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  • JPA - Performance with using multiple entity manager

    - by Nguyen Tuan Linh
    My situation is: The code is not mine I have two kinds of database: one is Dad, one is Son. In Dad, I have a table to store JNDI name. I will look up Dad using JNDI, create entity manager, and retrieve this table. From these retrieved JNDI names, I will create multiple entity managers using multiple Son databases. The problem is: Son have thousands of entities. It takes each Son database around 10 minutes to load all entities. If there is 4 Son databases, it will be 40 minutes. My question: Is there any way to load all entities and use them for all entity manager? Please look at the code below For each Son JNDI: Map<String, String> puSonProperties = new HashMap<String, String>(); puSonProperties.put("javax.persistence.jtaDataSource", sonJndi); EntityManagerFactory emf = Persistence.createEntityManagerFactory("PUSon", puSonProperties); PUSon - All of them use the same persistence unit log.info("Verify entity manager for son: {0} - {1}", sonCode, emSon.find(Son_configuration.class, 0) != null ? "ok" : "failed!"); This is the actual code where the loading of all entities begins. 10 mins.

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  • Android Hashtable Serialization

    - by Nsyed
    Hi All, I am having a weird issue with serialization of a Hashtable. I have made a Server, Client app. Where server(PC/MAC) is serializing a Hashtable and sending it to Client(Android) through UDP. The data is sent/read correctly but I get a bunch of these messages below on LogCat. 04-12 11:19:43.059: DEBUG/dalvikvm(407): GetFieldID: unable to find field Ljava/util/Hashtable;.loadFactor:F Occasionally, I would see these 04-12 11:21:19.150: DEBUG/dalvikvm(407): GC freed 10814 objects / 447184 bytes in 97ms The app would run for 2-3 mins and then crash. Interestingly enough I do not see the Loadfactor errors on SDK 1.5. But I do see the GC Free xxxx objects, quiet often. After debugging I have found that the issue is with de-serialization and the error/warning are coming from following code Code: ByteArrayInputStream bis = new ByteArrayInputStream(bytes); ObjectInputStream ois = new ObjectInputStream(bis); object = ois.readObject(); at Code: object = ois.readObject(); on the client. My server is serializing code is the following. Code: ByteArrayOutputStream bos = new ByteArrayOutputStream(); ObjectOutputStream oos = new ObjectOutputStream(bos); oos.writeObject(obj); Any idea what is going on? Thanks for the Help!

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  • Swingworker producing duplicate output/output out of order?

    - by Stefan Kendall
    What is the proper way to guarantee delivery when using a SwingWorker? I'm trying to route data from an InputStream to a JTextArea, and I'm running my SwingWorker with the execute method. I think I'm following the example here, but I'm getting out of order results, duplicates, and general nonsense. Here is my non-working SwingWorker: class InputStreamOutputWorker extends SwingWorker<List<String>,String> { private InputStream is; private JTextArea output; public InputStreamOutputWorker(InputStream is, JTextArea output) { this.is = is; this.output = output; } @Override protected List<String> doInBackground() throws Exception { byte[] data = new byte[4 * 1024]; int len = 0; while ((len = is.read(data)) > 0) { String line = new String(data).trim(); publish(line); } return null; } @Override protected void process( List<String> chunks ) { for( String s : chunks ) { output.append(s + "\n"); } } }

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  • null != null - any ideas on how to re-arrange the code or prevent this?

    - by Alex
    Currently debugging, and found an if-statement which for no (I thought...) reason gave me an NPE, obviously for a reason. Which seemed to be that the statement turned out to be if(false && (null != null || null != Color)). if(destination != null && (destination.getPiece() != null || destination.getPiece().getColour() != pieceColour)) - the if-statement Both destination can be null and piece can be. The getColour() method returns an attribute of type Color from piece, which must be null if the piece is null. The piece at destination has a different pieceColour attribute then the one in the if-statement. Specifically, how do I re-arrange (destination.getPiece() != null) ?

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  • How to define GPS module in Android?

    - by Osama Gamal
    I'm porting android to Devkit8000 which is a BeagleBoard clone. I have a GPS module connected on /dev/ttyS0. I could successfully get NMEA output when writing "cat /dev/ttyS0" in the terminal emulator. I want to know how to let android know that there is a GPS module on /dev/ttyS0 and it is outputting NMEA standard? To be able to use the android.location class with it! Is there something to edit in the android's source? adding driver for example, writing a code with android-ndk or what?

