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  • Hibernate is performing unwanted SELECTs on call to saveOrUpdate

    - by digiarnie
    Let's say I have a House entity which maps to many Person entities. I then load an existing House which has 20 occupants. beginTransaction(); House house = houseDao.find(1L); commitTransaction(); Later in the code, I can then add a new Person to the House: ... List<Person> people = house.getPeople(); people.add(new Person("Dilbert")); .... When I make the call: session.saveOrUpdate(house); Hibernate performs 21 queries: 1 to SELECT the House and 20 to SELECT each existing Person in the House. I'm sure it's a small issue on my part, however, what should I do so that I can add a new Person to the house without having such a heavy hit on the database in this situation? This is all done within the same session.

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  • Oval collision detection not working properly

    - by William
    So I'm trying to implement a test where a oval can connect with a circle, but it's not working. edist = (float) Math.sqrt(Math.pow((px + ((pwidth/2) )) - (bx + (bsize/2)), 2) + Math.pow(-((py + ((pwidth/2)) ) - (bx + (bsize/2))), 2)); and here is the full code (requires Slick2D): import org.newdawn.slick.AppGameContainer; import org.newdawn.slick.BasicGame; import org.newdawn.slick.Color; import org.newdawn.slick.GameContainer; import org.newdawn.slick.Graphics; import org.newdawn.slick.Input; import org.newdawn.slick.SlickException; public class ColTest extends BasicGame{ float px = 50; float py = 50; float pheight = 50; float pwidth = 50; float bx = 200; float by = 200; float bsize = 200; float edist; float pspeed = 3; Input input; public ColTest() { super("ColTest"); } @Override public void init(GameContainer gc) throws SlickException { } @Override public void update(GameContainer gc, int delta) throws SlickException { input = gc.getInput(); try{ if(input.isKeyDown(Input.KEY_UP)) py-=pspeed; if(input.isKeyDown(Input.KEY_DOWN)) py+=pspeed; if(input.isKeyDown(Input.KEY_LEFT)) px-=pspeed; if(input.isKeyDown(Input.KEY_RIGHT)) px+=pspeed; } catch(Exception e){} } public void render(GameContainer gc, Graphics g) throws SlickException { g.setColor(new Color(255,255,255)); g.drawString("col: " + col(), 10, 10); g.drawString("edist: " + edist + " dist: " + dist, 10, 100); g.fillRect(px, py, pwidth, pheight); g.setColor(new Color(255,0,255)); g.fillOval(px, py, pwidth, pheight); g.setColor(new Color(255,255,255)); g.fillOval(200, 200, 200, 200); } public boolean col(){ edist = (float) Math.sqrt(Math.pow((px + ((pwidth/2) )) - (bx + (bsize/2)), 2) + Math.pow(-((py + ((pwidth/2)) ) - (bx + (bsize/2))), 2)); if(edist <= (bsize/2) + (px + (pwidth/2))) return true; else return false; } public float rotate(float x, float y, float ox, float oy, float a, boolean b) { float dst = (float) Math.sqrt(Math.pow(x-ox,2.0)+ Math.pow(y-oy,2.0)); float oa = (float) Math.atan2(y-oy,x-ox); if(b) return (float) Math.cos(oa + Math.toRadians(a))*dst+ox; else return (float) Math.sin(oa + Math.toRadians(a))*dst+oy; } public static void main(String[] args) throws SlickException { AppGameContainer app = new AppGameContainer( new ColTest() ); app.setShowFPS(false); app.setAlwaysRender(true); app.setTargetFrameRate(60); app.setDisplayMode(800, 600, false); app.start(); } }

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  • Connection Pool Strategy: Good, Bad or Ugly?

