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  • Injecting EntityManager Vs. EntityManagerFactory

    - by SB
    A long question, please bear with me. We are using Spring+JPA for a web application. My team is debating over injecting EntityManagerFactory in the GenericDAO(a DAO based on Generics something on the lines provided by APPFUSE, we do not use JpaDaosupport for some reason) over injecting an EntityManager. We are using "application managed persistence". The arguments against injecting a EntityManagerFactory is that its too heavy and so is not required, the EntityManager does what we need. Also, as Spring would create a new instance of a DAO for every web request(I doubt this) there are not going to be any concurrency issues as in the same EntityManager instance is shared by two threads. The argument for injecting EFM is that its a good practice over all its always good to have a handle to a factory. I am not sure which is the best approach, can someone please enlighten me? SB

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  • How to set default values to all wrong or null parameters of method?

    - by Roman
    At the moment I have this code (and I don't like it): private RenderedImage private RenderedImage getChartImage (GanttChartModel model, String title, Integer width, Integer height, String xAxisLabel, String yAxisLabel, Boolean showLegend) { if (title == null) { title = ""; } if (xAxisLabel == null) { xAxisLabel = ""; } if (yAxisLabel == null) { yAxisLabel = ""; } if (showLegend == null) { showLegend = true; } if (width == null) { width = DEFAULT_WIDTH; } if (height == null) { height = DEFAULT_HEIGHT; } ... } How can I improve it? I have some thoughts about introducing an object which will contain all these parameters as fields and then, maybe, it'll be possible to apply builder pattern. But still don't have clear vision how to implement that and I'm not sure that it's worth to be done. Any other ideas?

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  • Where's javax.servlet?

    - by egaga
    I have jdk1.6.0_13 installed, but when I try to find a javax.servlet package, or press ctrl+space in Eclipse after Servlet I cannot get anything. Where can I download this package, and why isn't it included in standard distribution for developers?

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  • how to call service inside service layer

    - by cometta
    in my service layer public class MyServiceLayerImpl{ @Autowired MyServiceInterface MyServiceLayer } if i have method inside service layer that need to call another service inside service layer. i cannot use this._method ,because, i'm using AOP for caching. In order for the caching to work, i have to use @Autowired to get the service. Therefore, is the above style ok?

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  • hibernate versioning parent entity

    - by Priit
    Consider two entities Parent and Child. Child is part of Parent's transient collection Child has a ManyToOne mapping to parent with FetchType.LAZY Both are displayed on the same form to a user. When user saves the data we first update Parent instance and then Child collection (both using merge). Now comes the tricky part. When user modifies only Child property on the form then hibernate dirty checking does not update Parent instance and thus does not increase optimistic locking version number for that entity. I would like to see situation where only Parent is versioned and every time I call merge for Parent then version is always updated even if actual update is not executed in db.

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  • How can I store large amount of data from a database to XML (memory problem)?

    - by Andrija
    First, I had a problem with getting the data from the Database, it took too much memory and failed. I've set -Xmx1500M and I'm using scrolling ResultSet so that was taken care of. Now I need to make an XML from the data, but I can't put it in one file. At the moment, I'm doing it like this: while(rs.next()){ i++; xmlStringBuilder.append("\n\t<row>"); xmlStringBuilder.append("\n\t\t<ID>" + Util.transformToHTML(rs.getInt("id")) + "</ID>"); xmlStringBuilder.append("\n\t\t<JED_ID>" + Util.transformToHTML(rs.getInt("jed_id")) + "</JED_ID>"); xmlStringBuilder.append("\n\t\t<IME_PJ>" + Util.transformToHTML(rs.getString("ime_pj")) + "</IME_PJ>"); //etc. xmlStringBuilder.append("\n\t</row>"); if (i%100000 == 0){ //stores the data to a file with the name i.xml storeKBR(xmlStringBuilder.toString(),i); xmlStringBuilder= null; xmlStringBuilder= new StringBuilder(); } and it works; I get 12 100 MB files. Now, what I'd like to do is to do is have all that data in one file (which I then compress) but if just remove the if part, I go out of memory. I thought about trying to write to a file, closing it, then opening, but that wouldn't get me much since I'd have to load the file to memory when I open it. P.S. If there's a better way to release the Builder, do let me know :)

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  • Jetty: Stopping programatically causes "1 threads could not be stopped"