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  • method names with fluent interface

    - by deamon
    I have a Permissions class with methods in fluent style like this: somePermissions.setRead(true).setWrite(false).setExecute(true) The question is, whether I should name these methods set{Property} or only {property}. The latter would look like this: somePermissions.read(true).write(false).execute(true) If I look at these methods separately I would expect that read reads something, but on the other hand it is closer to the intention to have something like named paramaters like in Scala: Permission(read=true, write=false, execute=true)

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  • Maven String Replace of Text Web Resources

    - by Jaco van Niekerk
    I have a Maven web application with text files in src/main/webapp/textfilesdir As I understand it, during the package phase this textfilesdir directory will be copied into the target/project-1.0-SNAPSHOT directory, which is then zipped up into a target/project-1.0-SNAPSHOT.war Problem Now, I need to do a string replacement on the contents of the text files in target/project-1.0-SNAPSHOT/textfilesdir. This must then be done after the textfilesdir is copied into target/project-1.0-SNAPSHOT, but prior to the target/project-1.0-SNAPSHOT.war file being created. I believe this is all done during the package phase. How can a plugin (potentially maven-antrun-plugin), plug into the package phase to do this. The text files don't contain properties, like ${property-name} to filter on. String replacement is likely the only option. Options Modify the text files after the copy into target/project-1.0-SNAPSHOT directory, yet prior to the WAR creation. After packaging, extract the text files from WAR, modify them, and add them back into the WAR. I'm thinking there is another option here I'm missing. Thoughts anyone?

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  • Using java2d user space measurements with TextLayout and LineBreakMeasurer

    - by Andrew Wheeler
    I have a java2d image defined in user space (mm) to print an identity card. The transformation to pixels is by using an AffineTransform for the required DPI (Screen or print). I want to wrap text across several lines but the the TextLayout does not respect user space co-ordinates. private void drawParagraph(Graphics2D g2d, Rectangle2D area, String text) { LineBreakMeasurer lineMeasurer; AttributedString string = new AttributedString(text); AttributedCharacterIterator paragraph = string.getIterator(); int paragraphStart = paragraph.getBeginIndex(); int paragraphEnd = paragraph.getEndIndex(); FontRenderContext frc = g2d.getFontRenderContext(); lineMeasurer = new LineBreakMeasurer(paragraph, frc); float breakWidth = (float)area.getWidth(); float drawPosY = (float)area.getY(); float drawPosX = (float)area.getX(); lineMeasurer.setPosition(paragraphStart); while (lineMeasurer.getPosition() < paragraphEnd) { TextLayout layout = lineMeasurer.nextLayout(breakWidth); drawPosY += layout.getAscent(); layout.draw(g2d, drawPosX, drawPosY); drawPosY += layout.getDescent() + layout.getLeading(); } } The above code determines font metrics using user space sizing of the Font and thus turn out rather large. The font size is calculated as best vertical fit for the number of lines in an area with the calculation as below. E.g. attr.put(TextAttribute.SIZE, (geTextArea().getHeight() / noOfLines - LINE_SPACING) ); When using g2d.drawString("Some text to display", x, y); the font size appears correct. Does anyone have a better way of doing text layout in user space co-ords?

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  • StringTokenizer split at "<br/>"

    - by AnAmuser
    Maybe I am stupid but I don't understand why the behaviour of StringTokenizer here: import static org.apache.commons.lang.StringEscapeUtils.escapeHtml; String object = (String) value; String escaped = escapeHtml(object); StringTokenizer tokenizer = new StringTokenizer(escaped, escapeHtml("<br/>")); If fx. value is Hej<br/>$user.get(0).name Har vundet<br/><table border='1'><tr><th>Name</th><th>Played</th><th>Brewed</th></tr>#foreach( $u in $user )<tr><td>$u.name</td> <td>$u.played</td> <td>$u.brewed</td></tr>#end</table><br/> Then the result is Hej $use . e (0).name Ha vunde a e o de ='1' h Name h h P ayed h h B ewed h #fo each( $u in $use ) d $u.name d d $u.p ayed d d $u. ewed d #end a e It makes no sense to me. How can I make it behave as I expect to.