    - by Drew
    I'm in charge of developing and maintaining a group of Web Applications that are centered around similar data. The architecture I decided on at the time was that each application would have their own database and web-root application. Each application maintains a connection pool to its own database and a central database for shared data (logins, etc.) A co-worker has been positing that this strategy will not scale because having so many different connection pools will not be scalable and that we should refactor the database so that all of the different applications use a single central database and that any modifications that may be unique to a system will need to be reflected from that one database and then use a single pool powered by Tomcat. He has posited that there is a lot of "meta data" that goes back and forth across the network to maintain a connection pool. My understanding is that with proper tuning to use only as many connections as necessary across the different pools (low volume apps getting less connections, high volume apps getting more, etc.) that the number of pools doesn't matter compared to the number of connections or more formally that the difference in overhead required to maintain 3 pools of 10 connections is negligible compared to 1 pool of 30 connections. The reasoning behind initially breaking the systems into a one-app-one-database design was that there are likely going to be differences between the apps and that each system could make modifications on the schema as needed. Similarly, it eliminated the possibility of system data bleeding through to other apps. Unfortunately there is not strong leadership in the company to make a hard decision. Although my co-worker is backing up his worries only with vagueness, I want to make sure I understand the ramifications of multiple small databases/connections versus one large database/connection pool.

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  • JPA and aggregate functions. How do I use the result of the query?

    - by Bogdan
    Hey guys, I'm new to ORM stuff and I need some help understanding something. Let's assume I have the following standard SQL query: SELECT *, COUNT(test.testId) AS noTests FROM inspection LEFT JOIN test ON inspection.inspId = test.inspId GROUP BY inspection.inspId which I want to use in JPA. I have an Inspection entity with a one-to-many relationship to a Test entity. (an inspection has many tests) I tried writing this in JPQL: Query query = em.createQuery("SELECT insp, COUNT(???what???) FROM Inspection insp LEFT JOIN insp.testList " + "GROUP BY insp.inspId"); 1) How do I write the COUNT clause? I'd have to apply count to elements from the test table but testList is a collection, so I can't do smth like COUNT(insp.testList.testId) 2) Assuming 1 is resolved, what type of object will be returned. It will definitely not be an Inspection object... How do I use the result?

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  • user enter data to different arrays

    - by user2900469
    This is fragment of my code (arrays as you can see): double[] Price; String[] names; int[] Quantity; Price = new double[5]; names = new String[5]; Quantity = new int[5]; Price[1] = 3.10; Price[2] = 7.80; Price[3] = 0.20; names[1] = "Ballpen"; names[2] = "Notebook"; names[3] = "Envelope"; Quantity[1] = 20; Quantity[2] = 5; Quantity[3] = 140; I enter data to arrays by myself in this case. Now i want to change my code so that my program asks user for names, price and quantity (using the Scanner class). After user enter data, program keep this in three different arrays. I dont know how to transfer data from user to arrays. I would be grateful for some example code or any help.

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  • Hibernate Auto-Increment not working

    - by dharga
    I have a column in my DB that is set with Identity(1,1) and I can't get hibernate annotations to work for it. I get errors when I try to create a new record. In my entity I have the following. @GeneratedValue(strategy=GenerationType.IDENTITY, generator="native") @Column(name="SeqNo", unique=true, nullable=false) BigDecimal seqNo; But when I try to add a new record I get the following error. Cannot insert explicit value for identity column in table 'MemberSelectedOptions' when IDENTITY_INSERT is set to OFF. I don't want to set IDENTIY_INSERT to ON because I want the identity column in the db to manage the values. The SQL that is run is the following; where you can clearly see the insert. insert into dbo.MemberSelectedOptions (OptionStatusCd, EffectiveDate, TermDate, SelectionStatusDate, SysLstUpdtUserId, SysLstTrxDtm, SourceApplication, GroupId, MemberId, OptionId, SeqNo) values (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?) What am I missing?

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  • what can cause large discrepancy between minor GC time and total pause time?

    - by cxcg
    We have a latency-sensitive application, and are experiencing some GC-related pauses we don't fully understand. We occasionally have a minor GC that results in application pause times that are much longer than the reported GC time itself. Here is an example log snippet: 485377.257: [GC 485378.857: [ParNew: 105845K-621K(118016K), 0.0028070 secs] 136492K-31374K(1035520K), 0.0028720 secs] [Times: user=0.01 sys=0.00, real=1.61 secs] Total time for which application threads were stopped: 1.6032830 seconds The total pause time here is orders of magnitude longer than the reported GC time. These are isolated and occasional events: the immediately preceding and succeeding minor GC events do not show this large discrepancy. The process is running on a dedicated machine, with lots of free memory, 8 cores, running Red Hat Enterprise Linux ES Release 4 Update 8 with kernel 2.6.9-89.0.1EL-smp. We have observed this with (32 bit) JVM versions 1.6.0_13 and 1.6.0_18. We are running with these flags: -server -ea -Xms512m -Xmx512m -XX:+UseConcMarkSweepGC -XX:NewSize=128m -XX:MaxNewSize=128m -XX:+PrintGCDetails -XX:+PrintGCTimeStamps -XX:+PrintGCApplicationStoppedTime -XX:-TraceClassUnloading Can anybody offer some explanation as to what might be going on here, and/or some avenues for further investigation?

