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  • Loading data from file to Vector structure

    - by owca
    I'm trying to parse through fixed-width formatted file extracting x,y values of points from it, and then storing them in int[] array inside a Vector. Text file looks as follows : 0006 0015 0125 0047 0250 0131 That's the code : Vector<int[]> vc = new Vector<int[]>(); try { BufferedReader file = new BufferedReader(new FileReader("myfile.txt")); String s; int[] vec = new int[2]; while ((s = file.readLine()) != null) { vec[0] = Integer.parseInt(s.substring(0, 4).trim()); vec[1] = Integer.parseInt(s.substring(5, 8).trim()); vc.add(vec); } file.close(); } catch (IOException e) { } for(int i=0; i<vc.size(); i++){ for(int j=0; j<2; j++){ System.out.println(vc.elementAt(i)[j]); } } But the output shows only last line. 250 131 250 131 250 131 Should I somehow use Vector.nextElement() here to get all my data ?

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  • Benefits of arrays

    - by Vitalii Fedorenko
    As I see it, the advantages of List over array are pretty obvious: Generics provide more precise typing: List<Integer>, List<? extends Number>, List<? super Integer>. List interface has a bunch useful methods: addAll, remove etc. While for arrays all standard operations except get/set must be performed in a procedure manner by passing it to a static method. Collections offer different implementations like ArrayList, LinkedList, unmodifieable and synchronized lists, which can be hidden under common List interface. OOB length control. As disadvantages I can only mention absence of syntactic sugar and runtime type check. At the same time supporting of both structures requires frequent using of asList and toArray methods, which makes code less readable. So I am curious if there are any important benefits of using arrays that I miss.

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  • Have something loaded only when JList item is visibile

    - by elvencode
    Hello, i'm implementing a Jlist populated with a lot of elements. Each element corresponds to a image so i'd like to show a resized preview of them inside each row of the list. I've implemented a custom ImageCellRenderer extending the Jlabel and on getListCellRendererComponent i create the thumbnail if there'snt any for that element. Each row corresponds to a Page class where i store the path of the image and the icon applied to the JLabel. Each Page object is put inside a DefaultListModel to populate the JList. The render code is something like this: public Component getListCellRendererComponent( JList list, Object value, int index, boolean isSelected, boolean cellHasFocus) { Page page = (Page) value; if (page.getImgIcon() == null) { System.out.println(String.format("Creating thumbnail of %s", page.getImgFilename())); ImageIcon icon = new ImageIcon(page.getImgFilename()); int thumb_width = icon.getIconWidth() > icon.getIconHeight() ? 128 : ((icon.getIconWidth() * 128) / icon.getIconHeight()); int thumb_height = icon.getIconHeight() > icon.getIconWidth() ? 128 : ((icon.getIconHeight() * 128) / icon.getIconWidth()); icon.setImage(getScaledImage(icon.getImage(), thumb_width, thumb_height)); page.setImgIcon(icon); } setIcon(page.getImgIcon()); } I was thinking that only a certain item is visibile in the List the cell renderer is called but i'm seeing that all the thumnails are created when i add the Page object to the list model. I've tried to load the items and after set the model in the JList or set the model first and after starting appending the items but the results are the same. Is there any way to load the data only when necessary or do i need to create a custom control like a JScrollPanel with stacked items inside where i check myself the visibility of each elements? Thanks

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  • Whats wrong with this method?

    - by David
    Here's the method: public static String CPUcolor () { System.out.println ("What color am I?") ; String s = getIns() ; System.out.println ("are you sure I'm "+s+"? (Y/N)") ; String a = getIns() ; while (!((a.equals ("y")) || (a.equals ("Y")) || (a.equals ("n")) || (a.equals ("N")))) { System.out.println ("try again") ; a = getIns () ; } if (a.equals ("n") || a.equals("N")) {CPUcolor() ;} System.out.println ("I am "+s) ; return s ; } here is a possible output of this method (y's and n's are user inputs): What color am I? red are you sure I'm red? (Y/N) N What color am I? blue are you sure I'm blue? (Y/N) N What color am I? Yellow are you sure I'm Yellow? (Y/N) y I am Yellow I am blue I am red Why is it that the line's "I am blue" and "I am Blue" printed? Why are they printed in reverse order with red, the first entered, printed last?

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  • Which faces technology for use with GlassFish 2.1 and NetBeans 6.7?

