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  • How to recursively serialize an object using reflection ?

    - by Tony
    I want to navigate to the N-th level of an object, and serialize it's properties in String format. For Example: class Animal { public String name; public int weight; public Animal friend; public Set<Animal> children = new HashSet<Animal>() ; } should be serialized like this: {name:"Monkey", weight:200, friend:{name:"Monkey Friend",weight:300 ,children:{...if has children}}, children:{name:"MonkeyChild1",weight:100,children:{... recursively nested}} } And you may probably notice that it is similar to serializing an object to json. I know there're many libs can do this, can you give me some instructive ideas on how to write this?

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  • Spring JPA and persistence.xml

    - by bmw0128
    I'm trying to set up a Spring JPA Hibernate simple example WAR for deployment to Glassfish. I see some examples use a persistence.xml file, and other examples do not. Some examples use a dataSource, and some do not. So far my understanding is that a dataSource is not needed if I have: <persistence-unit name="educationPU" transaction-type="JTA"> <provider>org.hibernate.ejb.HibernatePersistence</provider> <class>com.coe.jpa.StudentProfile</class> <properties> <property name="hibernate.connection.driver_class" value="com.mysql.jdbc.Driver" /> <property name="hibernate.connection.url" value="jdbc:mysql://localhost:3306/COE" /> <property name="hibernate.connection.username" value="root" /> <property name="show_sql" value="true" /> <property name="dialect" value="org.hibernate.dialect.MySQLDialect" /> </properties> </persistence-unit> I can deploy fine, but my EntityManager is not getting injected by Spring. My applicationContext.xml: <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalEntityManagerFactoryBean"> <property name="persistenceUnitName" value="educationPU" /> </bean> <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager"> <property name="entityManagerFactory" ref="entityManagerFactory" /> </bean> <bean class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor" /> <tx:annotation-driven transaction-manager="transactionManager" /> <bean id="StudentProfileDAO" class="com.coe.jpa.StudentProfileDAO"> <property name="entityManagerFactory" ref="entityManagerFactory" /> </bean> <bean id="studentService" class="com.coe.services.StudentService"> </bean> My class with the EntityManager: public class StudentService { private String saveMessage; private String showModal; private String modalHeader; private StudentProfile studentProfile; private String lastName; private String firstName; @PersistenceContext(unitName="educationPU") private EntityManager em; @Transactional public String save() { System.out.println("*** em: " + this.em); //em is null this.studentProfile= new StudentProfile(); this.saveMessage = "saved"; this.showModal = "true"; this.modalHeader= "Information Saved"; return "successs"; } My web.xml: <listener> <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class> Are there any pieces I am missing to have Spring inject "em" in to StudentService?

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  • Mergesort : Revision

    - by stan
    Does merge sort work by; taking a list of values splitting it in to two take the first element of each list, the lowest value one goes in to a new list(and i guess removed from the original). comare the next two numbers - do this until one list is empty, then place the rest of the other list at the end ofthe nw list? Also, what are the ramifications of doing this on a linked list? Thanks

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  • Counting the number of objects that meets a certain criteria

    - by Candy Chiu
    The title doesn't tell the complete story. Please read the message. I have two objects: Adult and Child. Child has a boolean field isMale, and a reference to Adult. Adult doesn't reference Child. public class Adult { long id; } public class Child { long id; boolean isMale; Adult parent; } I want to create a query to list the number of sons each adult has including adults who don't have any sons. I tried: Query 1 SELECT adult, COUNT(child) FROM Child child RIGHT OUTER JOIN child.parent as adult WHERE child.isMale='true' GROUP BY adult which translates to sql select adult.id as col_0_0_, count(child.id) as col_1_0_, ... {omit properties} from Child child right outer join Adult adult on child.parentId=adult.id where child.isMale = 'true' group by adult.id Query 1 doesn't pick up adults that don't have any sons. Query 2: SELECT adult, COUNT(child.isMale) FROM Child child RIGHT OUTER JOIN child.parent as adult GROUP BY adult translates to sql: select adult.id as col_0_0_, count(child.id) as col_1_0_, ... {omit properties} from Child child right outer join Adult adult on child.parentId=adult.id group by adult.id Query 2 doesn't have the right count of sons. Basically COUNT doesn't evaluate isMale. The where clause in Query 1 filtered out Adults with no sons. How do I build a HQL or a Criteria query for this use case? Thanks.