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  • Implementing Unowned relationship Google App Engine

    - by nwallman
    My question is more of a best practices question on how to implement unowned relationships with Google App Engine. I am using JDO to do my persistence and like recommended in the google docs I'm persisting my list of unowned relationships like so: @PersistenceCapable(identityType = IdentityType.APPLICATION) public class User implements Serializable, UserDetails { ... @Persistent private List<Key> groups; ... } Now I came across my predicament when I went to query that list of objects using they Key object. So when I get my list of group keys in order to actually return a list of Group objects I have to do a look up on that key to get the object. My question is what is the recommended way of doing a unowned look up on a model object? Should I have an instance of the PersistanceManagerFactory on my Model object so I can do a lookup? Should I have an instance of my GroupDAO object on my Model object so I can do a look up? Should I have a Utility to do this type of lookup? I'm new to this so I just want to know which is the best way to do this. Thanks.

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  • Batch insert mode with hibernate and oracle: seems to be dropping back to slow mode silently

    - by Chris
    I'm trying to get a batch insert working with Hibernate into Oracle, according to what i've read here: http://docs.jboss.org/hibernate/core/3.3/reference/en/html/batch.html , but with my benchmarking it doesn't seem any faster than before. Can anyone suggest a way to prove whether hibernate is using batch mode or not? I hear that there are numerous reasons why it may silently drop into normal mode (eg associations and generated ids) so is there some way to find out why it has gone non-batch? My hibernate.cfg.xml contains this line which i believe is all i need to enable batch mode: <property name="jdbc.batch_size">50</property> My insert code looks like this: List<LogEntry> entries = ..a list of 100 LogEntry data classes... Session sess = sessionFactory.getCurrentSession(); for(LogEntry e : entries) { sess.save(e); } sess.flush(); sess.clear(); My 'logentry' class has no associations, the only interesting field is the id: @Entity @Table(name="log_entries") public class LogEntry { @Id @GeneratedValue public Long id; ..other fields - strings and ints... However, since it is oracle, i believe the @GeneratedValue will use the sequence generator. And i believe that only the 'identity' generator will stop bulk inserts. So if anyone can explain why it isn't running in batch mode, or how i can find out for sure if it is or isn't in batch mode, or find out why hibernate is silently dropping back to slow mode, i'd be most grateful. Thanks

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  • How can I change jtable height at runtime

    - by wniroshan
    I hava a JFrame with multiple JPanels of similar width aligned one below other. I use one of these JPanels to display a JTable which is the last JPanel of the lot. This JPanel has a JScrollpane as a child component. This is where I try to add my table dynamically. Initial height of this JScrollpane is set to 40. I designed above template using Netbeans 6.8 Now I'm trying to add the table to the JPanel. When a button is pressed below code snippet is called. The class which includes this code extends javax.swing.JFrame class. I am expecting below code would adjust table height according to the row count and display the table. SearchTable = new JTable(RowData, DisplayNames) { @Override public boolean isCellEditable(int rowIndex, int vColIndex) { return false; } }; // if row count is less than 10 then display all the rows without a scroll bar if (SearchTable.getRowCount() < 10) { pnl_tblpanel.setPreferredSize(new Dimension(625, SearchTable.getRowHeight() * (SearchTable.getRowCount() + 4))); scr_tblholder.setPreferredSize(new Dimension(625, SearchTable.getRowHeight() * (SearchTable.getRowCount() + 4))); } else {// if row count is more than 10 display first 10 rows and add a scroll bar pnl_tblpanel.setPreferredSize(new Dimension(625, SearchTable.getRowHeight() * (10 + 2))); scr_tblholder.setAutoscrolls(true); } //pnl_tblpanel.add(scr_tblholder); scr_tblholder.setViewportView(SearchTable); //pnl_tblpanel.repaint(); pnl_tblpanel.validate(); this.validate(); //this.repaint(); pnl_tblpanel.setVisible(true); this.pack(); The table displays, but the table height is not changed according to the row count. It stays its default value. I have been trying many combinations of validate and repaint but nothing worked. (More in desperation) Can anyone shed some light on this Thank you

