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  • Does the JPQL avg aggregate function work with Integers?

    - by Kyle Renfro
    I have a JPA 2 Entity named Surgery. It has a member named transfusionUnits that is an Integer. There are two entries in the database. Executing this JPQL statement: Select s.transfusionUnits from Surgery s produces the expected result: 2 3 The following statement produces the expected answer of 5: Select sum(s.transfusionUnits) from Surgery s I expect the answer of the following statement to be 2.5, but it returns 2.0 instead. Select avg(s.transfusionUnits) from Surgery s If I execute the statement on a different (Float) member, the result is correct. Any ideas on why this is happening? Do I need to do some sort of cast in JPQL? Is this even possible? Surely I am missing something trivial here.

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  • Is there anything wrong with my Factory class?

    - by Alex
    class PieceFactory { @SuppressWarnings("rawtypes") public Piece createPiece(String pieceType) throws Throwable{ Class pieceClass = Class.forName(pieceType); Piece piece = (Piece) pieceClass.newInstance(); return piece; } } I'm not all used to handling exceptions yet therefore I'm just throwing them, but everywhere I use a method that uses this factory it tells me I have to throw exceptions like throwable. For example, in one of my classes I have a method that instantiates a lot of objects using the method that uses the factory. I can use the method in that class by just throwing the exception, however it won't work if I try to pass a reference to that class to another class and then use the method from there. Then it forces me to try catch the exception. I probably don't need a factory but it seemed interesting and I'd like to try to use patterns. The reason I created the factory was that I have 6 subclasses of Piece and I wan't to use a method to instantiate them by passing the type of subclass I want as an argument to the method.

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  • Convert InputStream to String with encoding given in stream data

    - by Quentin
    Hi, My input is a InputStream which contains an XML document. Encoding used in XML is unknown and it is defined in the first line of XML document. From this InputStream, I want to have all document in a String. To do this, I use a BufferedInputStream to mark the beginning of the file and start reading first line. I read this first line to get encoding and then I use an InputStreamReader to generate a String with the correct encoding. It seems that it is not the best way to achieve this goal because it produces an OutOfMemory error. Any idea, how to do it ? public static String streamToString(final InputStream is) { String result = null; if (is != null) { BufferedInputStream bis = new BufferedInputStream(is); bis.mark(Integer.MAX_VALUE); final StringBuilder stringBuilder = new StringBuilder(); try { // stream reader that handle encoding final InputStreamReader readerForEncoding = new InputStreamReader(bis, "UTF-8"); final BufferedReader bufferedReaderForEncoding = new BufferedReader(readerForEncoding); String encoding = extractEncodingFromStream(bufferedReaderForEncoding); if (encoding == null) { encoding = DEFAULT_ENCODING; } // stream reader that handle encoding bis.reset(); final InputStreamReader readerForContent = new InputStreamReader(bis, encoding); final BufferedReader bufferedReaderForContent = new BufferedReader(readerForContent); String line = bufferedReaderForContent.readLine(); while (line != null) { stringBuilder.append(line); line = bufferedReaderForContent.readLine(); } bufferedReaderForContent.close(); bufferedReaderForEncoding.close(); } catch (IOException e) { // reset string builder stringBuilder.delete(0, stringBuilder.length()); } result = stringBuilder.toString(); }else { result = null; } return result; } Regards, Quentin

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  • JPA joined column allow every value...