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  • addNotify not works allright

    - by joseph
    Hello. I call addNotify() method in class that I posted here. The problem is, that when I call addNotify() as it is in the code, setKeys(objs) do nothing. Nothing appears in my explorer of running app. But when I call addNotify()without loop(for int....), and add only one item to ArrayList, it shows that one item correctly. Does anybody knows where can be problem? See the cede class ProjectsNode extends Children.Keys{ private ArrayList objs = new ArrayList(); public ProjectsNode() { } @Override protected Node[] createNodes(Object o) { MainProject obj = (MainProject) o; AbstractNode result = new AbstractNode (new DiagramsNode(), Lookups.singleton(obj)); result.setDisplayName (obj.getName()); return new Node[] { result }; } @Override protected void addNotify() { //this loop causes nothing appears in my explorer. //but when I replace this loop by single line "objs.add(new MainProject("project1000"));", it shows that one item in explorer for (int i=0;i==10;i++){ objs.add(new MainProject("project1000")); } setKeys (objs); } }

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  • Distributed sequence number generation?

    - by Jon
    I've generally implemented sequence number generation using database sequences in the past. e.g. Using Postgres SERIAL type http://neilconway.org/docs/sequences/ I'm curious though as how to generate sequence numbers for large distributed systems where there is no database. Does anybody have any experience or suggestions of a best practice for achieving sequence number generation in a thread safe manner for multiple clients?

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  • Saving twice don't update my object in JDO

    - by Javi
    Hello I have an object persisted in the GAE datastore using JDO. The object looks like this: public class MyObject implements Serializable, StoreCallback { @PrimaryKey @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY) @Extension(vendorName="datanucleus", key="gae.encoded-pk", value="true") private String id; @Persistent private String firstId; ... } As usually when the object is stored for the first time a new id value is generated for the identifier. I need that if I don't provide a value for firstId it sets the same value as the id. I don't want to solve it with a special getter which checks for null value in firstId and then return the id value because I want to make queries relating on firstId. I can do it in this way by saving the object twice (Probably there's a better way to do this, but I'll do it in this way until I find a better one). But it is not working. when I debug it I can see that result.firstId is set with the id value and it seems to be persisted, but when I go into the datastore I see that firstId is null (as it was saved the first time). This save method is in my DAO and it is called in another save method in the service annotated with @Transactional. Does anyone have any idea why the second object in not persisted properly? @Override public MyObject save(MyObject obj) { PersistenceManager pm = JDOHelper.getPersistenceManagerFactory("transactions-optional"); MyObject result = pm.makePersistent(obj); if(result.getFirstId() == null){ result.setFirstId(result.getId()); result = pm.makePersistent(result); } return result; } Thanks.

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  • Why does ActiveMQ hold messages that should be deleted from Topic?

    - by rauch
    I use ActiveMQ as Notification System(Pub/Sub model). On server: if any changes of data occur, Server send this updated data (File) to Topic using BlobMessages. There are few Clients, that subscribe on this Topic and get updated File if it exsist in Topic. The problem is that all of BlobMessages, that were sent to Topic, are hold by ActiveMQ all time. this.producer = new ProducerTool.Builder("tcp://localhost:61616?jms.blobTransferPolicy.uploadUrl=http://localhost:8161/fileserver/", "ServerProdTopic").topic(true) .transacted(false).durable(false).timeToLive(10000L).build(); this.consumer = new ConsumerTool.Builder("tcp://localhost:61616", "ServerConsTopic").topic(true) .transacted(false).durable(false).build(); consumer.setMessageListener(this); The File is sent: connection = createConnection(); session = createSession(connection); producer = createProducer(session); BlobMessage blobMsg = ((ActiveMQSession) session).createBlobMessage(resource); blobMsg.setStringProperty("sourceName", resource.getName()); producer.send(blobMsg); if (transacted) { System.out.println("Producer Committing..."); session.commit(); } Where createProducer is: protected Connection createConnection() throws JMSException, Exception { ActiveMQConnectionFactory connectionFactory = new ActiveMQConnectionFactory(url); //connectionFactory.getBlobTransferPolicy().setUploadUrl("http://localhost:8161/fileserver/"); Connection connection = connectionFactory.createConnection(); connection.start(); ((ActiveMQConnection) connection).setCopyMessageOnSend(false); return connection; } All, that could be useful I set as need: Session.AUTO_ACKNOWLEDGE; Non-Durable Subscription; TimeToLive = 9000; JMSDeliveryMode = Non-Persistent; What I have at runtime: in ActiveMQ directory: ~/apache-activemq-5.3.0/webapps/fileserver/ tere are all File, that where delivered and not delivered to Subscribers. Why? Sometimes Server send Big Files about 1 GB....And even this Files are hold at that directory, Even after stopping Subscribers(Clients), Publisher(Server) and ActiveMQ Broker.

