Search Results

Search found 33297 results on 1332 pages for 'java java ee'.

Page 830/1332 | < Previous Page | 826 827 828 829 830 831 832 833 834 835 836 837  | Next Page >

  • How to copy generically superclass instances to subclass instances?

    - by gerry
    Hi @all, I have a class hierarchy / inheritance like this: public class A { private String name; // with getters & setters public void doAWithName(){ ... } } public class B extends A { public void doBWithName(){ // a differnt implementation to what I do in class A } } public class C extends B { public void doCWithName(){ // a differnt implementation to what I do in class A and B } } So at one time there is a instance of class A with the initialized field "name". Later I want this instance of A get wrapped into instance of B or C. So the superclasses should be get wrapped with a subclass! How can I make this most efficent with respect to DRY? I've thought about a constructor that does some copying with the getters/setters. But in this case I have to repeat myself - and this doesn't respect anymore to my initial requirement of DRY! So, how can I warp A to B by just initializing B's new fields (with default values) and delegating the rest to a method in A (which knows more than B about which fields of A should be accessed...). In the same way: If A should be wrapped into C only a method in c should init C's 'new' fields, delegate to B's wrap method (which therefore inits B's 'new' fields in C) and at last B delegates to A which copies it's fields to the fields of C). So in the end I have a new instance of C which has the values of A wrapped (and some default init values to the fields which the inheritance hierarchy has added).

    Read the article

  • How significant are JPA lazy loading performance benefits?

    - by Robert
    I understand that this is highly specific to the concrete application, but I'm just wondering what's the general opinion, or at least some personal experiences on the issue. I have an aversion towards the 'open session in view' pattern, so to avoid it, I'm thinking about simply fetching everything small eagerly, and using queries in the service layer to fetch larger stuff. Has anyone used this and regretted it? And is there maybe some elegant solution to lazy loading in the view layer that I'm not aware of?

    Read the article

  • Hibernate session method to update object

    - by EugeneP
    I need this roadmap of a Hibernate managed object instance. First, I create an instance with initial properties and persist this object in a db. Then session associated with this object is closed. But still, I serialize my object and on the next step deserialize it, invoke some setters, and again, I need to update what changed in a database. What methods of Hibernate session should I use? persist() or save() on the first step and saveOrUpdate() on the second? In fact I see that saveOrUpdate() can be used on each step. What would you recommend?

    Read the article

  • Change TrayIcon Tooltip from ProgressMonitorDialog

    - by Raven
    Hello, i am using the Eclipse RCP trayitem, which is described in Vogellas tutorials here: http://www.vogella.de/articles/RichClientPlatform/article.html#systemtray The requirement now is not only to show the name of the app in the tooltip but also a percentage while doing lengthy operations. I understand that the trayitem attribute is a private from ApplicationWorkbenchWindowAdvisor, so I added a getter and setter method. The only thing missing is a possibility to access the trayitem instance from my ProgressMonitorDialog instance. Can you tell me, how you would solve this puzzle? Thanks

    Read the article

  • how to Solve the "Digg" problem in MongoDB

    - by user193116
    A while back,a Digg developer had posted this blog ,"http://about.digg.com/blog/looking-future-cassandra", where the he described one of the issues that were not optimally solved in MySQL. This was cited as one of the reasons for their move to Cassandra. I have been playing with MongoDB and I would like to understand how to implement the MongoDB collections for this problem From the article, the schema for this information in MySQL : CREATE TABLE Diggs ( id INT(11), itemid INT(11), userid INT(11), digdate DATETIME, PRIMARY KEY (id), KEY user (userid), KEY item (itemid) ) ENGINE=InnoDB DEFAULT CHARSET=utf8; CREATE TABLE Friends ( id INT(10) AUTO_INCREMENT, userid INT(10), username VARCHAR(15), friendid INT(10), friendname VARCHAR(15), mutual TINYINT(1), date_created DATETIME, PRIMARY KEY (id), UNIQUE KEY Friend_unique (userid,friendid), KEY Friend_friend (friendid) ) ENGINE=InnoDB DEFAULT CHARSET=utf8; This problem is ubiquitous in social networking scenario implementation. People befriend a lot of people and they in turn digg a lot of things. Quickly showing a user what his/her friends are up to is very critical. I understand that several blogs have since then provided a pure RDBMs solution with indexes for this issue; however I am curious as to how this could be solved in MongoDB.