    - by Fabio Beoni
    I'm testing JPA, in a simple case File/FileVersions tables (Master/Details), with OneToMany relation, I have this problem: in FileVersions table, the field "file_id" (responsable for the relation with File table) accepts every values, not only values from File table. How can I use the JPA mapping to limit the input in FileVersion.file_id only for values existing in File.id? My class are File and FileVersion: FILE CLASS @Id @GeneratedValue(strategy = GenerationType.IDENTITY) @Column(name="FILE_ID") private Long id; @Column(name="NAME", nullable = false, length = 30) private String name; //RELATIONS ------------------------------------------- @OneToMany(mappedBy="file", fetch=FetchType.EAGER) private Collection <FileVersion> fileVersionsList; //----------------------------------------------------- FILEVERSION CLASS @Id @GeneratedValue(strategy = GenerationType.IDENTITY) @Column(name="VERSION_ID") private Long id; @Column(name="FILENAME", nullable = false, length = 255) private String fileName; @Column(name="NOTES", nullable = false, length = 200) private String notes; //RELATIONS ------------------------------------------- @ManyToOne(fetch=FetchType.EAGER) @JoinColumn(name="FILE_ID", referencedColumnName="FILE_ID", nullable=false) private File file; //----------------------------------------------------- and this is the FILEVERSION TABLE CREATE TABLE `JPA-Support`.`FILEVERSION` ( `VERSION_ID` bigint(20) NOT NULL AUTO_INCREMENT, `FILENAME` varchar(255) NOT NULL, `NOTES` varchar(200) NOT NULL, `FILE_ID` bigint(20) NOT NULL, PRIMARY KEY (`VERSION_ID`), KEY `FK_FILEVERSION_FILE_ID` (`FILE_ID`) ) ENGINE=MyISAM AUTO_INCREMENT=4 DEFAULT CHARSET=latin1

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  • 500 Worker Threads, what kind of thread pool?

    - by Submerged
    I am wondering if this is the best way to do this. I have about 500 threads that run indefinitely, but Thread.sleep for a minute when done one cycle of processing. ExecutorService es = Executors.newFixedThreadPool(list.size()+1); for (int i = 0; i < list.size(); i++) { es.execute(coreAppVector.elementAt(i)); //coreAppVector is a vector of extends thread objects } The code that is executing is really simple and basically just this class aThread extends Thread { public void run(){ while(true){ Thread.sleep(ONE_MINUTE); //Lots of computation every minute } } } I do need a separate threads for each running task, so changing the architecture isn't an option. I tried making my threadPool size equal to Runtime.getRuntime().availableProcessors() which attempted to run all 500 threads, but only let 8 (4xhyperthreading) of them execute. The other threads wouldn't surrender and let other threads have their turn. I tried putting in a wait() and notify(), but still no luck. If anyone has a simple example or some tips, I would be grateful! Well, the design is arguably flawed. The threads implement Genetic-Programming or GP, a type of learning algorithm. Each thread analyzes advanced trends makes predictions. If the thread ever completes, the learning is lost. That said, I was hoping that sleep() would allow me to share some of the resources while one thread isn't "learning"

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  • Draw a position from a 2d Array on respected canvas location

    - by Anon
    Background: I have two 2d arrays. Each index within each 2d array represents a tile which is drawn on a square canvas suitable for 8 x 8 tiles. The first 2d array represents the ground tiles and is looped and drawn on the canvas using the following code: //Draw the map from the land 2d array map = new Canvas(mainFrame, 20, 260, 281, 281); for(int i=0; i < world.length; i++){ for(int j=0; j < world[i].length; j++){ for(int x=0; x < 280; x=x+35){ for(int y=0; y < 280; y=y+35){ Point p = new Point(x,y); map.add(new RectangleObject(p,35,35,Colour.green)); } } } } This creates a grid of green tiles 8 x 8 across as intended. The second 2d array represents the position on the ground. This 2d array has everyone of its indexes as null apart from one which is comprised of a Person class. Problem I am unsure of how I can draw the position on the grid. I was thinking of a similar loop, so it draws over the previous 2d array another set of 64 tiles. Only this time they are all transparent but the one tile which isn't null. In other words, the tile where Person is located. I wanted to use a search throughout the loop using a comparative if statement along the lines of if(!(world[] == null)){ map.add(new RectangleObject(p,35,35,Colour.red));} However my knowledge is limited and I am confused on how to implement it.

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  • Eclipse Class File Metadata

    - by Alex
    In Visual Studio, I can obtain a succinct list of public methods/members exposed in a class for which I do not have the source (i.e. bundled inside a DLL) by pressing F12 (GoToDefinition). Similarly, I am learning the Android API - in Eclipse. Jumping to an Android framework method definition produces decompilation output which is not intuitive to read, and is very verbose. To mimic results like Visual Studio, I am considering several options: How can I format the decompilation output to be 'cleaner' - I have looked through Eclipse's preferences menus and have not found a way to do this. How do I 'add corresponding source files' once Google provides it, so that jumping to definition yields the actual definition? Is there a plugin that does this already? I looked into Jadclipse, but that project has not been updated in several years, and is still a decompiler. Thank you in advance.