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  • issue of JSTL forEach iterate from arrayList

    - by Mickey
    In my code, I have used ArrayList which stores the number format like '$0.00 to $1,000,000.00' in each index of array list. while iterate in JSP through tag, its values are printing like $0.00 to $1 as a first string, 000 as a second string and 000.00 as a thrid string. but it has to print like '$0.00 to $1,000,000.00'. what will be the problem is? Thanks in advance

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  • How can I make a workspace-folder level build script visible in the Eclipse Project Explorer?

    - by Chris
    I have a number of interdependent projects in an Eclipse workspace. Eclipse manages dependencies between them within the IDE but I'm starting work on a master build script that will sit in the folder about all the projects (the workspace folder). I haven't decided on if I will use Maven, Gradle or Ant/Ivy tet, but my question is, is there a way so that I can see a build script in the workspace folder in the Project/Package explorer? Currently it only shows me projects, but assuming I decide on an Ant build, I want to be able to see the main build.xml file in this window. I've played around with settings to no avail. Is it possible? If not, should I just set up an external run configuration instead?

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  • creating and returning an array from a method

    - by Troy
    howdy, i currently have a method that checks what is around the centre item in a 3x3 grid, if what is in the 8 adjacent positions is containing what i am checking for i want to mark that square on an array with length 7 as being 1. to do this i need to create and return an array in my method, is it possible to do this?

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  • Why baseclass calls method of subclass?

    - by twlkyao
    I encounter some code like the following: BaseClass: public class BaseClass { String name = "Base"; public BaseClass() { printName(); } public void printName() { System.out.println(name + "——Base"); } } DrivedClass: public class SubClass extends BaseClass { String name = "Sub"; public SubClass() { printName(); } public void printName() { System.out.println(name + "——Sub"); } public static void main(String[] args) { new SubClass(); } } When run the code, the output is: null——Sub Sub——Sub while it should be: Base——Base Sub——Sub I wonder why the BaseClass constructor calls the SubClass method, can anybody explain this? Thanks in advance.

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  • Creating a fancy search bar with Swing components

    - by Kavon Farvardin
    I'm trying to come up with an elegant recreation of the search bar component in Thunderbird. The clear button doesn't appear until there is text in the box, so that screen-shot is a bit inaccurate. Should I use a layered pane and get some buttons to float above the box? (but then getting the text to not appear below the buttons would be hacky) Maybe just put buttons at the ends of the search bar and have it somehow blend in? Any ideas or maybe a style reconsideration is welcome, thank you.

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  • Find the class of the generic object

    - by Mgccl
    Suppose I have the following class. public class gen<T> { public gen(){ } Class<T> class(){ //something that figures out what T is. } } How can I implement the class() function without pass any additional information? What I did is here, but I have to pass a object of T into the object gen. public class gen<T> { public gen(){ } Class<T> class(T var){ return (Class<T>) var.getClass(); } }

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  • Projections.count() and Projections.countDistinct() both result in the same query