    Read the article

  • Handling multiple exceptions

    - by the-banana-king
    Hi there, I have written a class which loads configuration objects of my application and keeps track of them so that I can easily write out changes or reload the whole configuration at once with a single method call. However, each configuration object might potentially throw an exception when doing IO, yet I do not want those errors to cancel the overall process so that the other objects are still given a chance to reload/write. Therefore I collect all exceptions which are thrown while iterating over the objects and store them in a super-exception, which is thrown after the loop, since each exception must still be handled and someone has to be notified of what exactly went wrong. However, that approach looks a bit odd to me. Someone out there with a cleaner solution? Here is some code of the mentioned class: public synchronized void store() throws MultipleCauseException { MultipleCauseException me = new MultipleCauseException("unable to store some resources"); for(Resource resource : this.resources.values()) { try { resource.store(); } catch(StoreException e) { me.addCause(e); } } if(me.hasCauses()) throw me; }

    Read the article

  • JPA2 adding referential contraint to table complicates criteria query with lazy fetch, need advice

    - by Quaternion
    Following is a lot of writing for what I feel is a pretty simple issue. Root of issue is my ignorance, not looking so much for code but advice. Table: Ininvhst (Inventory-schema inventory history) column ihtran (inventory history transfer code) using an old entity mapping I have: @Basic(optional = false) @Column(name = "IHTRAN") private String ihtran; ihtran is really a foreign key to table Intrnmst ("Inventory Transfer Master" which contains a list of "transfer codes"). This was not expressed in the database so placed a referential constraint on Ininvhst re-generating JPA2 entity classes produced: @JoinColumn(name = "IHTRAN", referencedColumnName = "TMCODE", nullable = false) @ManyToOne(optional = false) private Intrnmst intrnmst; Now previously I was using JPA2 to select the records/(Ininvhst entities) from the Ininvhst table where "ihtran" was one of a set of values. I used in.value() to do this... here is a snippet: cq = cb.createQuery(Ininvhst.class); ... In in = cb.in(transactionType); //Get in expression for transacton types for (String s : transactionTypes) { //has a value in = in.value(s);//check if the strings we are looking for exist in the transfer master } predicateList.add(in); My issue is that the Ininvhst used to contain a string called ihtran but now it contains Ininvhst... So I now need a path expression: this.predicateList = new ArrayList<Predicate>(); if (transactionTypes != null && transactionTypes.size() > 0) { //list of strings has some values Path<Intrnmst> intrnmst = root.get(Ininvhst_.intrnmst); //get transfermaster from Ininvhst Path<String> transactionType = intrnmst.get(Intrnmst_.tmcode); //get transaction types from transfer master In<String> in = cb.in(transactionType); //Get in expression for transacton types for (String s : transactionTypes) { //has a value in = in.value(s);//check if the strings we are looking for exist in the transfer master } predicateList.add(in); } Can I add ihtran back into the entity along with a join column that is both references "IHTRAN"? Or should I use a projection to somehow return Ininvhst along with the ihtran string which is now part of the Intrnmst entity. Or should I use a projection to return Ininvhst and somehow limit Intrnmst just just the ihtran string. Further information: I am using the resulting list of selected Ininvhst objects in a web application, the class which contains the list of Ininvhst objects is transformed into a json object. There are probably quite a few serialization methods that would navigate the object graph the problem is that my current fetch strategy is lazy so it hits the join entity (Intrnmst intrnmst) and there is no Entity Manager available at that point. At this point I have prevented the object from serializing the join column but now I am missing a critical piece of data. I think I've said too much but not knowing enough I don't know what you JPA experts need. What I would like is my original object to have both a string object and be able to join on the same column (ihtran) and have it as a string too, but if this isn't possible or advisable I want to hear what I should do and why. Pseudo code/English is more than fine.