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  • How to embed XBase expressions in an Xtext DSL

    - by Marcus Mathioudakis
    I am writing a simple little DSL for specifying constraints on messages, and Have been trying without success for a while to embed XBase expressions into the language. The Grammar looks like this: grammar org.xtext.businessrules.BusinessRules with org.eclipse.xtext.xbase.Xbase //import "http://www.eclipse.org/xtext/xbase/Xbase" as xbase import "http://www.eclipse.org/xtext/common/JavaVMTypes" as jvmTypes generate businessRules "http://www.xtext.org/businessrules/BusinessRules" Start: rules+=Constraint*; Constraint: {Constraint} 'FOR' 'PAYLOAD' payload=PAYLOAD 'ELEMENT' element=ID 'CONSTRAINED BY' constraint=XExpression; PAYLOAD: "SimulationSessionEvents" |"stacons" |"any" ; Range: 'above' min=INT ('below' max=INT)? |'below' max=INT ('above' min=INT)? ; When trying to parse a file such as: FOR PAYLOAD SimulationSessionEvents ELEMENT matrix CONSTRAINED BY ... I can't get it to work for ... = any kind of Arithmetic expression, although it works for ...= loop or if expression, or even just a number. As soon as I do something like '-5' or '4-5' it says Couldn't resolve reference to JvmIdentifiableElement '-', even though the Xbase.xtext Grammar looks like it allows these expressions. I don't think I'm missing any Jars, as it doesn't complain when I run the mwe workflow, but only when trying to parse the input file. Any help would be much appreciated.

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  • Accessing FacesContext from Web Service

    - by scriptmonster
    I'm developing a Web Service which will be called by clients which are written by me. In the web service I need to use application-wide objects which eases the load of application on the system. I have implemented my application-wide objects as shown in this question. I can use my object in a jsf page with no problem as follows. MyObject mo = (MyObject) FacesContext.getCurrentInstance().getExternalContext().getApplicationMap().get("MyObjectsName"); But when it comes to use it in a Web Service Request FacesContext.getCurrentInstance() returns null. Is there any way to use the FacesContext in a web service.

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  • mockito ArrayList<String> problem...

    - by Sardathrion
    I have a method that I am trying to unit test. This method takes a parameter as an ArrayList and does things with it. The mock I am trying to define is: ArrayList<String> mocked = mock(ArrayList.class); which gives a [unchecked] unchecked conversion" warning. ArrayList<String> mocked = mock(ArrayList<String>.class); gives me an error. Anyone care to enlighten me as to what I am doing wrong?

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  • Comparing text files w/ Junit

    - by jon077
    I am comparing text files in junit using: public static void assertReaders(BufferedReader expected, BufferedReader actual) throws IOException { String line; while ((line = expected.readLine()) != null) { assertEquals(line, actual.readLine()); } assertNull("Actual had more lines then the expected.", actual.readLine()); assertNull("Expected had more lines then the actual.", expected.readLine()); } Is this a good way to compare text files? What is preferred?

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  • ArrayList<String> NullPointerException

    - by Carlucho
    Am trying to solve a labyrinth by DFS, using adj List to represent the vertices and edges of the graph. In total there are 12 nodes (3 rows[A,B,C] * 4 cols[0,..,3]). My program starts by saving all the vertex labels (A0,..C3), so far so good, then checks the adjacent nodes, also no problems, if movement is possible, it proceeds to create the edge, here its where al goes wrong. adjList[i].add(vList[j].label); I used the debugger and found that vList[j].label is not null it contains a correct string (ie. "B1"). The only variables which show null are in adjList[i], which leads me to believe i have implemented it wrongly. this is how i did it. public class GraphList { private ArrayList<String>[] adjList; ... public GraphList(int vertexcount) { adjList = (ArrayList<String>[]) new ArrayList[vertexCount]; ... } ... public void addEdge(int i, int j) { adjList[i].add(vList[j].label); //NULLPOINTEREXCEPTION HERE } ... } I will really appreaciate if anyone can point me on the right track regrading to what its going wrong... Thanks!

