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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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  • Making Eclipse behave like Visual Studio

    - by FlySwat
    I'm doing some Android dev, and I much prefer Visual Studio, but I'll have to use Eclipse for this. Has anyone made a tool that switches Eclipse to look and behave more like visual studio? I mainly can't stand its clippyesqe suggestions on how I should program (Yes, I know I have not yet used that private field! Thanks Eclipse!), or its incredibly lousy intellisense. For example, in eclipse, if I don't type "this" first, its intellisense won't realize I want to look for locally scoped members. Also, the TAB to complete VS convention is drilled into my head, and Eclipse is ENTER to complete, I could switch everything by hand but that would take hours, and I was hoping someone had some sort of theme or something that has already done it :)

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  • 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.

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  • correct way of initializing variables

    - by OVERTONE
    ok this is just a shot in the dark but it may be the cause of most of the errors ive gotten. when your initializing something. lets say a smal swing program. would it go liek this variables here { private Jlist contactList; String [] contactArray; ArrayList <String> contactArrayList; ResultSet namesList constructor here public whatever() { GridLayout aGrid = new GridLayout(2,2,10,10); contact1 = new String(); contact2 = new String(); contact3 = new String(); contactArrayList = new ArrayList<String>(); // is something supposed too go in the () of this JList? contactList = new JList(); contactArray = new String[5]; from1 =new JLabel ("From: " + contactArray[1]); gridlayout.add(components)// theres too many components to write onto SO. } // methods here public void fillContactsGui() { createConnection(); ArrayList<String> contactsArrayList = new ArrayList<String>(); while (namesList.next()) { contactArrayList.add(namesList.getString(1)); ContactArray[1] = namesList[1]; } } i know this is probably a huge beginner question but this is the code ive gotten used too. im initializing thigns three and fours times without meaning too because im not sure where they gp. can anyone shed some light on this? p.s. sorry for the messy sample code. i done my best.

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  • How can I load a property lazily in JDO (on Google App Engine)?

    - by luciano
    I have this code in one of my @PersistenceCapable classes: @Persistent private Blob data; The Blob can be quite big, so I'd like to load it lazily since most of the times I don't need it. How can I annotate that property to avoid immediate loading? I could create another class that contains the Blob alone and then use a lazy one-to-one, but I'd like to solve this with annotations.

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  • Add a listener inside or outside get method

    - by James P.
    I'm learning Swing and have composed an interface using a series of get methods to add components. Is it a good practise to add a Listener inside a get method as follows? I'd like to make things as decoupled as possible. private JButton getConnectButton() { if (connectButton == null) { connectButton = new JButton(); connectButton.setText("Connect"); connectButton.setSize(new Dimension(81, 16)); connectButton.setLocation(new Point(410, 5)); connectButton.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { // actionPerformed code goes here } }); } return connectButton; }

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  • JBoss envers and huge audit tables

    - by LeChe
    All, I am auditing my JEE application with JBoss Evers and the nature of my application causes the audit table to grow very fast. The historic data is queried infrequently and access time is not really an issue, apart from the data from the last week. This data IS queried frequently and access needs to be fast. Ideally, I would split the data and distribute it over two tables, with the older data in compressed format. Unfortunately, Envers does not allow spreading data over multiple tables as far as I can tell from the docs. Does somebody have any idea what would be the best way to achieve this (if possible while still using Envers)? Cheers, LeChe

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  • Problem in setting backgound color to my TreeCellRenderer