    Read the article

  • Where to handle fatal exceptions

    - by Stephen Swensen
    I am considering a design where all fatal exceptions will be handled using a custom UncaughtExceptionHandler in a Swing application. This will include unanticipated RuntimeExceptions but also custom exceptions which are thrown when critical resources are unavailable or otherwise fail (e.g. a settings file not found, or a server communication error). The UncaughtExceptionHandler will do different things depending on the specific custom exception (and one thing for all the unanticipated), but in all cases the application will show the user an error message and exit. The alternative would be to keep the UncaughtExceptionHandler for all unanticipated exceptions, but handle all other fatal scenarios close to their origin. Is the design I'm considering sound, or should I use the alternative?

    Read the article

  • Write problem - lossing the original data

    - by John
    Every time I write to the text file I will lose the original data, how can I read the file and enter the data in the empty line or the next line which is empty? public void writeToFile() { try { output = new Formatter(myFile); } catch(SecurityException securityException) { System.err.println("Error creating file"); System.exit(1); } catch(FileNotFoundException fileNotFoundException) { System.err.println("Error creating file"); System.exit(1); } Scanner scanner = new Scanner (System.in); String number = ""; String name = ""; System.out.println("Please enter number:"); number = scanner.next(); System.out.println("Please enter name:"); name = scanner.next(); output.format("%s,%s \r\n", number, name); output.close(); }

    Read the article

  • How to reference an embedded JCA resource adapater

    - by cg
    For our current J2EE project based on JBoss, we need to interface with a remote system using message driven beans and a JCA resource adapter provided as a RAR file by a third party. I would like to package and deploy the entire project as an EAR file to our JBoss server. Most notably, the RAR file should be embedded within the EAR file and not be deployed globally. All of this is working fine so far, but I'm not particularly happy with the way the RAR file is referenced. The jboss.xml packaged with the MDB for example, currently looks like this: <jboss> <enterprise-beans> <message-driven> <ejb-name>testBean1</ejb-name> <resource-adapter-name>test1.ear#thirdparty-1.0.rar</resource-adapter-name> </message-driven> </enterprise-beans> </jboss> While this is generally working fine, it will break when the EAR file is renamed to "test2.ear". Is there a way to reference the embedded RAR file without hard-coding the containing archive's name?

    Read the article

  • Check if there are any repeated elements in an array recursively

    - by devoured elysium
    I have to find recursively if there is any repeated element in an integer array v. The method must have the following signature: boolean hasRepeatedElements(int[] v) I can't see any way of doing that recursively without having to define another method or at least another overload to this method (one that takes for example the element to go after or something). At first I thought about checking for the current v if there is some element equal to the first element, then creating a new array with L-1 elements etc but that seems rather inefficient. Is it the only way? Am I missing here something?

    Read the article

  • Concurrent Programming:Should I write a sequential program first, then add thread safety?

    - by evthim
    I'm working on a project where we have to create a number of threads(actual number will be inputted in by testers (TA's)). I'm having trouble not only with the programming but also with the design, I can't wrap my head around all of the threads that will be invoked and where I might cause errors. The project is due soon so I don't want to waste time on this if it'll actually set me back, but I was wondering if I should write the program like only one thread will be running and everything should be sequential and then later go back and try to add the thread safety parts of the code? Would that take twice the original amount of time? Project Description: Note:I'm going to be as vague as possible so I don't violate any honor codes, sorry :( your program should accept n number of objectA threads, m number of objectB threads, and r number of objectC objectB threads interact with code in objectA. objectA threads interact with code in objectB and objectC objectB and objectC don't directly interact, but do so indirectly through objectA -ex: objectB needs something from objectA. objectA gets the result for that something by calling objectC my confusion stems mostly from the fact that all of this interactions will be done by m+n threads and there are various restrictions throughout the descriptions, like objectB can request something from objectA, and objectA has to wait for objectC to finish that something before returning it to objectB. Also each objectA thread can only work on one instruction from objectB at a time, etc. etc. I just want to know if I write the code so that there is only 1 objectA, 1 objectB and 1 object C, can I go back and easily modify it so that those 1's can be changed to m, n and r? Sorry again, if my description is a little bit confusing.

    Read the article

  • HIbernate query language problem.....