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  • Strange profiling results: definitely non-bottleneck method pops up

    - by jkff
    I'm profiling a program using sampling profiling in YourKit and JProfiler, and also "manually" (I launch it and press Ctrl-Break several times to get thread dumps). All three methods give me extremely strange results: some tens of percents of time spent in a 3-line method that does not even do any allocation or synchronization and doesn't have loops etc. Moreover, after I made this method into a NOP and even removed its invocation completely, the observable program performance didn't change at all (although it got a negligible memory leak, since it was a method for freeing a cheap resource). I'm thinking that this might be because of the constraints that JVM puts on the moments at which a thread's stacktrace may be taken, and it somehow turns out that in my program it is exactly the moments where this method is invoked, although there is absolutely nothing special about it or the context in which it is invoked. What can be the explanation for this phenomenon? What are the aforementioned constraints? What further measurements can I take to clarify the situation?

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  • What is a right way to use servlets?

    - by vikp
    Hi, I'm studying EJB3. I have a session bean which provides services to create/update customer accounts. This session bean offers services on the lines of: public void addCustomer(Customer c); public void updateCustomer(Customer c); Ideally I'd like to have a single servlet: CustomerServlet and it would invoke the session beans that I have listed above. Problem is that I have two JSPs: UpdateAccount.jsp and CreateAccount.jsp. Both of these JSPs have a form with a method POST and action "CustomerServlet". How can I distinguish in a customer servlet which operation I should carry out: createAccount or updateAccount? I guess the alternative is to have a separate servlet for each operation... Thank you

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  • Spring Dispatcher Servlet Not Found Problem

    - by hamam
    I'm trying to build a simple spring web application but I get the following error when I run it on Apache Tomcat 6.0 Class Not Found Exception org.springframework.web.servlet.DispatcherServlet I'm using maven to handle libraries. At first I thought it was maven's fault but it adds spring and other libraries succesfully. I tried to import "org.springframework.web.servlet.DispatcherServlet" in a source file and my project has the right package and classes. My development environment : Ubuntu 10.4 Eclipse IDE Tomcat 6.0 I'd appreciate any help

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  • Apache HttpClient 4.0. Weird behavior.

    - by Mikhail T
    Hello. I'm using Apache HttpClient 4.0 for my web crawler. The behavior i found strange is: i'm trying to get page via HTTP GET method and getting response about 404 HTTP error. But if i try to get that page using browser it's done successfully. Details: 1. I upload multipart form to server this way: HttpPost httpPost = new HttpPost("http://[host here]/in.php"); MultipartEntity entity = new MultipartEntity(HttpMultipartMode.BROWSER_COMPATIBLE); entity.addPart("method", new StringBody("post")); entity.addPart("key", new StringBody("223fwe0923fjf23")); FileBody fileBody = new FileBody(new File("photo.jpg"), "image/jpeg"); entity.addPart("file", fileBody); httpPost.setEntity(entity); HttpResponse response = httpClient.execute(httpPost); HttpEntity result = response.getEntity(); String responseString = ""; if (result != null) { InputStream inputStream = result.getContent(); byte[] buffer = new byte[1024]; while(inputStream.read(buffer) > 0) responseString += new String(buffer); result.consumeContent(); } Uppload succefully ends. I'm getting some results from web server: HttpGet httpGet = new HttpGet("http://[host here]/res.php?key="+myKey+"&action=get&id="+id); HttpResponse response = httpClient.execute(httpGet); HttpEntity entity = response.getEntity(); I'm getting ClientProtocolException while execute method run. I was debugging this situation with log4j. Server answers "404 Not Found". But my browser loads me that page with no problem. Can anybody help me? Thank you.

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  • Invoke Maven-Module build from intellij

    - by Roman
    Hi All I was wondering if someone knows a way to invoke a specific maven module build from IntelliJ that will also build ( or use already compiled classes ) from depended modules. So for instance if I would like to build the module "Model" in the picture and only it , it seems reasonable for me to click the package step on it. But what is actually does it invokes the mvn package step inside this specific module rather than "mvn -am -pl module-name" from the root module , which also builds all the dependencies. So is there something that I just don't know ?

