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  • Passing dynamic string in hyperlink as parameter in jsp

    - by user3660263
    I am trying to pass a dynamic string builder variable in jsp I am generating a string through code. String Builder variable has some value but i am not able to pass it in at run time.It doesn't get the value. CODE FOR VARIABLE <% StringBuilder sb=new StringBuilder(""); if(request.getAttribute("Brand")!=null) { String Brand[]=(String[])request.getAttribute("Brand"); for(String brand:Brand) { sb.append("Brand="); sb.append(brand); sb.append("&&"); } } if(request.getAttribute("Flavour")!=null) { String Flavour[]=(String[])request.getAttribute("Flavour"); for(String flavour:Flavour) { sb.append(flavour); sb.append("&&"); } sb.trimToSize(); pageContext.setAttribute("sb", sb); } out.print("this is string"+sb); %> CODE FOR HYPERLINK <a href="Filter_Products?${sb}page=${currentPage + 1}" style="color: white;text-decoration: none;">Next</a></td>

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  • I need to do a BASICE For Loop algorithm for a java Pyramid

    - by user1665119
    Question 2. USE THE FOR LOOP. Design and write an algorithm that will read a single positive number from the keyboard and will then print a pyramid out on the screen. The pyramid will need to be of a height equal in lines to the number inputted by the operator. Your program is not to test for negative numbers, nor is it to cater for them. For your test, use the number 7. If you would like to take the problem further, try 18 and watch what happens. Example input: 4 Example output: 1 121 12321 1234321

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  • Java JPA @OneToMany neededs to reciprocate @ManyToOne?

    - by bguiz
    Create Table A ( ID varchar(8), Primary Key(ID) ); Create Table B ( ID varchar(8), A_ID varchar(8), Primary Key(ID), Foreign Key(A_ID) References A(ID) ); Given that I have created two tables using the SQL statements above, and I want to create Entity classes for them, for the class B, I have these member attributes: @Id @Column(name = "ID", nullable = false, length = 8) private String id; @JoinColumn(name = "A_ID", referencedColumnName = "ID", nullable = false) @ManyToOne(optional = false) private A AId; In class A, do I need to reciprocate the many-to-one relationship? @Id @Column(name = "ID", nullable = false, length = 8) private String id; @OneToMany(cascade = CascadeType.ALL, mappedBy = "AId") private List<B> BList; //<-- Is this attribute necessary? Is it a necessary or a good idea to have a reciprocal @OneToMany for the @ManyToOne? If I make the design decision to leave out the @OneToMany annotated attribute now, will come back to bite me further down.

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  • Where are the readonly/const in .NET?

    - by acidzombie24
    In C++ you'll see void func(const T& t) everywhere. However, i havent seen anything similar in .NET. Why? I have notice a nice amount of parameters using struct. But i see no functions with readonly/const. In fact now that i tried it i couldnt use those keywords to make a function that promises to not modify a list being passed in. Is there no way to promise the caller that this function will never modify the contents of list? Is there no way to say to call code and say this list should never be modified? (I know i can clone the list or look at documentation but i like compile errors sometime)

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  • Need help regarding lwuit

    - by rajiv
    Hi, I have project, already developed using canvas and lib used is LCDUI. It's for nokia keyboard supported devices. Now I want to incorporate same application for touch devices. I have used touch methods like pointerpressed, etc. For normal functionality that worked pretty well. But it creates problem in commands. My application is in fullscreen mode. Commands I have created using user defined menu list. Probles is that I can not directly identify that which command has been clicked. Setting coordinates for every command is not thr feasible solution for me. I come across the new lib LWUIT, but i found out that it supports only forms(Can't we use on canvas?). and integrating LCDUI and LWUIT is also not possible(please give suggestion that can we use both in same application?). Is it possible to create form under canvas itself? Any other lib support available? thank you.