    - by Ondra Žižka
    Hi, I have an embedded Jetty 6.1.26 instance. I want to shut it down by HTTP GET sent to /shutdown. So I created a JettyShutdownServlet: @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { resp.setStatus(202, "Shutting down."); resp.setContentType("text/plain"); ServletOutputStream os = resp.getOutputStream(); os.println("Shutting down."); os.close(); resp.flushBuffer(); // Stop the server. try { log.info("Shutting down the server..."); server.stop(); } catch (Exception ex) { log.error("Error when stopping Jetty server: "+ex.getMessage(), ex); } However, when I send the request, Jetty does not stop - a thread keeps hanging in org.mortbay.thread.QueuedThreadPool on the line with this.wait(): // We are idle // wait for a dispatched job synchronized (this) { if (_job==null) this.wait(getMaxIdleTimeMs()); job=_job; _job=null; } ... 2011-01-10 20:14:20,375 INFO org.mortbay.log jetty-6.1.26 2011-01-10 20:14:34,756 INFO org.mortbay.log Started [email protected]:17283 2011-01-10 20:25:40,006 INFO org.jboss.qa.mavenhoe.MavenHoeApp Shutting down the server... 2011-01-10 20:25:40,006 INFO org.mortbay.log Graceful shutdown [email protected]:17283 2011-01-10 20:25:40,006 INFO org.mortbay.log Graceful shutdown org.mortbay.jetty.servlet.Context@1672bbb{/,null} 2011-01-10 20:25:40,006 INFO org.mortbay.log Graceful shutdown org.mortbay.jetty.webapp.WebAppContext@18d30fb{/jsp,file:/home/ondra/work/Mavenhoe/trunk/target/classes/org/jboss/qa/mavenhoe/web/jsp} 2011-01-10 20:25:43,007 INFO org.mortbay.log Stopped [email protected]:17283 2011-01-10 20:25:43,009 WARN org.mortbay.log 1 threads could not be stopped 2011-01-10 20:26:43,010 INFO org.mortbay.log Shutdown hook executing 2011-01-10 20:26:43,011 INFO org.mortbay.log Shutdown hook complete It blocks for exactly one minute, then shuts down. I've added the Graceful shutdown, which should allow me to shut the server down from a servlet; However, it does not work as you can see from the log. I've solved it this way: Server server = new Server( PORT ); server.setGracefulShutdown( 3000 ); server.setStopAtShutdown(true); ... server.start(); if( server.getThreadPool() instanceof QueuedThreadPool ){ ((QueuedThreadPool) server.getThreadPool()).setMaxIdleTimeMs( 2000 ); } setMaxIdleTimeMs() needs to be called after the start(), becase the threadPool is created in start(). However, the threads are already created and waiting, so it only applies after all threads are used at least once. I don't know what else to do except some awfulness like interrupting all threads or System.exit(). Any ideas? Is there a good way? Thanks, Ondra

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  • How do I make JPA POJO classes + Netbeans forms play well together?

    - by Zak
    I started using netbeans to design forms to edit the instances of various classes I have made in a small app I am writing. Basically, the app starts, an initial set of objects is selected from the DB and presented in a list, then an item in the list can be selected for editing. When the editor comes up it has form fields for many of the data fields in the class. The problem I run into is that I have to create a controller that maps each of the data elements to the correct form element, and create an inordinate number of small conversion mapping lines of code to convert numbers into strings and set the correct element in a dropdown, then another inordinate amount of code to go back and update the underlying object with all the values from the form when the save button is clicked. My question is; is there a more directly way to make the editing of the form directly modify the contents of my class instance? I would like to be able to have a default mapping "controller" that I can configure, then override the getter/setter for a particular field if needed. Ideally, there would be standard field validation for things like phone numbers, integers, floats, zip codes, etc... I'm not averse to writing this myself, I would just like to see if it is already out there and use the right tool for the right job.

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  • Defining tokens at runtime

    - by Peter Crenshaw
    I want to write a parser for EDIFACT messages with JavaCC. My problem is that I cannot define all terminal symbols before parsing a message because at the begining of each message there is a so called "Advice Segment" ("UNA" Segment) which defines things like element seperator symbol, escape symbol, segment terminator symbol and decimal notation (e.g. '.' or ','). So I think/guess the production rules need some kind of variables which must be set at runtime during parsing. Can this be done with JavaCC and if so how? Or is there another way I am missing?

