHERE userId IN (SELECT * FROM FriendEntity WHERE initiatorId == UserEntity.id) OR userId IN (SELECT * FROM FriendEntity WHERE friendId == UserEntity.id) So to replicate the last query in JDOQL, I tried to do the following: Query friendQuery = pm.newQuery(FriendEntity.class); friendQuery.setFilter("initiatorId == uidParam"); friendQuery.setResult("friendId"); Query initiatorQuery = pm.newQuery(FriendEntity.class); initiatorQuery.setFilter("friendId == uidParam"); initiatorQuery.setResult("initiatorId"); Query query = pm.newQuery(UserEntity.class); query.setFilter("initiatorQuery.contains(id) || friendQuery.contains(id)"); query.addSubquery(initiatorQuery, "List initiatorQuery", null, "String uidParam"); query.addSubquery(friendQuery, "List friendQuery", null, "String uidParam"); query.declareParameters("String uidParam"); List<UserEntity> friends = (List<UserEntity>) query.execute(userId); In result I get the following error: Unsupported method while parsing expression. Could anyone help with this query please?

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  • java looping - declaration of a Class outside / inside the loop

    - by lisak
    when looping, for instance: for ( int j = 0; j < 1000; j++) {}; and I need to instantiate 1000 objects, how does it differ when I declare the object inside the loop from declaring it outside the loop ?? for ( int j = 0; j < 1000; j++) {Object obj; obj =} vs Object obj; for ( int j = 0; j < 1000; j++) {obj =} It's obvious that the object is accessible either only from the loop scope or from the scope that is surrounding it. But I don't understand the performance question, garbage collection etc. What is the best practice ? Thank you

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  • SwingWorker in Java (beginner question)

    - by Malachi
    I am relatively new to multi-threading and want to execute a background task using a Swingworker thread - the method that is called does not actually return anything but I would like to be notified when it has completed. The code I have so far doesn't appear to be working: private void crawl(ActionEvent evt) { try { SwingWorker<Void, Void> crawler = new SwingWorker<Void, Void>() { @Override protected Void doInBackground() throws Exception { Discoverer discover = new Discoverer(); discover.crawl(); return null; } @Override protected void done() { JOptionPane.showMessageDialog(jfThis, "Finished Crawling", "Success", JOptionPane.INFORMATION_MESSAGE); } }; crawler.execute(); } catch (Exception ex) { JOptionPane.showMessageDialog(this, ex.getMessage(), "Exception", JOptionPane.ERROR_MESSAGE); } } Any feedback/advice would be greatly appreciated as multi-threading is a big area of programming that I am weak in.

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  • Type conversion between PHP client and Java webservice

    - by a1ex07
    I have a web service implemented as EJB. One of it's methods returns Map<String,String>. On client side I use php : $client = new SoapClient($wsdl,array("cache_wsdl"=>WSDL_CACHE_NONE)); $result = $client->foo($params); Everything works fine, but I would like $result-return to be an associative array. Now it looks like array(10) { [0]=> object(stdClass)#46 (2) { ["key"]=> string(4) "key1" ["value"]=> string(4) "val1" } .... I want array(10) {"key1"=>"value1", "key2"=>"value2", .... } The obvious solution is to iterate through this array and create a new array $arr = array(); foreach ($result->return as $val) $arr[$val->key] = $val->value; But I wonder if there is a better way to get an assosicative array ? Thanks in advance.

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  • get eigenvalue pca with java

    - by Muhamad Burhanudin
    I try use PCA to reduce dimention, and i use jama for help me using matrix. but, i got problem when get eigenvalue with jama. for example i hava 2 image dimention 100x100, then i create single matrix 2 image x (100x100). there is 20.000 pixel. and how to get reduction with eigenvalue? this is sample my code : public static void main(String[] args) { BufferedImage bi; int[] rgb; int R, G, B; // int[] jum; double[][] gray = new double[500][500] ; String[] baris = new String[1000]; try { //bi = ImageIO.read(new File("D:\\c.jpg")); int[][] pixelData = new int[bi.getHeight() * bi.getWidth()][3]; int counter = 0; for (int i = 0; i < bi.getHeight(); i++) { for (int j = 0; j < bi.getWidth(); j++) { gray[i][j] = getPixelData(bi, i, j); // R = getR(bi, i, j); //G = getG(bi, i, j); //B = getB(bi, i, j); //jum = R + G + B; // gray[counter] = Double.toString(R + G + B / 3); // System.out.println("Gray " +gray); //for (int k = 0; k < rgb.length; k++) { // pixelData[counter][k] = rgb[k]; // } counter++; } } } catch (IOException e) { e.printStackTrace(); } Matrix matrix = new Matrix(gray); PCA pca = new PCA(matrix); pca.getEigenvalue(6); String n = pca.toString(); System.err.println("nilai n "+n); //double dete = pcadete(matrix,3600); } private static int getPixelData(BufferedImage bi, int x, int y) { int argb = bi.getRGB(y, x); int r, g, b; int gray; int rgb[] = new int[]{ (argb >> 16) & 0xff, //red (argb >> 8) & 0xff, //green (argb) & 0xff //blue }; r = rgb[0]; g = rgb[1]; b = rgb[2]; gray = (r + g + b) / 3; System.out.println("gray: " + gray); return gray; } when i show eigenvalue in this code : PCA pca = new PCA(matrix); pca.getEigenvalue(6); String n = pca.toString(); System.err.println("nilai n "+n); Result is : nilai n PCA@c3e9e9 Can, u tell me what way to get eigenvalue and reduction dimension.

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