    - by SteJav
    I'm running GlassFish 2.1 and using NetBeans 6.7. I'd like to create a web interface to my data using JSF 1.2. Trouble is, I'm not sure which 'faces' technology to learn (that includes some good documentation). JBoss/RichFaces seem pretty good on documentation, but I'm using GlassFish. Any thoughts? The choices appear overwhelming: Tomahawk Tobago Trinidad ICEfaces RCFaces Netadvantage WebGalileoFaces QuipuKit BluePrints Woodstock JBoss RichFaces Ajax4jsf ILOG Oracle ADF G4JSF Simplica Backbase jenia4faces VisualWebPack DynaFaces IBM Impl Dinamica Mojarra PrimeFaces jQuery OpenFaces ZK ExtJS Anybody had any experience with any of the above and found the documentation to be clear to a beginner? Being a JSF/Web beginner, I tried some ICEFaces, Mojarra tutorials and had a go at getting RichFaces working with NBeans and GlassFish, but no luck. Lots of XML complaints. I'm clearly missing some huge chunks of configuration, but I can't find any documentation to help me. Any suggestions would be much appreciated :-)

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  • Can fields of the class and arguments of the method interfere?

    - by Roman
    I have a class with a fields called "a". In the class I have a method and in the list of arguments of this method I also have "a". So, which "a" I will see inside of the method? Will it be the field or it will be the argument of the method? public class myClass { private String a; // Method which sets the value of the field "a". public void setA(String a) { a = a; } } By the way, there is a similar situation. A method has some local (for method) variables whose names coincide with the names of the fields. What will the "see" the method if I refer to such a method-local variable inside the method (the field or the local variable)?

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  • Generate URL for File

    - by Don
    The default output of File.toURL() is file:/c:/foo/bar These don't appear to work on windows, and need to be changed to file:///c:/foo/bar Does the format file:/c:/foo/bar work correctly on Unix (I don't have a Unix machine to test on)? Is there a library that can take care of generating a URL from a File that is in the correct format for the current environment?

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  • ActiveMq integration with Spring 2.5

    - by Tony
    I am using ActiveMq 5.32 with Spring 2.5.5. I use pretty generic configuration, as long as I include the jmsTransactionManager in DefaultMessageListenerContainer, Spring throw an error on start up: "Error creating bean with name 'org.springframework.jms.listener.DefaultMessageListenerContainer#0'" Without the transactionManager attribute , this works fine, but when I add 10 messages to the message queue, a transaction exception will occur. Part of my configurations : <bean class="org.springframework.jms.listener.DefaultMessageListenerContainer"> <property name="connectionFactory" ref="connectionFactory" /> <property name="destination" ref="emailDestination" /> <property name="messageListener" ref="emailServiceMDP" /> <property name="transactionManager" ref="jmsTransactionManager" /> </bean> <bean id="jmsTransactionManager" class="org.springframework.jms.connection.JmsTransactionManager"> <property name="connectionFactory" ref="connectionFactory" /> </bean> Does this version of Spring and Activemq has some know issues in integration ? Or do I need additional libs to get jmsTransactionManager to work ?

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  • Generating different randoms valid for a day on different independent devices?

    - by Pentium10
    Let me describe the system. There are several mobile devices, each independent from each other, and they are generating content for the same record id. I want to avoid generating the same content for the same record on different devices, for this I though I would use a random and make it so too cluster the content pool based on these randoms. Suppose you have choices from 1 to 100. Day 1 Device#1 will choose for the record#33 between 1-10 Device#2 will choose for the record#33 between 40-50 Device#3 will choose for the record#33 between 50-60 Device#1 will choose for the record#55 between 40-50 Device#2 will choose for the record#55 between 1-10 Device#3 will choose for the record#55 between 10-20 Device#1 will choose for the record#11 between 1-10 Device#2 will choose for the record#22 between 1-10 Device#3 will choose for the record#99 between 1-10 Day 2 Device#1 will choose for the record#33 between 90-100 Device#2 will choose for the record#33 between 1-10 Device#3 will choose for the record#33 between 50-60 They don't have access to a central server. Data available for each of them: IMEI (unique per mobile) Date of today (same on all devices) Record id (same on all devices) What do you think, how is it possible? ps. tags can be edited

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  • Is there any point in using a volatile long?

    - by Adamski
    I occasionally use a volatile instance variable in cases where I have two threads reading from / writing to it and don't want the overhead (or potential deadlock risk) of taking out a lock; for example a timer thread periodically updating an int ID that is exposed as a getter on some class: public class MyClass { private volatile int id; public MyClass() { ScheduledExecutorService execService = Executors.newScheduledThreadPool(1); execService.scheduleAtFixedRate(new Runnable() { public void run() { ++id; } }, 0L, 30L, TimeUnit.SECONDS); } public int getId() { return id; } } My question: Given that the JLS only guarantees that 32-bit reads will be atomic is there any point in ever using a volatile long? (i.e. 64-bit). Caveat: Please do not reply saying that using volatile over synchronized is a case of pre-optimisation; I am well aware of how / when to use synchronized but there are cases where volatile is preferable. For example, when defining a Spring bean for use in a single-threaded application I tend to favour volatile instance variables, as there is no guarantee that the Spring context will initialise each bean's properties in the main thread.