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  • Ensure a new session every time the user connects to a Servlet

    - by Daziplqa
    Hi, I've a JSP/Servlet Web App that consist of more than one servlet (and some JSPs) I need to create an new HttpSession whenever the users access servlet A, knowing that, servlet A is the home page (i.e. he access it as the first servlet/page in the application) so far so good, I can write the following code at the start of the servlet A: HttpSession session = request.getSession(false); if (session == null) { logger.debug("starting new session..."); session = request.getSession(); // other staff here } But the problem is, if the user didn't close his browser (even if he closes the tab - in firefox for instance - the session will still be open), so when he try to open my site again, the last session will be re-used (in the rage of session timeout ofcourse), and this I don't need. I need whenever he access Servlet A, he got created a brand new HttpSession. but unfortunately, he may access this servlet twice per session based on some scenario!! Please help.

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  • Strage character encoding problem with Eclipse / Spring / Tomcat 6

    - by Czar
    Hi, I have been trying things all da but can't get a proper solution. My problem is: I am developing a Spring MVC based app in my local Tomcat. My MYSQl database has UTF-8 encoding set, all content in there displays properly when using phpMyAdmin. Also the output in LOG files using log4j in catalina.out works fine. My JSP pages are configured by <!-- encoding --> <%@ page contentType="text/html; charset=UTF-8" %> <%@ page pageEncoding="UTF-8" %> Also showing data on my JSP works fine. I can also send data from my Controller without any DB intereference using special chars, e.g. String str = "UTF-8 Test: Ä Ö Ü ß è é â"; logger.debug(str); mav.addObject("utftest", str); That displays correctly in log and on jsp page in browser. BUT: When having special chars directly in my JSP file, e.g. for text in headers, this does not work. FF and Google Chrome display strange chars but report the page to be UTF-8. When switching to Latin, the chars just get more and more strange. Same problem when showing text tokens from my messages.properties file, although Eclipse says when right-clicking that UTF-8 will be used. I am a little it lost and don't know where to check now. Summary: DB storage is fine DB output on JSP is fine Output on JSP directly form controller is fine even reading in form forms is fine .properties files and JSP text is not fine !!! Any ideas? I really appreciate and tips.

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  • Spring 2.5 Hibernate 3.5 NamedQuery

    - by EugeneP
    I do not use HibernateTemplate, but work with getCurrentSession() in my DAO. I would like to know how to declare Hibernate named queries in a beans.xml file (I do not use hbm.xml). And maybe Spring has alternative means to declare Hibernate named queries?

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  • Is regex too slow? Real life examples where simple non-regex alternative is better

    - by polygenelubricants
    I've seen people here made comments like "regex is too slow!", or "why would you do something so simple using regex!" (and then present a 10+ lines alternative instead), etc. I haven't really used regex in industrial setting, so I'm curious if there are applications where regex is demonstratably just too slow, AND where a simple non-regex alternative exists that performs significantly (maybe even asymptotically!) better. Obviously many highly-specialized string manipulations with sophisticated string algorithms will outperform regex easily, but I'm talking about cases where a simple solution exists and significantly outperforms regex. What counts as simple is subjective, of course, but I think a reasonable standard is that if it uses only String, StringBuilder, etc, then it's probably simple.

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  • jaxb unmarshaling with schema validation in runtime

    - by ekeren
    I am using jaxb for my application configurations I feel like I am doing something really crooked and I am looking for a way to not need an actual file or this transaction. As you can see in code I: 1.create a schema into a file from my JaxbContext (from my class annotation actually) 2.set this schema file in order to allow true validation when I unmarshal Schema mySchema = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI).newSchema(schemaFile); jaxbContext.generateSchema(new MySchemaOutputResolver()); // ultimately creates schemaFile Unmarshaller u = m_context.createUnmarshaller(); u.setSchema(mySchema); u.unmarshal(...); do any of you know how I can validate jaxb without needing to create a schema file that sits in my computer? Do I need to create a schema for validation, it looks redundant when I get it by JaxbContect.generateSchema ? How do you do this?

