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  • How to update only certain items in a list when using MVC?

    - by Eugen
    I'm building a GUI that includes a list with quite a lot of items. I allow the user to add/delete/edit those items. Up until now my update method called in the controller implied an entire JList reset (with its obvious performance issues). Now that there are hundreds of items available, updating the entire list is not fezable any longer. Does anyone know of a tutorial or can share an example (I haven't found any to suit my needs so far) in which the JList is updated something like JList.update(startIndex, endIndex);? Thanks for taking the time to answer.

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  • How did this get 8?

    - by David
    Here's the code: class qual { public static int fibonacci(int n) { if (n == 0 || n == 1) { return 1; } else { return fibonacci(n-1) + fibonacci(n-2); } } public static void main(String[] arg) { System.out.println(fibonacci(5)); } } The output was 8. The output should be 8 but when I look at this I think it should be 7 ((5-1) +(5-2)). Why was the output 8? I think the reasoning behind getting 8 will make recursion maybe stop being confusing for me.

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  • Address calling class

    - by Samuel
    I have an abstract class Moveable with the method abstract void move() which is extended by the class Bullet and the abstract class Character, and Character is extended by the class Survivor and the class Zombie. In Survivor and Bullet the move() method doesnt require any parameters while in the class Zombie the move() method depends on the actual position of the survivor. The survivor and multiple zombies are created in the class Gui. I wanted to access the survivor in Zombie - what's the best way of doing this? In Gui i wrote a method getSurvivor() but i don't see how to access this method in Zombie? I am aware that as a workaround i could just pass a [Survivor survivor] as parameter in move() and ignore it in Bullet and Survivor, but that feels so ... bad practice.

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  • Fast response on first Socket I/O request but slow every other time when communicating with remote serial port

    - by GreenGodot
    I'm using sockets to pass Serial commands to a remote device. And the response to that request is sent back and printed out. However, I am having a problem in that the first time it is instant but the rest of the time it can take up to 20 seconds to receive a reply. I think the problem is with my attempt at threading but I am not entirely sure. new Thread() { @Override public void run() { System.out.println("opened"); try { isSocketRetrieving.setText("Opening Socket"); socket = new Socket(getAddress(), getRemotePort())); DataOutput = new DataOutputStream(socket .getOutputStream()); inFromServer = new BufferedReader( new InputStreamReader(socket .getInputStream())); String line = ""; isSocketRetrieving.setText("Reading Stream......"); while ((line = inFromServer.readLine()) != null) { System.out.println(line); if (line.contains(getHandshakeRequest())) { DataOutput.write((getHandshakeResponse()toString() + "\r").getBytes()); DataOutput.flush(); DataOutput .write((getCommand().toString() + "\r").getBytes()); DataOutput.flush(); int pause = (line.length()*8*1000)/getBaud(); sleep(pause); } else if (line.contains(readingObject .getExpected())) { System.out.println(line); textArea.append("value = " + line + "\n"); textAreaScroll.revalidate(); System.out.println("Got Value"); break; } } System.out.println("Ended"); try { inFromServer.close(); DataOutput.close(); socket.close(); isSocketRetrieving.setText("Socket is inactive..."); rs232Table.addMouseListener(listener); interrupt(); join(); } catch (IOException e) { e.printStackTrace(); } catch (InterruptedException e) { System.out.println("Thread exited"); } } catch (NumberFormatException e1) { e1.printStackTrace(); } catch (UnknownHostException e1) { e1.printStackTrace(); } catch (IOException e1) { e1.printStackTrace(); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } } }.start();

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  • JPA Database strcture for internationalisation