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  • Help need for openfast implementation

    - by ganuke
    Our stock exchange going to implement FAST messaging in their system in order to reduced the bandwidth usage. We have already implement the FIX based application to trade with Stock exchange. In future we need implement FIX FAST in our application to communicate with them. I found that OPEN FAST is FAST based library. But I do not have any idea how to start with it. I went through OpenFast web site but could not find much support on how to use templates and dictionaries. Can some one guide me or provide some resources to start with? Thanks in advance.

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  • problem in extending a class

    - by Vineeth
    there are two classes public class Account { public Acconut() { //constructor } } public class SavingsAccount extends Account { } while doing the inheritance i have got an error message "cannont find symbol Symbol: constructor Account()" what might be the error in my code...??

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  • A member variable's hashCode() value is different

    - by Jacques René Mesrine
    There's a piece of code that looks like this. The problem is that during bootup, 2 initialization takes place. (1) Some method does a reflection on ForumRepository & performs a newInstance() purely to invoke #setCacheEngine. (2) Another method following that invokes #start(). I am noticing that the hashCode of the #cache member variable is different sometimes in some weird scenarios. Since only 1 piece of code invokes #setCacheEngine, how can the hashCode change during runtime (I am assuming that a different instance will have a different hashCode). Is there a bug here somewhere ? public class ForumRepository implements Cacheable { private static CacheEngine cache; private static ForumRepository instance; public void setCacheEngine(CacheEngine engine) { cache = engine; } public synchronized static void start() { instance = new ForumRepository(); } public synchronized static void addForum( ... ) { cache.add( .. ); System.out.println( cache.hashCode() ); // snipped } public synchronized static void getForum( ... ) { ... cache.get( .. ); System.out.println( cache.hashCode() ); // snipped } }

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  • Why I cannot see an image if I do not use the full name of an image?

    - by Roman
    I try to add an image to JPanel. It works if I specify the full name of the image (including name of all folders). But I want my software to be machine independent (another machine does not have the same folder structure as my machine has). So, I put my image to the same place where the source is and in my code I use just name of the image (no folders' names). It does not work. I put my image into the folder where my executables are. It does not work again. So, why it does not work and what can I do with that?

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  • can't understand the url function used in the google taskque api documentation

    - by Bunny Rabbit
    import com.google.appengine.api.labs.taskqueue.Queue; import com.google.appengine.api.labs.taskqueue.QueueFactory; import static com.google.appengine.api.labs.taskqueue.TaskOptions.Builder.*; // ... Queue queue = QueueFactory.getDefaultQueue(); queue.add(url("/worker").param("key", key)) in the code example given on the google task queue documentation page i can't understand the url("/worker") function they are calling in the queues.add() invocation .

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  • Mapping enum to a table with hibernate annotation

    - by Thierry-Dimitri Roy
    I have a table DEAL and a table DEAL_TYPE. I would like to map this code: public class Deal { DealType type; } public enum DealType { BASE("Base"), EXTRA("Extra"); } The problem is that the data already exist in the database. And I'm having a hard time mapping the classes to the database. The database looks something like that: TABLE DEAL { Long id; Long typeId; } TABLE DEAL_TYPE { Long id; String text; } I know I could use a simple @OneToMany relationship from deal to deal type, but I would prefer to use an enum. Is this possible? I almost got it working by using a EnumType.ORDINAL type. But unfortunately, my IDs in my deal type table are not sequential, and do not start at 1. Any suggestions?

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  • What do the external JSF libraries/frameworks add?

    - by kgrad
    I have seen mention of a bunch of external JSF Libraries such as ICEfaces, Richfaces, etc. However, I am unsure as to what these libraries actually add over just using JSF 2.0. Are they just additional components that are pre-built? I know that PrettyFaces adds URL rewriting, and I Believe that ICEFaces/Richfaces add Ajax enabled components? What are some other major component libraries, what are their benefits / why should people use them? Additionally, what does a framework like SEAM add over using straight JSF2 with EJB? Is MYFaces simply a different implementation of JSF?

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  • How to trigger code on two different servers in a WAS cluster?

    - by Dean J
    I have an administrative page in a web application that resets the cache, but it only resets the cache on the current JVM. The web application is deployed as a cluster to two WAS servers. Any way that I can elegantly have the "clear cache" button on each server trigger the method on both JVMs? Edit: The original developer just wrote a singleton holding a HashMap to be the cache in question. Lightweight and (previously) worked just fine for the requirements. It caches content pulled from six or seven web services for specified amounts of time. Edit: The entire application in question is three pages, so the elegant solution might well be the lightest solution.

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  • Create a new log file every time my program is run

    - by Bernhard V
    Hi, I am using the Apache commons logging library and log4j to generate my log files. Now I want to create a new file every time I run my program. The current count should be appended to the log file's name. For example: program_1.log program_2.log program_3.log Do you know how I could achieve this?

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