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  • Refreshing a JPA result list which is bound with a jTable

    - by exhuma
    First off, I hage to write this on my mobile. But I'll try to format it properly. In Netbeans I created a jTable and bound it's values to a JPA result set. This works great. The qery contains a param which i set in the pre-create box of the "query result" component. So just before netbeans creates the query result i write this: myQuery.setParameter("year", "1997"); This works fine. Now, I have an event handler which is supposed to change the param and display the new values in the table. So I do this: myQuery.setParameter("year", "2005"); myResultList.clear(); myResultList.addAll(myQuery.getResultList()); jTable1.updateUI(); This works, but it feels wrong to me. Note: the result set is bound to the table. So I was hoping there was something like this: myQuery.setParameter("year", "2005"); myResultList.refresh(); Is there something like this?

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  • How to sanitize log messages in Log4j to save them in database

    - by Rafael
    Hello, I'm trying to save log messages to a central database. In order to do this, I configured the following Appender in log4j's xml configuration: <appender name="DB" class="org.apache.log4j.jdbc.JDBCAppender"> <param name="URL" value="jdbc:postgresql://localhost/logging_test" /> <param name="user" value="test_user" /> <param name="password" value="test_password" /> <param name="sql" value="INSERT INTO log_messages ( log_level, message, log_date ) VALUES ( '%p', '%m', '%d{yyyy-MM-dd HH:mm:ss}' )" /> </appender> This works fine, except some of the messages contain ', and then the appender fails. Is there an easy way to do this?

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  • Can you return an array from a JAX-WS @WebMethod?

    - by LES2
    I'm pretty sure you can, but in addition to answering the question in the title, could you also explain the pros, cons, caveats, if any, to doing so? I know that you can't return a List, Set, Collection, Map, or any interface, from a WebMethod (which is stupid, IMO, but I don't know what the design reasons were should I should probably withhold judgment). Thanks for any advice. -- LES

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  • How to use an IN clause in iBATIS?

    - by furtelwart
    I'm using iBATIS to create select statements. Now I would like to implement the following SQL statement with iBATIS: SELECT * FROM table WHERE col1 IN ('value1', 'value2'); With the following approach, the statement is not prepared correctly and no result returns: SELECT * FROM table WHERE col1 IN #listOfValues#; iBATIS seems to restructure this list and tries to interpret it as a string. How can I use the IN clause correctly?

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  • Comparing two Objects which implement the same interface for equality / equivalence - Design help

    - by gav
    Hi All, I have an interface and two objects implementing that interface, massively simplied; public interface MyInterface { public int getId(); public int getName(); ... } public class A implements MyInterface { ... } public class B implements MyInterface { ... } We are migrating from using one implementation to the other but I need to check that the objects of type B that are generated are equivalent to those of type A. Specifically I mean that for all of the interface methods an object of Type A and Type B will return the same value (I'm just checking my code for generating this objects is correct). How would you go about this? Map<String, MyInterface> oldGeneratedObjects = getOldGeneratedObjects(); Map<String, MyInterface> newGeneratedObjects = getNewGeneratedObjects(); // TODO: Establish that for each Key the Values in the two maps return equivalent values. I'm looking for good coding practices and style here. I appreciate that I could just iterate through one key set pulling out both objects which should be equivalent and then just call all the methods and compare, I'm just thinking there may be a cleaner, more extensible way and I'm interested to learn what options there might be. Would it be appropriate / possible / advised to override equals or implement Comparable? Thanks in advance, Gavin

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  • Problem with 2 levels of inheritance in hibernate mapping