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  • how can i unmarshall in jaxb and enjoy the schema validation without using an explicit schema file

    - by ekeren
    I am using jaxb for my application configurations I feel like I am doing something really crooked and I am looking for a way to not need an actual file or this transaction. As you can see in code I: 1.create a schema into a file from my JaxbContext (from my class annotation actually) 2.set this schema file in order to allow true validation when I unmarshal JAXBContext context = JAXBContext.newInstance(clazz); Schema mySchema = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI).newSchema(schemaFile); jaxbContext.generateSchema(new MySchemaOutputResolver()); // ultimately creates schemaFile Unmarshaller u = m_context.createUnmarshaller(); u.setSchema(mySchema); u.unmarshal(...); do any of you know how I can validate jaxb without needing to create a schema file that sits in my computer? Do I need to create a schema for validation, it looks redundant when I get it by JaxbContect.generateSchema ? How do you do this?

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  • How to remove the file suffix/extension (.jsp and .action) using the Stripes Framework?

    - by Dolph Mathews
    I'm looking to use pretty / clean URL's in my web app. I would like the following URL: http://mydomain.com/myapp/calculator .. to resolve to: com.mydomain.myapp.action.CalculatorActionBean I tried overwriting the NameBasedActionResolver with: public class CustomActionResolver extends NameBasedActionResolver { public static final String DEFAULT_BINDING_SUFFIX = "."; @Override protected String getBindingSuffix() { return DEFAULT_BINDING_SUFFIX; } @Override protected List<String> getActionBeanSuffixes() { List<String> suffixes = new ArrayList<String>(super.getActionBeanSuffixes()); suffixes.add(DEFAULT_BINDING_SUFFIX); return suffixes; } } And adding this to web.xml: <servlet-mapping> <servlet-name>StripesDispatcher</servlet-name> <url-pattern>*.</url-pattern> </servlet-mapping> Which gets me to: http://mydomain.com/myapp/Calculator. But: A stray "." is still neither pretty nor clean. The class name is still capitalized in the URL..? That still leaves me with *.jsp..? Is it even possible to get rid of both .action and .jsp?

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  • Capturing Set Behavior with Mutating Elements

    - by Carl
    Using the Guava library, I have the following situation: SetMultimap<ImmutableFoo, Set<Foo>> setMM = HashMultimap.create(); Set<Foo> mask = Sets.newHashSet(); // ... some iteration construct { setMM.put(ImmutableFoo1, Sets.difference(SomeSetFoo1,mask)); setMM.put(ImmutableFoo1, Sets.difference(SomeSetFoo2,mask)); mask.add(someFoo); } that is, the same iteration to create the setMM is also used to create the mask - this can of course result in changes to hashCode()s and create duplicates within the SetMultimap backing. Ideally, I'd like the duplicates to drop without me having to make it happen, and avoid repeating the iteration to separately construct the multimap and mask. Any easy libraries/Set implementations to make that happen? Alternatively, can you identify a better way to drop the duplicates than: for (ImmutableFoo f : setMM.keySet()) setMM.putAll(f,setMM.removeAll(f)); revisiting the elements is probably not a performance problem, since I could combine a separate filter operation that needs to visit all the elements anyway.

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  • Order of parts in SMTP multipart messages