    - by mslatf
    I have a Project class that has a Set of userstories called userStories12many. I'm having troubles trying to get the project that has a certain userstory in its set getComponent(int userStoryID) I think im on the right track but i dont know what i did wrong public Projects getComponent(int userStoryID) { Session session = SessionFactoryHelper.getSessionFactory() .getCurrentSession(); session.beginTransaction(); List<Projects> compo = session.createQuery("select p " + "from Projects as p inner join fetch p.userStories12many as u " + "where u.storyId='" + userStoryID + "'").list(); session.getTransaction().commit(); return compo.get(0); }

    Read the article

  • GWT: What is the way to handle Click on GWT FlowPanel

    - by shaman.sir
    May be a dumb question, but GWT FlowPanel (raw div element) does not provides something to handle a mouseclick/mousemovement on it. Overriding onBrowserEvent do not works either. If setting onclick event using native JavaScript (need to specify positive height before, 'div' have a height of 0 if not specified), then catching these events is working properly. Is there a way to do it without using JSNI?

    Read the article

  • Getting 404 when attempting to POST file to Google Cloud Storage from service account

    - by klactose
    I'm wondering if anyone can tell me the proper syntax & formatting for a service account to send a POST Object to bucket request? I'm attempting it programmatically using the HttpComponents library. I manage to get a token from my GoogleCredential, but every time I construct the POST request, I get: HTTP/1.1 403 Forbidden <?xml version='1.0' encoding='UTF-8'?><Error><Code>AccessDenied</Code><Message>Access denied.</Message><Detailsbucket-name</Details></Error The Google documentation that describes the request methods, mentions posting using html forms, but I'm hoping that wasn't suggesting the ONLY way to get the job done. I know that HttpComponents has a way to explicitly create form data by using UrlEncodedFormEntity, but it doesn't support multipart data. Which is why I went with using the MultipartEntity class. My code is below: MultipartEntity entity = new MultipartEntity( HttpMultipartMode.BROWSER_COMPATIBLE ); String token = credential.getAccessToken(); entity.addPart("Authorization", new StringBody("OAuth " + token)); String date = formatDate(new Date()); entity.addPart("Date", new StringBody(date)); entity.addPart("Content-Encoding", new StringBody("UTF-8")); entity.addPart("Content-Type", new StringBody("multipart/form-data")); entity.addPart("bucket", new StringBody(bucket)); entity.addPart("key", new StringBody("fileName")); entity.addPart("success_action_redirect", new StringBody("/storage")); File uploadFile = new File("pathToFile"); FileBody fileBody = new FileBody(uploadFile, "text/xml"); entity.addPart("file", fileBody); httppost.setEntity(entity); System.out.println("Posting URI = "+httppost.toString()); HttpResponse response = client.execute(httppost); HttpEntity resp_entity = response.getEntity(); As I mentioned, I am able to get an actual token, so I'm pretty sure the problem is in how I've formed the request as opposed to not being properly authenticated. Keep in mind: This is being performed by a service account. Which means that it does have Read/Write access Thanks for reading, and I appreciate any help!

    Read the article

  • Meaning of the "Unloading class" messages

    - by elec
    Anyone can explain why the lines below appear in the output console at runtime ? (one possible answer would be full permGen, but this can be ruled out since the program only uses 24MB out of the max100MB available in PermGen) [Unloading class sun.reflect.GeneratedSerializationConstructorAccessor28] [Unloading class sun.reflect.GeneratedSerializationConstructorAccessor14] [Unloading class sun.reflect.GeneratedSerializationConstructorAccessor4] [Unloading class sun.reflect.GeneratedMethodAccessor5] [Unloading class sun.reflect.GeneratedSerializationConstructorAccessor38] [Unloading class sun.reflect.GeneratedSerializationConstructorAccessor36] [Unloading class sun.reflect.GeneratedSerializationConstructorAccessor22] [Unloading class sun.reflect.GeneratedSerializationConstructorAccessor8] [Unloading class sun.reflect.GeneratedSerializationConstructorAccessor39] [Unloading class sun.reflect.GeneratedSerializationConstructorAccessor16] [Unloading class sun.reflect.GeneratedSerializationConstructorAccessor2] [Unloading class sun.reflect.GeneratedConstructorAccessor1] The program runs with the following params: -Xmx160M -XX:MaxPermSize=96M -XX:PermSize=96M -XX:+UseConcMarkSweepGC -XX:+UseParNewGC -XX:+PrintGCTaskTimeStamps -XX:+PrintHeapAtGC -XX:+PrintTenuringDistribution -XX:+PrintGCDetails -XX:+PrintGCDateStamps -XX:+PrintGCTimeStamps -verbose:gc -Xloggc:/logs/gc.log There's plenty of space in the heap and in permGen.