    - by IrishDubGuy
    I am trying to get a JPA implementation of a simple approach to internationalisation. I want to have a table of translated strings that I can reference in multiple fields in multiple tables. So all text occurrences in all tables will be replaced by a reference to the translated strings table. In combination with a language id, this would give a unique row in the translated strings table for that particular field. For example, consider a schema that has entities Course and Module as follows :- Course int course_id, int name, int description Module int module_id, int name The course.name, course.description and module.name are all referencing the id field of the translated strings table :- TranslatedString int id, String lang, String content That all seems simple enough. I get one table for all strings that could be internationalised and that table is used across all the other tables. How might I do this in JPA, using eclipselink 2.4? I've looked at embedded ElementCollection, ala this... JPA 2.0: Mapping a Map - it isn't exactly what i'm after cos it looks like it is relating the translated strings table to the pk of the owning table. This means I can only have one translatable string field per entity (unless I add new join columns into the translatable strings table, which defeats the point, its the opposite of what I am trying to do). I'm also not clear on how this would work across entites, presumably the id of each entity would have to use a database wide sequence to ensure uniqueness of the translatable strings table. BTW, I tried the example as laid out in that link and it didn't work for me - as soon as the entity had a localizedString map added, persisting it caused the client side to bomb but no obvious error on the server side and nothing persisted in the DB :S I been around the houses on this about 9 hours so far, I've looked at this Internationalization with Hibernate which appears to be trying to do the same thing as the link above (without the table definitions it hard to see what he achieved). Any help would be gratefully achieved at this point... Edit 1 - re AMS anwser below, I'm not sure that really addresses the issue. In his example it leaves the storing of the description text to some other process. The idea of this type of approach is that the entity object takes the text and locale and this (somehow!) ends up in the translatable strings table. In the first link I gave, the guy is attempting to do this by using an embedded map, which I feel is the right approach. His way though has two issues - one it doesn't seem to work! and two if it did work, it is storing the FK in the embedded table instead of the other way round (I think, I can't get it to run so I can't see exactly how it persists). I suspect the correct approach ends up with a map reference in place of each text that needs translating (the map being locale-content), but I can't see how to do this in a way that allows for multiple maps in one entity (without having corresponding multiple columns in the translatable strings table)...

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  • Resultset (getter/setter class) object not deleting old values at 2nd Time execution in swin

    - by user2384525
    I have summarizeData() method and called so many time for value retrieve. but first time is working file but 2nd time execution value is increasing in HashMap. void summarizeData() { HashMap outerMap = new HashMap(); ArrayList list = new ArrayList(dataClass.getData()); for (int indx = 0; indx < list.size(); indx++) { System.out.println("indx : " + indx); Resultset rs = new Resultset(); rs = (Resultset) list.get(indx); if (rs != null) { int id = rs.getTestCaseNumber(); if (id > 0) { Object isExists = outerMap.get(id); if (isExists != null) { //System.out.println("found entry so updating"); Resultset inRs = new Resultset(); inRs = (Resultset) isExists; if (inRs != null) { int totExec = inRs.getTestExecution(); int totPass = inRs.getTestCasePass(); int totFail = inRs.getTestCaseFail(); // System.out.println("totE :" + totExec + " totP:" + totPass + " totF:" + totFail); int newRsStat = rs.getTestCasePass(); if (newRsStat == 1) { totPass++; inRs.setTestCasePass(totPass); } else { totFail++; inRs.setTestCaseFail(totFail); } totExec++; // System.out.println("id : "+id+" totPass: "+totPass+" totFail:"+totFail); // System.out.println("key : " + id + " val : " + inRs.getTestCaseNumber() + " " + inRs.getTestCasePass() + " " + inRs.getTestCaseFail()); inRs.setTestExecution(totExec); outerMap.put(id, inRs); } } else { // System.out.println("not exist so new entry" + " totE:" + rs.getTestExecution() + " totP:" + rs.getTestCasePass() + " totF:" + rs.getTestCaseFail()); outerMap.put(id, rs); } } } else { System.out.println("rs null"); } } Output at 1st Execution: indx : 0 indx : 1 indx : 2 indx : 3 indx : 4 indx : 5 indx : 6 indx : 7 indx : 8 indx : 9 indx : 10 totE :1 totP:1 totF:0 indx : 11 totE :1 totP:1 totF:0 indx : 12 totE :1 totP:1 totF:0 indx : 13 totE :1 totP:1 totF:0 indx : 14 totE :1 totP:1 totF:0 indx : 15 totE :1 totP:1 totF:0 indx : 16 totE :1 totP:1 totF:0 indx : 17 totE :1 totP:1 totF:0 indx : 18 totE :1 totP:1 totF:0 indx : 19 totE :1 totP:1 totF:0 Output at 2nd Execution: indx : 0 indx : 1 indx : 2 indx : 3 indx : 4 indx : 5 indx : 6 indx : 7 indx : 8 indx : 9 indx : 10 totE :2 totP:2 totF:0 indx : 11 totE :2 totP:2 totF:0 indx : 12 totE :2 totP:2 totF:0 indx : 13 totE :2 totP:2 totF:0 indx : 14 totE :2 totP:2 totF:0 indx : 15 totE :2 totP:2 totF:0 indx : 16 totE :2 totP:2 totF:0 indx : 17 totE :2 totP:2 totF:0 indx : 18 totE :2 totP:2 totF:0 indx : 19 totE :2 totP:2 totF:0 while i required same output on every execution.