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  • Multiple operations depending on the type of the object passed

    - by mixm
    Assuming I create a method which is passed an object and that method would perform an action depending on the object passed. How should I identify the object? I thought of using the class name to identify the object, but that may be impractical since I could easily change the class name of objects, and generate headaches during future development. Am I right? edit: for example, i have objects ball and bomb. if i have another object called wall, and the wall has the method to resolve collisions with the wall (e.g. the coordinates of the colliding ball and bomb) but have different logic depending on the colliding object (i.e. ball and bomb)

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  • How to signal object instantiation in a Collaboration/Communication Diagram?

    - by devoured elysium
    I'd like to know how to translate the following line of code to a Collaboration Diagram: Food food = new Food("abc", 123); I know that I can call an Food's method using the following notation: MyStaticMethod() ----------------------> -------- | | | Food | | | -------- being that equivalent to Taste taste = Food.MyStaticMethod(); and MyInstanceMethod() ----------------------> --------------- | | | food : Food | | | --------------- is equivalent to food.MyInstanceMethod(); but how do I signal that I want to call a given constructor on Food? Thanks

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  • How can a servlet always perform the same task?

    - by membersound
    I want a Servlet to perform always the same tasks. Regardless of if it is a GET or POST. At the moment I just call the doGet() from doPost(), which works fine. Then I tried overriding the service() method, and I thought it would just work the same way. But it does not! The code somehow gets executed, but the response does not generate the webpage: response.getWriter(); response.println(string); This code works for the doGet/doPost methods, but not for the service. Why? Servlet: class MyWebServlet extends HttpServlet { @Override public void service(ServletRequest request, ServletResponse response) { response.setContentType("text/html"); PrintWriter out = response.getWriter(); String string = "teststring"; out.println(string); } }

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  • How do I calculate a good hash code for a list of strings?

    - by Ian Ringrose
    Background: I have a short list of strings. The number of strings is not always the same, but are nearly always of the order of a “handful” In our database will store these strings in a 2nd normalised table These strings are never changed once they are written to the database. We wish to be able to match on these strings quickly in a query without the performance hit of doing lots of joins. So I am thinking of storing a hash code of all these strings in the main table and including it in our index, so the joins are only processed by the database when the hash code matches. So how do I get a good hashcode? I could: Xor the hash codes of all the string together Xor with multiply the result after each string (say by 31) Cat all the string together then get the hashcode Some other way So what do people think? (If you care we are using .NET and SqlServer)

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  • How do I correct feature envy in this case?

    - by RMorrisey
    I have some code that looks like: class Parent { private Intermediate intermediateContainer; public Intermediate getIntermediate(); } class Intermediate { private Child child; public Child getChild() {...} public void intermediateOp(); } class Child { public void something(); public void somethingElse(); } class Client { private Parent parent; public void something() { parent.getIntermediate().getChild().something(); } public void somethingElse() { parent.getIntermediate().getChild().somethingElse(); } public void intermediate() { parent.getIntermediate().intermediateOp(); } } I understand that is an example of the "feature envy" code smell. The question is, what's the best way to fix it? My first instinct is to put the three methods on parent: parent.something(); parent.somethingElse(); parent.intermediateOp(); ...but I feel like this duplicates code, and clutters the API of the Parent class (which is already rather busy). Do I want to store the result of getIntermediate(), and/or getChild(), and keep my own references to these objects?

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  • Designing a chain of states