    Read the article

  • Displaying NON-ASCII Characters using HttpClient

    - by Abdullah Gheith
    So, i am using this code to get the whole HTML of a website. But i dont seem to get non-ascii characters with me. all i get is diamonds with question mark. characters like this: å, appears like this: ? I doubt its because of the charset, what could it then be? Log.e("HTML", "henter htmlen.."); String url = "http://beep.tv2.dk"; HttpClient client = new DefaultHttpClient(); client.getParams().setParameter(CoreProtocolPNames.PROTOCOL_VERSION, HttpVersion.HTTP_1_1); client.getParams().setParameter(CoreProtocolPNames.HTTP_ELEMENT_CHARSET, "UTF-8"); HttpGet request = new HttpGet(url); HttpResponse response = client.execute(request); Header h = HeaderValueFormatter response.addHeader(header) String html = ""; InputStream in = response.getEntity().getContent(); BufferedReader reader = new BufferedReader(new InputStreamReader(in)); StringBuilder str = new StringBuilder(); String line = null; while((line = reader.readLine()) != null) { str.append(line); } in.close(); //b = false; html = str.toString();

    Read the article

  • how to import other schema jars when using the scomp tool

    - by MikeJiang
    there is a huge amount of xml schemas for the business, some of them are common types like Money.xsd, Address.xsd, etc, while others are business specific like Customer.xsd, ShippingOrder.xsd, etc. So I decide to compile these schemas into 2 jars, one is commonbeans.jar, the other is businessbeans.jar. I've separated them into different folders. to build the commonbeans.jar is simple, just run "scomp -out commonbeans.jar ....\common*.xsd"; while run "scomp -out businessbeans.jar ....\business*.xsd" is a different story, there are errors say can't find those common types, and run "scomp -out businessbeans.jar ....\business*.xsd ....\business*.xsd" will blindly duplicate all the common types into the businessbeans.jar. so is there any way to link the commonbeans.jar when compile those busimess schemas, maybe something like "scomp -out businessbeans.jar ....\business*.xsd commonbeans.jar". I hope my poor english has expressed my issue!

    Read the article

  • save managed bean to notes document

    - by Ove Stoerholt
    In a managed bean you have fields, and the fields have getters and setters. But I also need to save values back to, in this case, a Notes profile document. So I have a loadProfileDocument and a saveProfileDocument method. I was thinking of using the bean in the application scope. How do I make sure the profile document is saved? Do I have to call the saveProfileDocument from the setter? Do I call the saveProfileDocument() explisitly? Could I use a destructor (finalize)? Or what...???...

    Read the article

  • Threadsafe way of exposing keySet()

    - by Jake
    This must be a fairly common occurrence where I have a map and wish to thread-safely expose its key set: public MyClass { Map<String,String> map = // ... public final Set<String> keys() { // returns key set } } Now, if my "map" is not thread-safe, this is not safe: public final Set<String> keys() { return map.keySet(); } And neither is: public final Set<String> keys() { return Collections.unmodifiableSet(map.keySet()); } So I need to create a copy, such as: public final Set<String> keys() { return new HashSet(map.keySet()); } However, this doesn't seem safe either because that constructor traverses the elements of the parameter and add()s them. So while this copying is going on, a ConcurrentModificationException can happen. So then: public final Set<String> keys() { synchronized(map) { return new HashSet(map.keySet()); } } seems like the solution. Does this look right?

    Read the article

< Previous Page | 826 827 828 829 830 831 832 833 834 835 836 837  | Next Page >