    - by Chris
    Hi, I'd like to know how to build an SMTP multipart message in the correct order so that it will render correctly on the iPhone mail client (rendering correctly in GMail). I'm using Javamail to build up an email containing the following parts: A body part with content type "text/html; UTF-8" An embedded image attachment. A file attachment I am sending the mail via GMail SMTP (via SSL) and the mail is sent and rendered correctly using a GMail account, however, the mail does not render correctly on the iPhone mail client. On the iPhone mail client, the image is rendered before the "Before Image" text when it should be rendered afterwards. After the "Before Image" text there is an icon with a question mark (I assume it means it couldn't find the referenced CID). I'm not sure if this is a limitation of the iPhone mail client or a bug in my mail sending code (I strongly assume the latter). I think that perhaps the headers on my parts might by incorrect or perhaps I am providing the multiparts in the wrong order. I include the text of the received mail as output by gmail (which renders the file correc Message-ID: <[email protected]> Subject: =?UTF-8?Q?Test_from_=E3=82=AF=E3=83=AA=E3=82=B9?= MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_0_20870565.1274154021755" ------=_Part_0_20870565.1274154021755 Content-Type: application/octet-stream Content-Transfer-Encoding: base64 Content-ID: <20100518124021763_368238_0> iVBORw0K ----- TRIMMED FOR CONCISENESS 6p1VVy4alAAAAABJRU5ErkJggg== ------=_Part_0_20870565.1274154021755 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: 7bit <html><head><title>Employees Favourite Foods</title> <style> body { font: normal 8pt arial; } th { font: bold 8pt arial; white-space: nowrap; } td { font: normal 8pt arial; white-space: nowrap; } </style></head><body> Before Image<br><img src="cid:20100518124021763_368238_0"> After Image<br><table border="0"> <tr> <th colspan="4">Employees Favourite Foods</th> </tr> <tr> <th align="left">Name</th><th align="left">Age</th><th align="left">Tel.No</th><th align="left">Fav.Food</th> </tr> <tr style="background-color:#e0e0e0"> <td>Chris</td><td>34</td><td>555-123-4567</td><td>Pancakes</td> </tr> </table></body></html> ------=_Part_0_20870565.1274154021755 Content-Type: text/plain; charset=us-ascii; name=textfile.txt Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename=textfile.txt This is a textfile with numbers counting from one to ten beneath this line: one two three four five six seven eight nine ten(no trailing carriage return) ------=_Part_0_20870565.1274154021755-- Even if you can't assist me with this, I would appreciate it if any members of the forum could forward me a (non-personal) mail that includes inline images (not external hyperlinked images though). I just need to find a working sample then I can move past this. Thanks, Chris.

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  • Hibernate Mapping Annotation Question?

    - by paddydub
    I've just started using hibernate and I'm trying to map walking distance between two coordinates into a hashmap, There can be many connections from one "FromCoordinate" to another "ToCoordinate". I'm not sure if i've implemented this correctly, What annotations do i need to map this MashMap? Thanks @Entity @Table(name = "COORDCONNECTIONS") public class CoordinateConnection implements Serializable{ private static final long serialVersionUID = -1624745319005591573L; /** auto increasing id number */ @GeneratedValue(strategy = GenerationType.IDENTITY) @Column(name = "ID") @id private int id; @Embedded public FromCoordinate fromCoord; @Embedded public ToCoordinate toCoord; HashMap<Coordinate, ArrayList<Coordinate>> coordWalkingConnections = new HashMap<Coordinate, ArrayList<Coordinate>>(); } public class FromCoordinate implements ICoordinate { @Column(name = "FROM_LAT") private double latitude; @Column(name = "FROM_LNG") private double longitude; } public class ToCoordinate implements ICoordinate { @Column(name = "TO_LAT") private double latitude; @Column(name = "TO_LNG") private double longitude; @Column(name = "DISTANCE") private double distance; } DATABASE STRUCTURE id FROM_LAT FROM_LNG TO_LAT TO_LNG Dist 1 43.352669 -6.264341 43.350012 -6.260653 0.38 2 43.352669 -6.264341 43.352669 -6.264341 0.00 3 46.352669 -6.264341 43.353373 -6.262013 0.17 4 47.352465 -6.265865 43.351290 -6.261200 0.25 5 45.452578 -6.265768 43.352788 -6.264396 0.01 6 45.452578 -6.265768 45.782788 -6.234523 0.01 ..... ... . Example HashMap for HashMap<Coordinate, ArrayList<Coordinate>> <KEY{43.352669 -6.264341}, Arraylist VALUES{(43.350012,-6.260653,0.383657), (43.352669, -6.264341, 0.000095), (43.353373, -6.262013, 0.173201)}> <KEY{47.352465 -6.265865}, Arraylist VALUES{(43.351290,-6.261200,0.258781)}> <KEY{45.452578 -6.265768}, Arraylist VALUES{(43.352788,-6.264396,0.013726),(45.782788,-6.234523,0.017726)}>

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  • Issue with multipart/form-data