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  • Need Help With Simple Regex

    - by npinti
    I have strings of this type: text (more text) What I would like to do is to have a regular expression that extracts the "more text" segment of the string, so far I have been using this regular expression: "^.*\\((.*)\\)$" Which although it works on many cases, it seems to fail if I have something of the sort: text (more text (even more text)) What I get is: even more text) What I would like to get instead is: more text (even more text) (basically the content of the outermost pair of brackets.) Thanks

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  • Trying to setup externalizing properties in spring

    - by Gandalf StormCrow
    Hi all, I'm building my project with maven so according to maven way, config should be in src/main/conf , how can I say to my spring application context that that is where jdbc.properties is found? Here is example bean : <bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer"> <property name="location" value="jdbc.properties" /> </bean> Spring assumens that this configuration is inside src/main/webapp/WEB-INF, I hope I've been clear if not I'll rephrase my question thank you

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  • hibernate insert to a collection causes a delete then all the items in the collection to be inserted

    - by Mark
    I have a many to may relationship CohortGroup and Employee. Any time I insert an Employee into the CohortGroup hibernate deletes the group from the resolution table and inserts all the members again, plus the new one. Why not just add the new one? The annotation in the Group: @ManyToMany(cascade = { PERSIST, MERGE, REFRESH }) @JoinTable(name="MYSITE_RES_COHORT_GROUP_STAFF", joinColumns={@JoinColumn(name="COHORT_GROUPID")}, inverseJoinColumns={@JoinColumn(name="USERID")}) public List<Employee> getMembers(){ return members; } The other side in the Employee @ManyToMany(mappedBy="members",cascade = { PERSIST, MERGE, REFRESH } ) public List<CohortGroup> getMemberGroups(){ return memberGroups; } Code snipit Employee emp = edao.findByID(cohortId); CohortGroup group = cgdao.findByID(Long.decode(groupId)); group.getMembers().add(emp); cgdao.persist(group); below is the sql reported in the log delete from swas.MYSITE_RES_COHORT_GROUP_STAFF where COHORT_GROUPID=? insert into swas.MYSITE_RES_COHORT_GROUP_STAFF (COHORT_GROUPID, USERID) values (?, ?) insert into swas.MYSITE_RES_COHORT_GROUP_STAFF (COHORT_GROUPID, USERID) values (?, ?) insert into swas.MYSITE_RES_COHORT_GROUP_STAFF (COHORT_GROUPID, USERID) values (?, ?) insert into swas.MYSITE_RES_COHORT_GROUP_STAFF (COHORT_GROUPID, USERID) values (?, ?) insert into swas.MYSITE_RES_COHORT_GROUP_STAFF (COHORT_GROUPID, USERID) values (?, ?) insert into swas.MYSITE_RES_COHORT_GROUP_STAFF (COHORT_GROUPID, USERID) values (?, ?) This seams really inefficient and is causing some issues. If sevral requests are made to add an employee to the group then some get over written.

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  • Sad logic on types

    - by user2972231
    Code base is littered with code like this: BaseRecord record = // some BaseRecord switch(record.source()) { case FOO: return process((FooRecord)record); case BAR: return process((BarRecord)record); case QUUX: return process((QuuxRecord)record); . . // ~25 more cases . } and then private SomeClass process(BarRecord record) { } private SomeClass process(FooRecord record) { } private SomeClass process(QuuxRecord record) { } It makes me terribly sad. Then, every time a new class is derived from BaseRecord, we have to chase all over our code base updating these case statements and adding new process methods. This kind of logic is repeated everywhere, I think too many to add a method for each and override in the classes. How can I improve this?

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  • Is Catching a Null Pointer Exception a Code Smell?

    - by Drew
    Recently a co-worker of mine wrote in some code to catch a null pointer exception around an entire method, and return a single result. I pointed out how there could've been any number of reasons for the null pointer, so we changed it to a defensive check for the one result. However, catching NullPointerException just seemed wrong to me. In my mind, Null pointer exceptions are the result of bad code and not to be an expected exception in the system. Are there any cases where it makes sense to catch a null pointer exception?

