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  • JPA concatenating table names for parent/child @OneToMany

    - by Robert
    We are trying to use a basic @OneToMany relationship: @Entity @Table(name = "PARENT_MESSAGE") public class ParentMessage { @Id @Column(name = "PARENT_ID") @GeneratedValue(strategy = GenerationType.IDENTITY) private Integer parentId; @OneToMany(fetch=FetchType.LAZY) private List childMessages; public List getChildMessages() { return this.childMessages; } ... } @Entity @Table(name = "CHILD_MSG_USER_MAP") public class ChildMessage { @Id @Column(name = "CHILD_ID") @GeneratedValue(strategy = GenerationType.IDENTITY) private Integer childId; @ManyToOne(optional=false,targetEntity=ParentMessage.class,cascade={CascadeType.REFRESH}, fetch=FetchType.LAZY) private ParentMessage parentMsg; public ParentMessage getParentMsg() { return parentMsg; } ... } ChildMessage child = new ChildMessage(); em.getTransaction().begin(); ParentMessage parentMessage = (ParentMessage) em.find(ParentMessage.class, parentId); child.setParentMsg(parentMessage); List list = parentMessage.getChildMessages(); if(list == null) list = new ArrayList(); list.add(child); em.getTransaction().commit(); We receive the following error. Why is OpenJPA concatenating the table names to APP.PARENT_MESSAGE_CHILD_MSG_USER_MAP? Of course that table doesn't exist.. the tables defined are APP.PARENT_MESSAGE and APP.CHILD_MSG_USER_MAP Caused by: org.apache.openjpa.lib.jdbc.ReportingSQLException: Table/View 'APP.PARENT_MESSAGE_CHILD_MSG_USER_MAP' does not exist. {SELECT t1.CHILD_ID, t1.PARENT_ID, t1.CREATED_TIME, t1.USER_ID FROM APP.PARENT_MESSAGE_CHILD_MSG_USER_MAP t0 INNER JOIN APP.CHILD_MSG_USER_MAP t1 ON t0.CHILDMESSAGES_CHILD_ID = t1.CHILD_ID WHERE t0.PARENTMESSAGE_PARENT_ID = ?} [code=30000, state=42X05]

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  • Java: how to have try-catch as conditional in for-loop?

    - by HH
    I know how to solve the problem by comparing size to an upper bound but I want a conditional that look for an exception. If an exception occur in conditinal, I want to exit. import java.io.*; import java.util.*; public class listTest{ public static void main(String[] args){ Stack<Integer> numbs=new Stack<Integer>(); numbs.push(1); numbs.push(2); for(int count=0,j=0;try{((j=numbs.pop())<999)}catch(Exception e){break;}&& !numbs.isEmpty(); ){ System.out.println(j); } // I waited for 1 to be printed, not 2. } } Some Errors javac listTest.java listTest.java:10: illegal start of expression for(int count=0,j=0;try{((j=numbs.pop())<999)}catch(Exception e){break;}&& ^ listTest.java:10: illegal start of expression for(int count=0,j=0;try{((j=numbs.pop())<999)}catch(Exception e){break;}&& ^

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  • how do call a polymorphic function from an agnostic function?

    - by sds
    I have a method foo void foo (String x) { ... } void foo (Integer x) { ... } and I want to call it from a method which does not care about the argument: void bar (Iterable i) { ... for (Object x : i) foo(x); // this is the only time i is used ... } the code above complains that that foo(Object) is not defined and when I add void foo (Object x) { throw new Exception; } then bar(Iterable<String>) calls that instead of foo(String) and throws the exception. How do I avoid having two textually identical definitions of bar(Iterable<String>) and bar(Iterable<Integer>)? I thought I would be able to get away with something like <T> void bar (Iterable<T> i) { ... for (T x : i) foo(x); // this is the only time i is used ... } but then I get cannot find foo(T) error.