    - by devoured elysium
    I want to model a kind of FSM(Finite State Machine). I have a sequence of states (let's say, from StateA to StateZ). This sequence is called a Chain and is implemented internally as a List. I will add states by the order I want them to run. My purpose is to be able to make a sequence of actions in my computer (for example, mouse clicks). (I know this has been done a zillion times). So a state is defined as a: boolean Precondition() <- Checks to see if for this state, some condition is true. For example, if I want to click in the Record button of a program, in this method I would check if the program's process is running or not. If it is, go to the next state in the chain list, otherwise, go to what was defined as the fail state (generally is the first state of them all). IState GetNextState() <- Returns the next state to evaluate. If Precondition() was sucessful, it should yield the next state in the chain otherwise it should yield the fail state. Run() Simply checks the Precondition() and sets the internal data so GetNextState() works as expected. So, a naive approach to this would be something like this: Chain chain = new Chain(); //chain.AddState(new State(Precondition, FailState, NextState) <- Method structure chain.AddState(new State(new WinampIsOpenCondition(), null, new <problem here, I want to referr to a state that still wasn't defined!>); The big problem is that I want to make a reference to a State that at this point still wasn't defined. I could circumvent the problem by using strings when refrering to states and using an internal hashtable, but isn't there a clearer alternative? I could just pass only the pre-condition and failure states in the constructor, having the chain just before execution put in each state the correct next state in a public property but that seems kind of awkward.

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  • Correct handling of return data

    - by Serhiy
    Hello, I have a question related to correct handling of returns of the DAO library I'm writing for one project. This library probably is going to be used by another people and I want to do it correctly. So I would like to know, how I should deal with return statements of the functions of my DAO. Example 1 I have function to getCustomer which should return String. In case query doesn't return any result should I return null, empty string or throw some kind of Exception? Example 2 I have function getCutomerList which return ArrayList. In case query doesn't return any result should I return null, empty ArrayList or throw some Exception? Example 3 Some sql exception was detected, what should I do: throw exception or do try..catch of the block where it can occur? What is the "good" practice or "best" practice to apply in my case? Thanks on advance, Serhiy.

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  • How to use sound and images in a Java applet?

    - by Click Upvote
    Question 1: How should I structure my project so the sound and images files can be loaded most easily? Right now, I have the folder: C:\java\pacman with the sub-directory C:\java\pacman\src containing all the code, and C:\java\pacman\assets containing the images and .wav files. Is this the best structure or should I put the assets somewhere else? Question 2: What's the best way to refer to the images/sounds without using the full path e.g C:\java\pacman\assets\something.png to them? If I use the getCodeBase() function it seems to refer to the C:\java\pacman\bin instead of C:\java\pacman\. I want to use such a function/class which would work automatically when i compile the applet in a jar as well as right now when I test the applet through eclipse. Question 3: How should I load the images/sounds? This is what I'm using now: 1) For general images: import java.awt.Image; public Image getImg(String file) { //imgDir in this case is a hardcoded string containing //"C:\\java\\pacman\\assets\\" file=imgDir + file; return new ImageIcon(file).getImage(); } The images returned from this function are used in the drawImage method of the Graphics class in the paint method of the applet. 2) For a buffered image, which is used to get subImages and load sprites from a sprite sheet: public BufferedImage getSheet() throws IOException { return ImageIO.read(new File(img.getPath("pacman-sprites.png"))); } Later: public void loadSprites() { BufferedImage sheet; try { sheet=getSheet(); redGhost.setNormalImg(sheet.getSubimage(0, 60, 20, 20)); redGhost.setUpImg(sheet.getSubimage(0, 60, 20, 20)); redGhost.setDownImg(sheet.getSubimage(30, 60, 20, 20)); redGhost.setLeftImg(sheet.getSubimage(30, 60, 20, 20)); redGhost.setRightImg(sheet.getSubimage(60, 60, 20, 20)); } catch (IOException e) { System.out.println("Couldnt open file!"); System.out.println(e.getLocalizedMessage()); } } 3) For sound files: import sun.audio.*; import java.io.*; public synchronized void play() { try { InputStream in = new FileInputStream(filename); AudioStream as = new AudioStream(in); AudioPlayer.player.start(as); } catch (IOException e) { e.printStackTrace(); } }

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  • postgresql duplicate table names best practice

    - by veilig
    My company has a handful of apps that we deploy in the websites we build. Recently a very old app needed to be included along side a newer app and there was a conflict w/ a duplicate table name needed to be used by both apps. We are now in the process of updating an old app and there will be some DB updates. I'm curious what people consider best practice (or how do you do it) to help ensure these name collisions don't happen. I've looked at schema's but not sure if thats the right path we want to take. As the documentation prescribes, I don't want to "wire" a particular schema name into an application and if I add schema's to the user search path how would it know which table I was referring to if two schema's have the same table name. although, maybe I'm reading to much into this. Any insights or words of wisdom would be greatly appreciated!