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  • Finding duplicates in a list using recursion?

    - by user1760892
    I'm suppose to find if there is duplicates in a list and return true or false using recursion only (no loops). So if ArrayList of char is used, [a,b,c,d,e] should return false. [a,a,b,c,d] or [a,b,b,c,c,d] should return true. I've tried and tested different ways and it worked for some cases but not all. I changed my code around and this is what I have now. (Has problem at the last if statement) Can anyone give me some hints? Thanks. public static <T> boolean duplicate(List<T> list) throws NullPointerException { return duplicateHelper(list, list.get(0)); } public static <T> boolean duplicateHelper(List<T> list, T t){ if (list == null) throw new NullPointerException(); if(list.isEmpty()) return false; if(list.size() > 1){ if(t.equals(list.get(1))) return true; } if(list.size() == 1) return false; if(!duplicateHelper(list.subList(1,list.size()), t)){ return duplicate(list.subList(1,list.size())); } return false; }

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  • How to re-order a List<String>

    - by tarka
    I have created the following method: public List<String> listAll() { List worldCountriesByLocal = new ArrayList(); for (Locale locale : Locale.getAvailableLocales()) { final String isoCountry = locale.getDisplayCountry(); if (isoCountry.length() > 0) { worldCountriesByLocal.add(isoCountry); Collections.sort(worldCountriesByLocal); } } return worldCountriesByLocal; } Its pretty simple and it returns a list of world countries in the users locale. I then sort it to get it alphabetic. This all works perfectly (except I seem to occasionally get duplicates of countries!). Anyway, what I need is to place the US, and UK at the top of the list regardless. The problem I have is that I can't isolate the index or the string that will be returned for the US and UK because that is specific to the locale! Any ideas would be really appreciated.

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  • Not compile code blocks when publishing?

    - by Menno Gouw
    I have many lines i just use for debugging and helpers. Is there a way i can mark these so they do not compile when publishing a project but still can use when running/debugging my program within Eclipse? Even better would be to mark a certain field as debug only and discard everything that has to do with that field completely when publishing. I understand this might get one in trouble when using fields like that and using that in critical parts of the code. But i often find myself initializing a lot of debug fields then comment them out which results in errors down the line if i do not comment those out as well. So is there some way to handle this in a better and more efficient way?

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  • Tile Engine: Entity location wrong

    - by Trizicus
    I've made a tile engine that has 30px by 30px. I've ran into a problem with an object for example. I've loaded an object 20px by 20px and when I do a collision check I have to use x/y position which is top left in Java2D. How can I do collision detection based on the entire object? This is relevant code: boolean checkCol() { int currentGridX = ship.getX()/30; int currentGridY = ship.getY()/30; if(test[currentGridX][currentGridY] == 0) return true; System.out.println("collision"); return false; }

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  • A beginner's JSF question about form validation

    - by Nitesh Panchal
    Hello, I am having a form and many input elements in that. I want certain fields to be validated, so i keep validateLenth etc on those. And i want some fields to not be validated. For example, i have contact information and address information both on the same page. I want to treat contact information as one group. So if some fields are invalid they should not be submitted and address information to be independent of contact information. Thus, if address information is corrected it should be submitted. I have one form only on the page but two buttons, one for address and one for contact. Simply put :- What is the equivalent of validationGroup of Asp.Net in JSF?

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  • How do I pass an array to a method?

    - by ambidextorous
    Hey, I have not been able to find a proper answer on any forums about this. But how exactly do I pass an array to a class constructor? public class TestArray { String name; String[] array; public TestArray(String name, String[] anArray){ this.name = name; int len = anArray.length; this.array = new String[len]; for (int i = 0; i < len; i++) { this.array[i] = new String(anArray[i]); } } public static void main(String[] args){ String[] anArray = new String[2]; anArray[0] = new String("Test"); anArray[1] = new String("Test2"); TestArray work = new TestArray("Jordan", anArray); // How to pass the array? } }

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  • Unable to decode hex values in javascript tooltip