    - by Seth
    Here's my class structure: class A class B extends A class C extends A class D extends C class E extends C And here are my mappings (class bodies omitted for brevity): Class A: @Entity @Inheritance(strategy=InheritanceType.SINGLE_TABLE) @MappedSuperclass @DiscriminatorColumn( name="className", discriminatorType=DiscriminatorType.STRING ) @ForceDiscriminator public abstract class A Class B: @Entity @DiscriminatorValue("B") public class B extends A Class C: @Entity @DiscriminatorValue("C") @MappedSuperclass @DiscriminatorColumn( name="cType", discriminatorType=DiscriminatorType.STRING ) @ForceDiscriminator public abstract class C extends A Class D: @Entity @DiscriminatorValue("D") public class D extends C Class E: @Entity @DiscriminatorValue("E") public class E extends C I've got a class F that contains a set of A: @Entity public class F { ... @OneToMany(fetch=FetchType.LAZY, cascade=CascadeType.ALL) @JoinTable( name="F_A", joinColumns = @JoinColumn(name="A_ID"), inverseJoinColumns = @JoinColumn(name="F_ID") ) private Set<A> aSet = new HashSet<A>(); ... The problem is that whenever I add a new E instance to aSet and then call session.saveOrUpdate(fInstance), hibernate saves with "A" as the discrimiator string. When I try to access the aSet in the F instance, I get the following exception (full stacktrace ommitted for brevity): org.hibernate.InstantiationException: Cannot instantiate abstract class or interface: path.to.class.A Am I mapping the classes incorrectly? How am I supposed to map multiple levels of inheritance? Thanks for the help!

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  • calculate business days including holidays

    - by ran
    i need to calculate the business days between two dates. ex : we have holiday(in USA) on july4th. so if my dates are date1 = 07/03/2012 date2 = 07/06/2012 no of business days b/w these dates should be 1 since july4th is holiday. i have a below method to calclulate the business days which will only counts week ends but not holidays. is there any way to calculate holidays also....please help me on this. public static int getWorkingDaysBetweenTwoDates(Date startDate, Date endDate) { Calendar startCal; Calendar endCal; startCal = Calendar.getInstance(); startCal.setTime(startDate); endCal = Calendar.getInstance(); endCal.setTime(endDate); int workDays = 0; //Return 0 if start and end are the same if (startCal.getTimeInMillis() == endCal.getTimeInMillis()) { return 0; } if (startCal.getTimeInMillis() > endCal.getTimeInMillis()) { startCal.setTime(endDate); endCal.setTime(startDate); } do { startCal.add(Calendar.DAY_OF_MONTH, 1); if (startCal.get(Calendar.DAY_OF_WEEK) != Calendar.SATURDAY && startCal.get(Calendar.DAY_OF_WEEK) != Calendar.SUNDAY) { ++workDays; } } while (startCal.getTimeInMillis() < endCal.getTimeInMillis()); return workDays; }

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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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  • tomcat session replication without multicast

    - by Andreas Petersson
    i am planning to use 2 dedicated root servers rented at a hosting provider. those machines will run tomcat 6 in a cluster. if i will add additional machines later on - it is unlikely that they will be accessible with multicast, because they will be located in different subnets. is it possible to run tomcat without multicast? all tutorials for tomcat 6 clustering include multicast heartbeat. are there any alternatives to SimpleTcpCluster? or are other alternatives more appropriate in this situation?

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  • ANDROID : how to get value stored in ArrayList<HashMap<key,value>>?

    - by Roshni Kyada
    I have ArrayList. At another activity i want to access all values stored in ArrayList. I tried following code. ArrayList<HashMap<String, String>> mylist = new ArrayList<HashMap<String, String>>(); for(Hashmap<String, String> map: mylist) { for(Entry<String, String> mapEntry: map) { String key = mapEntry.getKey(); String value = mapEntry.getValue(); } } but it shows an error at for(Entry mapEntry: map) that it only interate over Array.

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  • BFS Shortest Path: Edge weight either 1 or 2