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  • JSR-299 (CDI) configuration at runtime

    - by nsn
    I need to configure different @Alternatives, @Decorators and @Injectors for different runtime environments (think testing, staging and production servers). Right now I use maven to create three wars, and the only difference between those wars are in the beans.xml files. Is there a better way to do this? I do have @Alternative @Stereotypes for the different environments, but even then I need to alter beans.xml, and they don't work for @Decorators (or do they?) Is it somehow possible to instruct CDI to ignore the values in beans.xml and use a custom configuration source? Because then I could for example read a system property or other environment variable. The application exclusively runs in containers that use Weld, so a weld-specific solution would be ok. I already tried to google this but can't seem to find good search terms, and I asked the Weld-Users-Forums, but to no avail. Someone over there suggested to write my own custom extension, but I can't find any API to actually change the container configuration at runtime. I think it would be possible to have some sort of @ApplicationScoped configuration bean and inject that into all @Decorators which could then decide themselves whether they should be active or not and then in order to configure @Alternatives write @Produces methods for every interface with multiple implementations and inject the config bean there too. But this seems to me like a lot of unnecessary work to essentially duplicate functionality already present in CDI?

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  • how to force ejb3 to reload value from data base and not use those of the context

    - by Kohan95
    Hello here I have a big problem that I hope to find help here I have two entities @Entity @Inheritance(strategy=InheritanceType.JOINED) @DiscriminatorColumn(name="Role", discriminatorType=DiscriminatorType.STRING) public class Utilisateur implements Serializable { private static final long serialVersionUID = 1L; @Id @GeneratedValue(strategy = GenerationType.IDENTITY) @Column(name="id") private Long id; @Column(name="nom",nullable=false) private String nom; @Column(name="Role",nullable=false, insertable=false) private String Role ; //... } @Entity @Table(name="ResCom") @DiscriminatorValue("ResCom") public class ResCom extends Utilisateur { /... } the first thing I do ResCom rsCom= new ResCom(nom,prenom, email,civilite, SysQl.crypePasse(pass)); gr.create(rsCom); I check my database I see that property is ResCom insert but when I check the value of role I get null Utilisateur tets= gr.findByEmail(email); message=tets.getEmail()+" and Role :"+tets.getRole()+""; but in my bass it ResCom !!!!! the problem disappears when I deploy the project again I hope you have a solution And thank you in advance sorry for my English

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  • Problem updating collection using JPA

    - by FarmBoy
    I have an entity class Foo foo that contains Collection<Bar> bars. I've tried a variety of ways, but I'm unable to successfully update my collection. One attempt: foo = em.find(key); foo.getBars().clear(); foo.setBars(bars); em.flush; \\ commit, etc. This appends the new collection to the old one. Another attempt: foo = em.find(key); bars = foo.getBars(); for (Bar bar : bars) { em.remove(bar); } em.flush; At this point, I thought I could add the new collection, but I find that the entity foo has been wiped out. Here are some annotations. In Foo: @OneToMany(cascade = { CascadeType.ALL }, mappedBy = "foo") private List<Bar> bars; In Bar: @ManyToOne(optional = false, cascade = { CascadeType.ALL }) @JoinColumn(name = "FOO_ID") private Foo foo; Has anyone else had trouble with this? Any ideas?