    - by staudk27
    Hi all, I have quite the process that we go through in order to display some e-mail communications in our application. Trying to keep it as general as possible... -We make a request to a service via XML -Get the XML reply string, send the string to a method to encode any invalid characters as follows: public static String convertUTF8(String value) { char[] chars = value.toCharArray(); StringBuffer retVal = new StringBuffer(chars.length); for (int i = 0; i < chars.length; i++) { char c = chars[i]; int chVal = (int)c; if (chVal > Byte.MAX_VALUE) { retVal.append("&#x").append(Integer.toHexString(chVal)).append(";"); } else { retVal.append(c); } } return retVal.toString(); } We then send that result of a string to another method to remove any other invalid characters: public static String removeInvalidCharacters(String inString) { if (inString == null){ return null; } StringBuffer newString = new StringBuffer(); char ch; char c[] = inString.toCharArray(); for (int i = 0; i < c.length; i++) { ch = c[i]; // remove any characters outside the valid UTF-8 range as well as all control characters // except tabs and new lines if ((ch < 0x00FD && ch > 0x001F) || ch == '\t' || ch == '\n' || ch == '\r') { newString.append(ch); } } return newString.toString(); } This string is then "unmarshal'ed" via the SaxParser The object is then sent back to our Display action which generated the response to the calling jsp/javascript to create the page. The issue is some text can contain characters which can't be processed correctly. The following is eventually rendered on the JSP just fine: <PrvwCommTxt>This is a new test. Have a*&amp;#xc7;&amp;#xb4;)&amp;#xa1;.&amp;#xf1;&amp;#xc7;&amp;#xa1;.&amp;#xf1;*&amp;#xc7;&amp;#xb4;)...</PrvwCommTxt> Which shows up as "This is a new test. Have a*Ç´)¡.ñÇ¡." in the browser. -The following shows up in a tooltip while hovering over the above text: <CommDetails>This is a new test. Have a*Ç´)¡.ñÇ¡.ñ*Ç´)¡.ñ*´)(¡.ñÇ(¡.ñÇ* Wonderful Day!</CommDetails> This then shows up incorrectly when rendered in the tooltip javascript with all the HEX values and not being rendered correctly. Any suggestions on how to make the unknown characters show correctly in javascript?

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  • What technologies are appropriate for a human workflow system?

    - by CCw
    I'm researching various workflow architectures and it is overwhelming. The workflow system I am creating will be almost completely human-driven. Very little, if any, asynchronous activity will be taking place. One possibility is to simply use a RDBMS and have a task table, from which stored procedures would be used to enforce synchronous access to each task. This seems very simple, but I'm having a hard time coming up with reasons why I might need to involve a heavier solution. If my system has ~500 concurrent users, and there is very little in the way of automated or asynchronous tasks, should I even consider the various workflow patterns/packages out there like Mule, BPEL/SOA, Spring Work Flow, etc?

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  • Simple question about the lunarlander example.

    - by Smills
    I am basing my game off the lunarlander example. This is the run loop I am using (very similar to what is used in lunarlander). I am getting considerable performance issues associated with my drawing, even if I draw almost nothing. I noticed the below method. Why is the canvas being created and set to null each cycle? @Override public void run() { while (mRun) { Canvas c = null; try { c = mSurfaceHolder.lockCanvas();//null synchronized (mSurfaceHolder) { updatePhysics(); doDraw(c); } } finally { // do this in a finally so that if an exception is thrown // during the above, we don't leave the Surface in an // inconsistent state if (c != null) { mSurfaceHolder.unlockCanvasAndPost(c); } } } } Most of the times I have read anything about canvases it is more along the lines of: mField = new Bitmap(...dimensions...); Canvas c = new Canvas(mField); My question is: why is Google's example done that way (null canvas), what are the benefits of this, and is there a faster way to do it?

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  • regex: trim all strings directly preceeded by digit except if string belongs to predefined set of st

    - by Geert-Jan
    I've got addresses I need to clean up for matching purposes. Part of the process is trimming unwanted suffices from housenumbers, e.g: mainstreet 4a --> mainstreet 4. However I don't want: 618 5th Ave SW --> 618 5 Ave SW in other words there are some strings (for now: st, nd, rd, th) which I don't want to strip. What would be the best method of doing this (regex or otherwise) ? a wokring regex without the exceptions would be: a = a.replaceAll("(^| )([0-9]+)[a-z]+($| )","$1$2$3"); //replace 1a --> 1 I thought about first searching and substiting the special cases with special characters while keeping the references in a map, then do the above regex, and then doing the reverse substitute using the reference map, but I'm looking for a simpler solution. Thanks

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