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  • VB dataset issue

    - by Gabriel
    Hi. The idea was to create a message box that stores my user name, message, and post datetime into the database as messages are sent. Soon came to realise, what if the user changed his name? So I decided to use the user id (icn) to identify the message poster instead. However, my chunk of codes keep giving me the same error. Says that there are no rows in the dataset ds2. I've tried my Query on my SQL and it works perfectly so I really really need help to spot the error in my chunk of codes here. Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load Dim name As String Dim icn As String Dim message As String Dim time As String Dim tags As String = "" Dim strConn As System.Configuration.ConnectionStringSettings strConn = ConfigurationManager.ConnectionStrings("ufadb") Dim conn As SqlConnection = New SqlConnection(strConn.ToString()) Dim cmd As New SqlCommand("Select * From Message", conn) Dim daMessages As SqlDataAdapter = New SqlDataAdapter(cmd) Dim ds As New DataSet cmd.Connection.Open() daMessages.Fill(ds, "Messages") cmd.Connection.Close() If ds.Tables("Messages").Rows.Count > 0 Then Dim n As Integer = ds.Tables("Messages").Rows.Count Dim i As Integer For i = 0 To n - 1 icn = ds.Tables("Messages").Rows(i).Item("icn") Dim cmd2 As New SqlCommand("SELECT name FROM Member inner join Message ON Member.icn = Message.icn WHERE message.icn = @icn", conn) cmd2.Parameters.AddWithValue("@icn", icn) Dim daName As SqlDataAdapter = New SqlDataAdapter(cmd2) Dim ds2 As New DataSet cmd2.Connection.Open() daName.Fill(ds2, "PosterName") cmd2.Connection.Close() name = ds2.Tables("PosterName").Rows(0).Item("name") message = ds.Tables("Messages").Rows(i).Item("message") time = ds.Tables("Messages").Rows(i).Item("timePosted") tags = time + vbCrLf + name + ": " + vbCrLf + message + vbCrLf + tags Next txtBoard.Text = tags Else txtBoard.Text = "nothing to display" End If End Sub Help will be very much appreciated as I have been on this simple problem for 2 days.

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  • Read specific line from text file, according to Checked Listbox selection number.

    - by Manolis
    Heya, i want to create an application which will read a specific line from a text file and show it in a textbox. The line will be chosen according to the number of the listbox selection i will make. Here's the code: Public Class Form1 Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load End Sub Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click Dim i As Integer For i = 0 To Me.CheckedListBox1.CheckedIndices.Count - 1 Me.CheckedListBox1.SetItemChecked(Me.CheckedListBox1.CheckedIndices(0),False) Next i End Sub Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click If CheckedListBox1.CheckedItems.Count <> 0 Then Dim reader As New System.IO.StreamReader(CurDir() & "\" & "READ.txt") Dim x As Integer Dim s As String = "" For x = 0 To CheckedListBox1.CheckedItems.Count - 1 s = s & "Answer " & (x + 1).ToString & ") " & CheckedListBox1.CheckedItems(x).ToString & ControlChars.CrLf & reader.ReadLine() & ControlChars.CrLf & ControlChars.CrLf Next x Answer.Text = (s) Else MessageBox.Show("Please select questions.", "Error", _ MessageBoxButtons.OK, _ MessageBoxIcon.Information) Return End If End Sub End Class So lets say i 'check' the first, second, and fifth items from the checked listbox, i want it to read from the text file the first, second, and fifth lines of text and show them in the textbox. The current code just reads line 1, 2, 3 (...) in order, no matter what item i have 'checked'. Thanks in advance!

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  • ArrayList<Int> Collections.Sort and LineNumberReader Help How to

    - by user1819551
    I have a issue i can't get it to work now let going to the point a explain in the code thanks. This is my class: what I want to do is insert the Integers sort the list and buffer writer in a column with out coma. Now I getting this: [1110018, 1110032, 1110056, 1110059, 1110063, 1110085, 1110096, 1110123, 1110125, 1110185, 1110456, 1110459] I want like this: 111xxxxx 111xxxx xxxx....... I can't do it in single array, have to be in ArrayList. This is my collecting: list.addNumbers(numbers); list.display(); This is my writer: Is buffered coma.write("\n"+list.display()); coma.flush();<br/> Here is my class: public class IdCount {<br/> private ArrayList<Integer> properNumber = new ArrayList<>(); public void addNumbers(Integer numbers) { properNumber.add(numbers); Collections.sort(properNumber); } public String display() { //(I try .toString() Not work) return properNumber.toString(); } My second issue is LineNumberReader: This is my collecting and my writing: try { Reader input = new BufferedReader( new FileReader(inputFile)); try (Scanner in = new Scanner(input)) { while (in.hasNext()) { //(More Code) asp = new LineNumberReader(input); int rom = 0; while (asp.readLine()!=null){ rom++; } System.out.println(rom); coma.write(rom); This one will not write anything an my System Print give me only 12 0 in column.

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  • How do I establish table association in JPA / Hibernate with existing database?