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  • J2EE and alternatives

    - by Ilya K
    Hello, I am J2SE developer but I have rich web-background (php, perl/cgi and so on) and now I am starting new project. It will have web interface, spaghetti business logic, relational database as storage and connections to other services. I do it from the scratch. My colleagues told me to use spring, spring security and struts. I look briefly at J2EE spec and found that it covers almost all aspects of enterprise application. I asked my colleagues why do they need spring and struts, but looks like they use technologies simply because they are familiar with them and not familiar with classic J2EE stack. So, my question is: what is bad about J2EE? Why do I need spring if there are JNDI lookups? It will take a day or two to create fake InitialContext for unit-tests. And that is all: I stand with out of external tools like spring. Why do I need spring-security if there is a security built in Servlets spec? I can map any request to any servlet using web.xml, no struts.xml is needed. I can use servlet-filters instead of struts interceptors. There is RMI, so I do not need spring-remote. And so on.. Why should I bother my self with all that fancy stuff if there is J2EE? I really want to find situation when J2EE is not enough. Do you have any? Thanks!

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  • JBoss 4.2.3 - how to find path to jar file

    - by Gribbler
    I'm getting an error in a JBOSS application: Static Method [addHeader] not found on JavaBean [class com.ppnet.webservice.WebserviceHeaderWriter] I have checked the WebserviceHeaderWriter.jar that gets deployed into JBOSS and checked it in eclipse. It looks as if it should have this method on it. I think that the JBoss application might be loading a different version of the WebserviceHeaderWriter.jar without this method on it, is there a way to check the location of the file that is getting loaded?

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  • When should I use a struct instead of a class?

    - by Esteban Araya
    MSDN says that you should use structs when you need lightweight objects. Are there any other scenarios when a struct is preferable over a class? Edit: Some people have forgotten that: 1. structs can have methods! 2. structs have no inheritance capabilites. Another Edit: I understand the technical differences, I just don't have a good feel for WHEN to use a struct.

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  • Inheritence and usage of dynamic_cast

    - by Mewzer
    Hello, Suppose I have 3 classes as follows (as this is an example, it will not compile!): class Base { public: Base(){} virtual ~Base(){} virtual void DoSomething() = 0; virtual void DoSomethingElse() = 0; }; class Derived1 { public: Derived1(){} virtual ~Derived1(){} virtual void DoSomething(){ ... } virtual void DoSomethingElse(){ ... } virtual void SpecialD1DoSomething{ ... } }; class Derived2 { public: Derived2(){} virtual ~Derived2(){} virtual void DoSomething(){ ... } virtual void DoSomethingElse(){ ... } virtual void SpecialD2DoSomething{ ... } }; I want to create an instance of Derived1 or Derived2 depending on some setting that is not available until run-time. As I cannot determine the derived type until run-time, then do you think the following is bad practice?... class X { public: .... void GetConfigurationValue() { .... // Get configuration setting, I need a "Derived1" b = new Derived1(); // Now I want to call the special DoSomething for Derived1 (dynamic_cast<Derived1*>(b))->SpecialD1DoSomething(); } private: Base* b; }; I have generally read that usage of dynamic_cast is bad, but as I said, I don't know which type to create until run-time. Please help!

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  • Java: Convenient way to refactor the application.

    - by Harshal
    Hi, Everyone We have an agile enterprise application built on JSP and Servlet without any design strategy. This application was built in early 2002 considering 1000 users. After 2002, we received lots of requests from the marketing partners. Currently, the application has lots of spaghetti code with lots of Ifs and elses. One class has more than 20,000 lines of code with a huge body of functions without abstraction. Now, we need to support billions of records, what we need to do immediately and gradually? We have to refactor the application? Which framework, we need to use? How the usage of the framework will be helpful to the end users? How to convince the leaders to do the refactoring? How to gain the faster response time as compare to the current system?

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  • How to convert map to url query string?

    - by Ula Krukar
    Do you know of any utility class/library, that can convert Map into URL-friendly query string? Example: I have a map: - "param1"=12, - "param2"="cat" I want to get: param1=12&param2=cat. PS. I know I can easily write it myself, I am just surprised that I cannot find it anywhere (I checked Apache Commons so far).

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