    - by Hackster
    I am trying to implement a shortest path algorithm using BFS. That is I am trying to find the shortest path from a specified vertex to every other vertex. However, its a special case where all edge weights are either 1 or 2. I know it could be done with Dijkstra's algorithm but I must use Breadth First Search. So far I have a working version of BFS that searches first for a vertex connected with an edge of weight 1. If it cannot find it, then returns a vertex connected with an edge of weight 2. After thinking about it, this is not the correct way to find the shortest path. The problem is I cannot think of any reasoning why BFS would work with weights 1 or 2, as opposed to any weight. Here is the code: public void addEdge(int start, int end, int weight) { adjMat[start][end] = 1; adjMat[end][start] = 1; edge_weight[start][end] = weight; edge_weight[end][start] = weight; } // ------------------------------------------------------------- public void bfs() // breadth-first search { // begin at vertex 0 vertexList[0].wasVisited = true; // mark it displayVertex(0); // display it theQueue.insert(0); // insert at tail int v2; while( !theQueue.isEmpty() ) // until queue empty, { int v1 = theQueue.remove(); // remove vertex at head // until it has no unvisited neighbors while( (v2=getAdjUnvisitedVertex(v1)) != -1 ){// get one, vertexList[v2].wasVisited = true; // mark it displayVertex(v2); // display it theQueue.insert(v2); // insert it } } // end while(queue not empty) // queue is empty, so we're done for(int j=0; j<nVerts; j++) // reset flags vertexList[j].wasVisited = false; } // end bfs() // ------------------------------------------------------------- // returns an unvisited vertex adj to v -- ****WITH WEIGHT 1**** public int getAdjUnvisitedVertex(int v) { for (int j = 0; j < nVerts; j++) if (adjMat[v][j] == 1 && vertexList[j].wasVisited == false && edge_weight[v][j] == 1){ //System.out.println("Vertex found with 1:"+ vertexList[j].label); return j; } for (int k = 0; k < nVerts; k++) if (adjMat[v][k] == 1 && vertexList[k].wasVisited == false && edge_weight[v][k] == 2){ //System.out.println("Vertex found with 2:"+vertexList[k].label); return k; } return -1; } // end getAdjUnvisitedVertex() // ------------------------------------------------------------- } //////////////////////////////////////////////////////////////// public class BFS{ public static void main(String[] args) { Graph theGraph = new Graph(); theGraph.addVertex('A'); // 0 (start for bfs) theGraph.addVertex('B'); // 1 theGraph.addVertex('C'); // 2 theGraph.addEdge(0, 1,2); // AB theGraph.addEdge(1, 2,1); // BC theGraph.addEdge(2, 0,1); // AD System.out.print("Visits: "); theGraph.bfs(); // breadth-first search System.out.println(); } // end main() } The problem then is, that I don't know why BFS can work for the shortest path problem with edges of weight 1 or 2 as opposed to any edges of any weight. Any help is appreciated. Thanks!

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  • Android - Parsing XML with XPath

    - by Ruben Deig Ramos
    First of all, thanks to all the people who's going to spend a little time on this question. Second, sorry for my english (not my first language! :D). Well, here is my problem. I'm learning Android and I'm making an app which uses a XML file to store some info. I have no problem creating the file, but trying to read de XML tags with XPath (DOM, XMLPullParser, etc. only gave me problems) I've been able to read, at least, the first one. Let's see the code. Here is the XML file the app generates: <dispositivo> <id>111</id> <nombre>Name</nombre> <intervalo>300</intervalo> </dispositivo> And here is the function which reads the XML file: private void leerXML() { try { XPathFactory factory=XPathFactory.newInstance(); XPath xPath=factory.newXPath(); // Introducimos XML en memoria File xmlDocument = new File("/data/data/com.example.gps/files/devloc_cfg.xml"); InputSource inputSource = new InputSource(new FileInputStream(xmlDocument)); // Definimos expresiones para encontrar valor. XPathExpression tag_id = xPath.compile("/dispositivo/id"); String valor_id = tag_id.evaluate(inputSource); id=valor_id; XPathExpression tag_nombre = xPath.compile("/dispositivo/nombre"); String valor_nombre = tag_nombre.evaluate(inputSource); nombre=valor_nombre; } catch (Exception e) { e.printStackTrace(); } } The app gets correctly the id value and shows it on the screen ("id" and "nombre" variables are assigned to a TextView each one), but the "nombre" is not working. What should I change? :) Thanks for all your time and help. This site is quite helpful! PD: I've been searching for a response on the whole site but didn't found any.

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  • Spring security and Struts 2

    - by Thanksforfish
    I have a struts2 action with an @Secured({"ROLE_ADMIN"}) to secure the execute method. In the execute method i assign a message to a member variable of the action, then return SUCCESS and end up on the jsp page. On the page I retrieve the actions member variable with <sroperty. private String greeting; public String execute() throws Exception { this.greeting="Hello"; return SUCCESS; } // getters and setters for greeting ... <s:property value="greeting" /> The problem is when the secured annotation is present the jsp shows nothing for the member variable but when @Secured is removed the whole thing behaves properly and shows the message that was set into the member variable. It appears that the actual security is working ok but when enabled via the annotation the member variable (or maybe the instance of the action) is not making its way onto the value stack. I cant see any error messages.

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