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  • MouseMotion Sensor Method Call

    - by user321894
    I have a soon-to-be due assignment due in computer science. I have encountered a problem, for which no matter how long I study the API's of the class and superclasses, I can not figure out. Suppose I wish to design a sort of "Breakout game" where the mouse motion controls the motion of a block that is used to bounce a ball, which then destroys multi colored bricks. How do you specifically make the block "listen" to the mouse? The below code is what I have attempted to achieve the desired results. /** Breakout Program*/ public class Breakout extends GraphicsProgram implements MouseMotionListener { ... /** The Paddle Itself */ private GRect paddle = new GRect(0, HEIGHT-PADDLEBOTTOM_OFFSET, PADDLEWIDTH, PADDLEHEIGHT); ... /** Run the Breakout program. */ public void run() { paddle.setFillColor(Color.BLACK); paddle.setFilled(true); add(paddle); paddle.addMouseListener(this); ... } /** Move the horizontal middle of the paddle to the x-coordinate of the mouse position - * -but keep the paddle completely on the board. */ public void mouseMoved(MouseEvent e) { GPoint p= new GPoint(e.getPoint()); double x = p.getX(); paddle.setLocation(x, HEIGHT-PADDLEBOTTOM_OFFSET); } } Any clarification on why/what I am doing incorrectly would be helpful, thanks.

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  • Efficient representation of Hierarchies in Hibernate.

    - by Alison G
    I'm having some trouble representing an object hierarchy in Hibernate. I've searched around, and haven't managed to find any examples doing this or similar - you have my apologies if this is a common question. I have two types which I'd like to persist using Hibernate: Groups and Items. * Groups are identified uniquely by a combination of their name and their parent. * The groups are arranged in a number of trees, such that every Group has zero or one parent Group. * Each Item can be a member of zero or more Groups. Ideally, I'd like a bi-directional relationship allowing me to get: * all Groups that an Item is a member of * all Items that are a member of a particular Group or its descendants. I also need to be able to traverse the Group tree from the top in order to display it on the UI. The basic object structure would ideally look like this: class Group { ... /** @return all items in this group and its descendants */ Set<Item> getAllItems() { ... } /** @return all direct children of this group */ Set<Group> getChildren() { ... } ... } class Item { ... /** @return all groups that this Item is a direct member of */ Set<Group> getGroups() { ... } ... } Originally, I had just made a simple bi-directional many-to-many relationship between Items and Groups, such that fetching all items in a group hierarchy required recursion down the tree, and fetching groups for an Item was a simple getter, i.e.: class Group { ... private Set<Item> items; private Set<Group> children; ... /** @return all items in this group and its descendants */ Set<Item> getAllItems() { Set<Item> allItems = new HashSet<Item>(); allItems.addAll(this.items); for(Group child : this.getChildren()) { allItems.addAll(child.getAllItems()); } return allItems; } /** @return all direct children of this group */ Set<Group> getChildren() { return this.children; } ... } class Item { ... private Set<Group> groups; /** @return all groups that this Item is a direct member of */ Set<Group> getGroups() { return this.groups; } ... } However, this resulted in multiple database requests to fetch the Items in a Group with many descendants, or for retrieving the entire Group tree to display in the UI. This seems very inefficient, especially with deeper, larger group trees. Is there a better or standard way of representing this relationship in Hibernate? Am I doing anything obviously wrong or stupid? My only other thought so far was this: Replace the group's id, parent and name fields with a unique "path" String which specifies the whole ancestry of a group, e.g.: /rootGroup /rootGroup/aChild /rootGroup/aChild/aGrandChild The join table between Groups and Items would then contain group_path and item_id. This immediately solves the two issues I was suffering previously: 1. The entire group hierarchy can be fetched from the database in a single query and reconstructed in-memory. 2. To retrieve all Items in a group or its descendants, we can select from group_item where group_path='N' or group_path like 'N/%' However, this seems to defeat the point of using Hibernate. All thoughts welcome!

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