    - by Sunil Kumar Sahoo
    Hi I have cretaed my own renderer. I want the back ground should be blue. I have set background color as blue also. But I donot know what is tha problem that the background color of my renderer always seems to be white. I have post the code. please help where I am wrong so that the background color becomes white. class CheckTreeCellRenderer extends JPanel implements TreeCellRenderer { private CheckTreeSelectionModel selectionModel; private MyRenderer delegate; private TristateCheckBox checkBox = new TristateCheckBox("", null, true); public static final State NOT_SELECTED = new State(); public static final State SELECTED = new State(); public static final State DONT_CARE = new State(); public CheckTreeCellRenderer(MyRenderer delegate, CheckTreeSelectionModel selectionModel) { this.delegate = delegate; this.selectionModel = selectionModel; setLayout(new BorderLayout()); setOpaque(true); setBackground(new Color(207, 219, 234)); checkBox.setState(Boolean.TRUE); checkBox.setOpaque(true); checkBox.setBackground(new Color(207, 219, 234)); } public Component getTreeCellRendererComponent(JTree tree, Object value, boolean selected, boolean expanded, boolean leaf, int row, boolean hasFocus) { Component renderer = delegate.getTreeCellRendererComponent(tree, value, selected, expanded, leaf, row, hasFocus); TreePath path = tree.getPathForRow(row); if (path != null) { if (selectionModel.isPathSelected(path, true)) { checkBox.setState(Boolean.TRUE); } else { checkBox.setState(selectionModel.isPartiallySelected(path) ? null : Boolean.FALSE); } } renderer.setBackground(new Color(207, 219, 234)); tree.setOpaque(true); tree.setBackground(new Color(207, 219, 234)); this.setOpaque(true); this.setBackground(new Color(207, 219, 234)); add(checkBox, BorderLayout.WEST); add(renderer, BorderLayout.CENTER); return this; } }

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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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  • jms message not moving of the queue in websphere

    - by user271858
    I have a message driven bean that throws exception under certain conditions. When it throws an exception the message is not processed and put back on the queue. From what I understand with MQ and WAS (Websphere Application Server) the message should be marked as bad after x number of tries and removed from the queue. This is not happening and the message remains on the queue marked as bad. What part of the configuration in MQ and/or WAS have I missed to set correct? (The issue with the MDB throwing exceptions is NOT the point here) Thanks.

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  • how to trigger notification from other framework in atmosphere (comet)?

    - by Sean Xiong
    basically i have read some samples, but all are self contained in one servlet. such as: use doGet to establish the long polling connection, and then use doPost to trigger the event to notify all suspended connections. Here is my question: I have other web actions programming in spring mvc, in the spring mvc controller a user post a message via /message/post, how can I make this action to trigger the atmosphere handler to notify the suspended connections?

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  • Relative path in JLabel HTML

    - by kroiz
    Hi, I am trying to make JLabel show an html which is referencing an image using a relative path. But I cannot make JLabel locate the image. It works fine when I am using absolute path. I have tried running the program from the command line or from eclipse and add dialog to show me where is the current working directory but for avail. I have therefor came to the conclusion that the image is not searched in the current directory - which brings me to the point. where is the image looked for? here is a test code that show what I am doing: import javax.swing.*; public class HTMLLabel extends JFrame { public HTMLLabel() { setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); JOptionPane.showMessageDialog( this, System.getProperty("user.dir")); String html = "<html>\n" + " <body>\n" + " <div style=\"text-align: center;\">\n" + " <img src=\"file://s.png\">\n"+ " </div>\n"+ " </body>\n"+ "</html>"; JLabel label = new JLabel(html); add(label); pack(); setVisible(true); } public static void main(String[] args) { new HTMLLabel(); } }

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  • Why is BorderLayout calling setSize() and setBounds()?

    - by ags
    I'm trying to get my head around proper use of the different LayoutManagers to make my GUI design skills more efficient and effective. For me, that usually requires a detailed understanding of what is going on under the hood. I've found some good discussion of the interaction and consequences of a Container using BorderLayout containing a Container using FlowLayout. I understand it for the most part, but wanted to confirm my mental model and to do so I am looking at the code for BorderLayout. In the code snippet below taken from BorderLayout.layoutContainer(), note the calls to the child Component's setSize() method followed by setBounds(). Looking at the source for these methods of Component, setSize() actually calls setBounds() with the current values for Component.x and Component.y. Why is this done (and not entirely redudant?) Doesn't the setBounds() call completely overwrite the results of the setSize() call? if ((c=getChild(NORTH,ltr)) != null) { c.setSize(right - left, c.height); Dimension d = c.getPreferredSize(); c.setBounds(left, top, right - left, d.height); top += d.height + vgap; } I'm also tring to understand where/when the child Component's size is initially set (before the LayoutManager.layoutContainer() method is called). Finally, this post itself raises a "meta-question": in a situation like this, where the source is available elsewhere, is the accepteed protocol to include the entire method? Or some other way to make it easier for folks to participate in the thread? Thanks.