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  • how do I know when/where to invoke the overridden method of the super class

    - by Henry
    Hi, This question occured to me while programming a Android application, but it seems to be a general programming question more. The situation is, I am extending (subclass-ing) an class from a library, and overriding a method. how do I know if I should invoke the method of super-class? and when? (in the beginning of the overridden method or in the end?) For example, I am overriding the method "public boolean onCreateOptionsMenu(Menu menu)" from class "Activity" in Android platform. And I saw someone write "return super.onCreateOptionsMenu(menu)" in the end of the method, in an example. But how do I know it should be done this way? and it is correct or not? what's the difference if I begin my method with "super.onCreateOptionsMenu(menu)"? BR, Henry

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  • Eclipse WTP, Axis 2 Web Service Client

    - by asrijaal
    Hi, I'm trying to build a web service and a client for this service. I'm using Eclipse 3.5.1 with axis2-1.4.1. I'm facing a problem: I created the web service via the web service wizard and the service shows up in the axis service list. If I porint to the wsdl - its generated. Now when I'm trying to build the client, I choose the wsdl, the client project and take the next button, well at the client web service configuration everything is empty. There is nor service name, no port name. Am I facing a bug? Anyoneelse faced something like this? Regards

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  • Calling one DAO from another DAO?

    - by es11
    Can this ever make sense? Say I need to fetch an object from the DB which has a relation to another object (represented by a foreign key in the DB, and by a composition in my domain object). If in my first DAO I fetch the data for object 1, then call the dao for object 2, and finally (from within the first DAO, call the setter in object 1 and give it the previously fetched object 2). I know I could do a join instead, but it just seems more logical to me to decouple the functionality (which is why I am skeptical about calling one dao from another). Or should I move some of the logic to the service layer? Thanks Update: I think I solved the problem with help from the answers: all I needed to do was add the following to my mapping of Object 1: <one-to-one name="Object2" fetch="join" class="com...Object2"></one-to-one> I didn't have to change anything else. Thanks for the help!

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  • How do i create a group of h:selectOneRadio in JSF?

    - by Nitesh Panchal
    Hello, I am trying to create a grooup of h:selectOneRadio but ui:repeat gives it different id for each row. This is my code :- <ui:repeat id="themes" value="#{RegisterBean.objBlogTemplateList}" var="item"> <p:graphicImage alt="#{item.templatePicName}" style="border: solid 5px white;width: 200px;height: 200px;" value="#{app:getCommonImagePath(item.templatePicName)}"/> <h:selectOneRadio rendered="false" value="#{RegisterBean.blogTemplateId}" layout="lineDirection" id = "rdTemplateId"> <f:selectItem itemLabel="#{item.templateName}" itemValue="#{item.templateId}"/> </h:selectOneRadio> </ui:repeat> Actually i want to create a single radio button with different selectItems in it which should be from the rows of my table in database. How do i do this?

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  • Retrieve data from .dat file.

    - by Zach
    We have an application which requires us to read data from a file (.dat) dynamically using deserialization. We are actually getting first object and it throws null pointer exception when we are accessing other objects using a "for" loop. File file=null; FileOutputStream fos=null; BufferedOutputStream bos=null; ObjectOutputStream oos=null; try{ file=new File("account4.dat"); fos=new FileOutputStream(file,true); bos=new BufferedOutputStream(fos); oos=new ObjectOutputStream(bos); oos.writeObject(m); System.out.println("object serialized"); amlist=new MemberAccountList(); oos.close(); } catch(Exception ex){ ex.printStackTrace(); } Reading objects: try{ MemberAccount m1; file=new File("account4.dat");//add your code here fis=new FileInputStream(file); bis=new BufferedInputStream(fis); ois=new ObjectInputStream(bis); System.out.println(ois.readObject()); while(ois.readObject()!=null){ m1=(MemberAccount)ois.readObject(); System.out.println(m1.toString()); }/mList.addElement(m1); // Here we have the issue throwing null pointer exception Enumeration elist=mList.elements(); while(elist.hasMoreElements()){ obj=elist.nextElement(); System.out.println(obj.toString()); }/ } catch(ClassNotFoundException e){ } catch(EOFException e){ System.out.println("end"); } catch(Exception ex){ ex.printStackTrace(); }

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  • How to ask BeanUtils to ignore null values

    - by Calm Storm
    Using Commons beanUtils I would like to know how to ask any converter say the Dateconverter to ignore null values and use null as default. As an example consider a public class, public class X { private Date date1; private String string1; //add public getters and setters } and my convertertest as, public class Apache { @Test public void testSimple() throws Exception { X x1 = new X(), x2 = new X(); x1.setString1("X"); x1.setDate1(null); org.apache.commons.beanutils.BeanUtils.copyProperties(x2, x1); //throws ConversionException System.out.println(x2.getString1()); System.out.println(x2.getDate1()); } } The above throws a NPE since the date happens to be null. This looks a very primitive scenario to me which should be handled by default (as in, I would expect x2 to have null value for date1). The doco tells me that I can ask the converter to do this. Can someone point me as to the best way for doing this ? I dont want to get hold of the Converter and isUseDefault() to be true because then I have to do it for all Date, Enum and many other converters !