    - by Paperino
    Currently I have two tables in my database Encounters and Referrals: There is a one to many relationship between these two tables. Currently they are linked together with foreign keys. Right now I have public class Encounter extends JPASupport implements java.io.Serializable { @Column(name="referralid", unique=false, nullable=true, insertable=true, updatable=true) public Integer referralid; } But what I really want is public class Encounter extends JPASupport implements java.io.Serializable { .......... @OneToMany(cascade=CascadeType.PERSIST) public Set<Referrals> referral; ............ } So that I can eventually do a query like this: List<Encounter> cases = Encounter.find( "select distinct p from Encounter p join p.referrals as t where t.caseid =103" ).fetch(); How do I tell JPA that even though I have non-standard column names for my foreign keys and primary keys that its the object models that I want linked, not simply the integer value for the keys? Does this make sense? I hope so. Thanks in advanced!

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  • Passing a parameter in a Report's Open Event to a parameter query (Access 2007)

    - by JPM
    Hi there, I would like to know if there is a way to set the parameters in an Access 2007 query using VBA. I am new to using VBA in Access, and I have been tasked with adding a little piece of functionality to an existing app. The issue I am having is that the same report can be called in two different places in the application. The first being on a command button on a data entry form, the other from a switchboard button. The report itself is based on a parameter query that has requires the user to enter a Supplier ID. The user would like to not have to enter the Supplier ID on the data entry form (since the form displays the Supplier ID already), but from the switchboard, they would like to be prompted to enter a Supplier ID. Where I am stuck is how to call the report's query (in the report's open event) and pass the SupplierID from the form as the parameter. I have been trying for a while, and I can't get anything to work correctly. Here is my code so far, but I am obviously stumped. Private Sub Report_Open(Cancel As Integer) Dim intSupplierCode As Integer 'Check to see if the data entry form is open If CurrentProject.AllForms("frmExample").IsLoaded = True Then 'Retrieve the SupplierID from the data entry form intSupplierCode = Forms![frmExample]![SupplierID] 'Call the parameter query passing the SupplierID???? DoCmd.OpenQuery "qryParams" Else 'Execute the parameter query as normal DoCmd.OpenQuery "qryParams"????? End If End Sub I've tried Me.SupplierID = intSupplierCode, and although it compiles, it bombs when I run it. And here is my SQL code for the parameter query: PARAMETERS [Enter Supplier] Long; SELECT Suppliers.SupplierID, Suppliers.CompanyName, Suppliers.ContactName, Suppliers.ContactTitle FROM Suppliers WHERE (((Suppliers.SupplierID)=[Enter Supplier])); I know there are ways around this problem (and probably an easy way as well) but like I said, my lack of experience using Access and VBA makes things difficult. If any of you could help, that would be great!

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  • How can I update a record using a correlated subquery?

    - by froadie
    I have a function that accepts one parameter and returns a table/resultset. I want to set a field in a table to the first result of that recordset, passing in one of the table's other fields as the parameter. If that's too complicated in words, the query looks something like this: UPDATE myTable SET myField = (SELECT TOP 1 myFunctionField FROM fn_doSomething(myOtherField) WHERE someCondition = 'something') WHERE someOtherCondition = 'somethingElse' In this example, myField and myOtherField are fields in myTable, and myFunctionField is a field return by fn_doSomething. This seems logical to me, but I'm getting the following strange error: 'myOtherField' is not a recognized OPTIMIZER LOCK HINTS option. Any idea what I'm doing wrong, and how I can accomplish this? *UPDATE: * Based on Anil Soman's answer, I realized that the function is expecting a string parameter and the field being passed is an integer. I'm not sure if this should be a problem as an explicit call to the function using an integer value works - e.g. fn_doSomething(12345) seems to automatically cast the number to an string. However, I tried to do an explicit cast: UPDATE myTable SET myField = (SELECT TOP 1 myFunctionField FROM fn_doSomething(CAST(myOtherField AS varchar(1000))) WHERE someCondition = 'something') WHERE someOtherCondition = 'somethingElse' Now I'm getting the following error: Line 5: Incorrect syntax near '('.