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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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  • 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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  • Tomcat Postgres Connection

    - by user191207
    Hi, I'm using a singleton class for a PostgresSQL connection inside a servelet. The problem is that once it is open it works for a while (I guess until some timeout), and then it starts throwing a I/O exception. Any idea what is happening to the singleton class inside Tomcat VM? Thanks

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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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  • Is there a version of postActionEvent for KeyEvent (specifically for a JTextArea)?

    - by Brian Pelc
    I'm writing a program that contains multiple JTextFields and 2 JTextAreas within an input panel. I have a submit button on the bottom. I have it set up so when a user types something into each field (including the JTextAreas) and hits the Enter key, it updates a text file, and when they press the submit button it updates the file then outputs a new version of it in the local directory. If the user presses Enter in any of the fields, it validates their input, however, I want to re-validate all fields when they press the submit button. Each field (again, JTextAreas included) has it's own validation check within its ActionListener or KeyListener (for the JTextAreas). It's easy enough to use postActionEvent() for the JTextFields, but is there a similar method for the JTextAreas to force fire a KeyEvent? I don't want to duplicate code and consume memory by re-writing the validation for those 2 Components inside the ActionEvent for the JButton. Unfortunately, I can't provide a sample because I'm writing the program on a classified machine (PC).

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  • Spring Integration 1.0 RC2: Streaming file content?

    - by gdm
    I've been trying to find information on this, but due to the immaturity of the Spring Integration framework I haven't had much luck. Here is my desired work flow: New files are placed in an 'Incoming' directory Files are picked up using a file:inbound-channel-adapter The file content is streamed, N lines at a time, to a 'Stage 1' channel, which parses the line into an intermediary (shared) representation. This parsed line is routed to multiple 'Stage 2' channels. Each 'Stage 2' channel does its own processing on the N available lines to convert them to a final representation. This channel must have a queue which ensures no Stage 2 channel is overwhelmed in the event that one channel processes significantly slower than the others. The final representation of the N lines is written to a file. There will be as many output files as there were routing destinations in step 4. *'N' above stands for any reasonable number of lines to read at a time, from [1, whatever I can fit into memory reasonably], but is guaranteed to always be less than the number of lines in the full file. How can I accomplish streaming (steps 3, 4, 5) in Spring Integration? It's fairly easy to do without streaming the files, but my files are large enough that I cannot read the entire file into memory. As a side note, I have a working implementation of this work flow without Spring Integration, but since we're using Spring Integration in other places in our project, I'd like to try it here to see how it performs and how the resulting code compares for length and clarity.

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  • Using ant, rename a directory without knowing the full path?

    - by mixonic
    Howdy friends, Given a zipfile with an unknown directory, how can I rename or move that directory to a normalized path? <!-- Going to fetch some stuff --> <target name="get.remote"> <!-- Get the zipfile --> <get src="http://myhost.com/package.zip" dest="package.zip"/> <!-- Unzip the file --> <unzip src="package.zip" dest="./"/> <!-- Now there is a package-3d28djh3 directory. The part after package- is a hash and cannot be known ahead of time --> <!-- Remove the zipfile --> <delete file="package.zip"/> <!-- Now we need to rename "package-3d28djh3" to "package". My best attempt is below, but it just moves package-3d28djh3 into package instead of renaming the directory. --> <!-- Make a new home for the contents. --> <mkdir dir="package" /> <!-- Move the contents --> <move todir="package/"> <fileset dir="."> <include name="package-*/*"/> </fileset> </move> </target> I'm not much of an ant user, any insight would be helpful. Thanks much, -Matt

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