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  • Basic jUnit Questions

    - by Epitaph
    I was testing a String multiplier class with a multiply() method that takes 2 numbers as inputs (as String) and returns the result number (as String) `public String multiply(String num1, String num2); I have done the implementation and created a test class with the following test cases involving the input String parameter as 1) valid numbers 2) characters 3) special symbol 4) empty string 5) Null value 6) 0 7) Negative number 8) float 9) Boundary values 10) Numbers that are valid but their product is out of range 11) numbers will + sign (+23) 1) I'd like to know if "each and every" assertEquals() should be in it's own test method? Or, can I group similar test cases like testInvalidArguments() to contains all asserts involving invalid characters since ALL of them throw the same NumberFormatException ? 2) If testing an input value like character ("a"), do I need to include test cases for ALL scenarios? "a" as the first argument "a" as the second argument "a" and "b" as the 2 arguments 3) As per my understanding, the benefit of these unit tests is to find out the cases where the input from a user might fail and result in an exception. And, then we can give the user with a meaningful message (asking them to provide valid input) instead of an exception. Is that the correct? And, is it the only benefit? 4) Are the 11 test cases mentioned above sufficient? Did I miss something? Did I overdo? When is enough? 5) Following from the above point, have I successfully tested the multiply() method?

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  • Casting To The Correct Subclass

    - by kap
    Hi Guys I hava a supeclass called Car with 3 subclasses. class Ford extends Car{ } class Chevrolet extends Car{ } class Audi extends Car{ } Now i have a function called printMessge(Car car) which will print a message of a particular car type. In the implementation i use if statements to test the instance of the classes like this. public int printMessge(Car car){ if((Ford)car instanceof Ford){ // print ford }else if((Chevrolet)car instanceof Chevrolet){ // print chevrolet }else if((Audi)car instanceof Audi){ // print Audi } } for instance if i call it for the first time with Ford printMessge(new Ford()), it prints the ford message but when i call it with printMessge(new Chevrolet()), i get EXCEPTION from the first if statement that Chevrolet cannot be cast to Ford. What am i doing wrong and what is the best way. thanks

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  • Compute the Length of Largest substring that starts and ends with the same substring

    - by Deepak
    Hi People, Below is the Problem Statement: PS: Given a string and a non-empty substring sub, compute recursively the largest substring which starts and ends with sub and return its length. Examples: strDist("catcowcat", "cat") ? 9 strDist("catcowcat", "cow") ? 3 strDist("cccatcowcatxx", "cat") ? 9 Below is my Code: (Without recursion)//since i found it hard to implement with recursion. public int strDist(String str, String sub){ int idx = 0; int max; if (str.isEmpty()) max = 0; else max=1; while ((idx = str.indexOf(sub, idx)) != -1){ int previous=str.indexOf(sub, idx); max = Math.max(max,previous); idx++; } return max; } Its working for few as shown below but returns FAIL for others. Expected This Run strDist("catcowcat", "cat") ? 9 6 FAIL strDist("catcowcat", "cow") ? 3 3 OK strDist("cccatcowcatxx", "cat") ? 9 8 FAIL strDist("abccatcowcatcatxyz", "cat") ? 12 12 OK strDist("xyx", "x") ? 3 2 FAIL strDist("xyx", "y") ? 1 1 OK strDist("xyx", "z") ? 0 1 FAIL strDist("z", "z") ? 1 1 OK strDist("x", "z") ? 0 1 FAIL strDist("", "z") ? 0 0 OK strDist("hiHellohihihi", "hi") ? 13 11 FAIL strDist("hiHellohihihi", "hih") ? 5 9 FAIL strDist("hiHellohihihi", "o") ? 1 6 FAIL strDist("hiHellohihihi", "ll") ? 2 4 FAIL Could you let me whats wrong with the code and how to return the largest substring that begins and ends with sub with its respective length.

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