    - by Kim L
    EDIT: I've edited this post completely, so that the new description of my problem includes all the details and not only what I previously considered relevant. Maybe this new description will help to solve the problem I'm facing. I have two entity classes, Customer and CustomerGroup. The relation between customer and customer groups is ManyToMany. The customer groups are annotated in the following way in the Customer class. @Entity public class Customer { ... @ManyToMany(mappedBy = "customers", fetch = FetchType.LAZY) public Set<CustomerGroup> getCustomerGroups() { ... } ... public String getUuid() { return uuid; } ... } The customer reference in the customer groups class is annotated in the following way @Entity public class CustomerGroup { ... @ManyToMany public Set<Customer> getCustomers() { ... } ... public String getUuid() { return uuid; } ... } Note that both the CustomerGroup and Customer classes also have an UUID field. The UUID is a unique string (uniqueness is not forced in the datamodel, as you can see, it is handled as any other normal string). What I'm trying to do, is to fetch all customers which do not belong to any customer group OR the customer group is a "valid group". The validity of a customer group is defined with a list of valid UUIDs. I've created the following criteria query Criteria criteria = getSession().createCriteria(Customer.class); criteria.setProjection(Projections.countDistinct("uuid")); criteria = criteria.createCriteria("customerGroups", "groups", Criteria.LEFT_JOIN); List<String> uuids = getValidUUIDs(); Criterion criterion = Restrictions.isNull("groups.uuid"); if (uuids != null && uuids.size() > 0) { criterion = Restrictions.or(criterion, Restrictions.in( "groups.uuid", uuids)); } criteria.add(criterion); When executing the query, it will result in the following SQL query select count(*) as y0_ from Customer this_ left outer join CustomerGroup_Customer customergr3_ on this_.id=customergr3_.customers_id left outer join CustomerGroup groups1_ on customergr3_.customerGroups_id=groups1_.id where groups1_.uuid is null or groups1_.uuid in ( ?, ? ) The query is exactly what I wanted, but with one exception. Since a Customer can belong to multiple CustomerGroups, left joining the CustomerGroup will result in duplicated Customer objects. Hence the count(*) will give a false value, as it only counts how many results there are. I need to get the amount of unique customers and this I expected to achieve by using the Projections.countDistinct("uuid"); -projection. For some reason, as you can see, the projection will still result in a count(*) query instead of the expected count(distinct uuid). Replacing the projection countDistinct with just count("uuid") will result in the exactly same query. Am I doing something wrong or is this a bug? === "Problem" solved. Reason: PEBKAC (Problem Exists Between Keyboard And Chair). I had a branch in my code and didn't realize that the branch was executed. That branch used rowCount() instead of countDistinct().

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  • How to use Boolean variable in c:if

    - by Patriks
    I am using this code in jsf <c:if test="#{sV.done.booleanValue()}"> <option value="#{sV.id}" selected="selected">#{sV.text}</option> </c:if> <c:if test="#{not sV.done.booleanValue()}"> <option value="#{sV.id}">#{sV.text}</option> </c:if> sv is my class containing data (pojo), done is an Boolean variable, I want to display option tag with selected attribute if sV.done is true. But I couldn't make it. Don't know where I am wrong. Otherwise there can be something worong with c? because c:forEach was not working before some time in my case in same page. it can be the reason? Where I am wrong?

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  • javac will not compile enum, ( Windows Sun 1.6 --> OpenJDK 1.6)

    - by avgvstvs
    package com.scheduler.process; public class Process { public enum state { NOT_SUBMITTED, SUBMITTED, BLOCKED, READY, RUNNING, COMPLETED } private state currentState; public state getCurrentState() { return currentState; } public void setCurrentState(state currentState) { this.currentState = currentState; } } package com.scheduler.machine; import com.scheduler.process.Process; import com.scheduler.process.Process.state; public class Machine { com.scheduler.process.Process p = new com.scheduler.process.Process(); state s = state.READY; //fails if I don't also explicitly import Process.state p.setCurrentState(s); //says I need a declarator id after 's'... this is wrong. p.setCurrentState(state.READY); } Modified the example to try and direct to the issue. I cannot change the state on this code. Eclipse suggests importing Process.state like I had on my previous example, but this doesn't work either. This allows state s = state.READY but the call to p.setCurrentState(s); fails as does p.setCurrentState(state.READY);

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  • JPA CascadeType.ALL does not delete orphans.

    - by Paul Whelan
    I am having trouble deleting orphan nodes using JPA with the following mapping @OneToMany (cascade = CascadeType.ALL, fetch = FetchType.EAGER, mappedBy = "owner") private List<Bikes> bikes; I am having the issue of the orphaned roles hanging around the database. I can use the @org.hibernate.annotations.Cascade Hibernate specific tag but obviously I don't want to tie my solution into a hibernate implementation. Any pointers greatly appreciated.

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