    - by kbrin80
    I am not able to get values from both files and text input in a servlet when my form includes multipart/form-data. I am using the apache.commons.fileuploads for help with the uploads. Any suggestions. Also in the code below there are some things that I feel should be more efficient. Is there a better way to store these multiple files in a db. public void performTask(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) { boolean promo = false; Database db = new Database(); Homepage hp = db.getHomePageContents(); String part = ParamUtils.getStringParameter(request, "part", ""); if(part.equals("verbage")) { String txtcontent = (String)request.getParameter("txtcontent"); String promoheader = (String)request.getParameter("promoheader"); String promosubheader = (String)request.getParameter("promosubheader"); hp.setBodyText(txtcontent); hp.setPromoHeader(promoheader); hp.setPromoSubHeader(promosubheader); System.err.println(txtcontent); } else { boolean isMultipart = ServletFileUpload.isMultipartContent(request); if (!isMultipart) { } else { FileItemFactory factory = new DiskFileItemFactory(); ServletFileUpload upload = new ServletFileUpload(factory); List items = null; try { items = upload.parseRequest(request); //System.err.print(items); } catch (FileUploadException e) { e.printStackTrace(); } Iterator itr = items.iterator(); while (itr.hasNext()) { FileItem item = (FileItem) itr.next(); if(item.getFieldName().equals("mainimg1")) { if(item.getName() !="") hp.setMainImg1(item.getName()); } if(item.getFieldName().equals("mainimg2")) { if(item.getName() !="") hp.setMainImg2(item.getName()); } if(item.getFieldName().equals("mainimg3")) { if(item.getName() !="") hp.setMainImg3(item.getName()); } if(item.getFieldName().equals("promoimg1")) { promo = true; if(item.getName() !="") { hp.setPromoImg1(item.getName()); try { File savedFile = new File("/Library/resin-4.0.1/webapps/ROOT/images/promoImg1.jpg"); item.write(savedFile); //System.err.print(items); } catch (Exception e) { System.err.println(e.getMessage()); } } } if(item.getFieldName().equals("promoimg2")) { if(item.getName() !="") { hp.setPromoImg2(item.getName()); try { File savedFile = new File("/Library/resin-4.0.1/webapps/ROOT/images/promoImg2.jpg"); item.write(savedFile); //System.err.print(items); } catch (Exception e) { System.err.println(e.getMessage()); } } } if(item.getFieldName().equals("promoimg3")) { if(item.getName() !="") { hp.setPromoImg3(item.getName()); try { File savedFile = new File("/Library/resin-4.0.1/webapps/ROOT/images/promoImg3.jpg"); item.write(savedFile); //System.err.print(items); } catch (Exception e) { System.err.println(e.getMessage()); } } } System.err.println("FNAME =" + item.getFieldName() + " : " + item.getName()); if (item.isFormField()) { } else { try { if(!promo) { String itemName = item.getName(); File savedFile = new File("/Library/resin-4.0.1/webapps/ROOT/images/"+itemName); item.write(savedFile); } //System.err.print(items); } catch (Exception e) { System.err.println(e.getMessage()); } } } } } db.updateHomePageContent(hp);

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  • JPA and MySQL transaction isolation level

    - by armandino
    I have a native query that does a batch insert into a MySQL database: String sql = "insert into t1 (a, b) select x, y from t2 where x = 'foo'"; EntityTransaction tx = entityManager.getTransaction(); try { tx.begin(); int rowCount = entityManager.createNativeQuery(sql).executeUpdate(); tx.commit(); return rowCount; } catch(Exception ex) { tx.rollback(); log.error(...); } This query causes a deadlock: while it reads from t2 with insert .. select, another process tries to insert a row into t2. I don't care about the consistency of reads from t2 when doing an insert .. select and want to set the transaction isolation level to READ_UNCOMMITTED. How do I go about setting it in JPA?

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  • Will a ScheduledExecutorService create new threads as needed?

    - by Matt Ball
    I'm using Executors.newScheduledThreadPool() to create a ScheduledExecutorService, specifying the number of threads like so: int corePoolSize = 42; ScheduledExecutorService foo = Executors.newScheduledThreadPool(corePoolSize); According to the JavaDocs, the corePoolSize argument sets the number of threads to keep in the pool, even if they are idle. Does this mean that this ExecutorService implementation may create more than corePoolSize threads as needed, similar to a cached thread pool?

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