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  • DDD and Entity Base, Model using multiple identity types

    - by Thomas
    I have a model that looks like this: public interface IEntity { int Id { get; set; } } Then the idea is to have my entities inherit from this interface: public class User : IEntity { public int Id { get; set; } } However, one of my entities actually has a Guid as an identifier. public class UserSession { public Guid Id { get; set; } } I really would like all my entities inheriting from the same interface but that would force me to add an integer based identity column to the UserSession which is unnecessary since Guid is the identity, but it would keep the domain model nice since all entities would inherit from the same base. What options do I have in this scenario? Can I have two base interfaces, one for int and one for Guid? Should I add an identity column into the UserSession entity although it is unnecessary? I need the Guid so I can't just get rid of it and replace it with and integer. Any thoughts on best practices?

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  • copy rows before updating them to preserve archive in Postgres

    - by punkish
    I am experimenting with creating a table that keeps a version of every row. The idea is to be able to query for how the rows were at any point in time even if the query has JOINs. Consider a system where the primary resource is books, that is, books are queried for, and author info comes along for the ride CREATE TABLE authors ( author_id INTEGER NOT NULL, version INTEGER NOT NULL CHECK (version > 0), author_name TEXT, is_active BOOLEAN DEFAULT '1', modified_on TIMESTAMP DEFAULT CURRENT_TIMESTAMP, PRIMARY KEY (author_id, version) ) INSERT INTO authors (author_id, version, author_name) VALUES (1, 1, 'John'), (2, 1, 'Jack'), (3, 1, 'Ernest'); I would like to be able to update the above like so UPDATE authors SET author_name = 'Jack K' WHERE author_id = 1; and end up with 2, 1, Jack, t, 2012-03-29 21:35:00 2, 2, Jack K, t, 2012-03-29 21:37:40 which I can then query with SELECT author_name, modified_on FROM authors WHERE author_id = 2 AND modified_on < '2012-03-29 21:37:00' ORDER BY version DESC LIMIT 1; to get 2, 1, Jack, t, 2012-03-29 21:35:00 Something like the following doesn't really work CREATE OR REPLACE FUNCTION archive_authors() RETURNS TRIGGER AS $archive_author$ BEGIN IF (TG_OP = 'UPDATE') THEN -- The following fails because author_id,version PK already exists INSERT INTO authors (author_id, version, author_name) VALUES (OLD.author_id, OLD.version, OLD.author_name); UPDATE authors SET version = OLD.version + 1 WHERE author_id = OLD.author_id AND version = OLD.version; RETURN NEW; END IF; RETURN NULL; -- result is ignored since this is an AFTER trigger END; $archive_author$ LANGUAGE plpgsql; CREATE TRIGGER archive_author AFTER UPDATE OR DELETE ON authors FOR EACH ROW EXECUTE PROCEDURE archive_authors(); How can I achieve the above? Or, is there a better way to accomplish this? Ideally, I would prefer to not create a shadow table to store the archived rows.

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  • Optimize LINQ Query for use with jQuery Autocomplete

    - by rockinthesixstring
    I'm working on building an HTTPHandler that will serve up plain text for use with jQuery Autocomplete. I have it working now except for when I insert the first bit of text it does not take me to the right portion of the alphabet. Example: If I enter Ne my drop down returns Nlabama Arkansas Notice the "N" from Ne and the "labama" from "Alabama" As I type the third character New, then the jQuery returns the "N" section of the results. My current code looks like this Public Sub ProcessRequest(ByVal context As System.Web.HttpContext) Implements System.Web.IHttpHandler.ProcessRequest ' the page contenttype is plain text' HttpContext.Current.Response.ContentType = "text/plain" ' store the querystring as a variable' Dim qs As Nullable(Of Integer) = Integer.TryParse(HttpContext.Current.Request.QueryString("ID"), Nothing) ' use the RegionsDataContext' Using RegionDC As New DAL.RegionsDataContext 'create a (q)uery variable' Dim q As Object ' if the querystring PID is not blank' ' then we want to return results based on the PID' If Not qs Is Nothing Then ' that fit within the Parent ID' q = (From r In RegionDC.bt_Regions _ Where r.PID = qs _ Select r.Region).ToArray ' now we loop through the array' ' and write out the ressults' For Each item In q HttpContext.Current.Response.Write(item & vbCrLf) Next End If End Using End Sub So where I'm at now is the fact that I stumbled on the "Part" portion of the Autocomplete method whereby I should only return information that is contained within the Part. My question is, how would I implement this concept into my HTTPHandler without doing a fresh SQLQuery on every character change? IE: I do the SQL Query on the QueryString("ID"), and then on every subsequent load of the same ID, we just filter down the "Part". http://www.example.com/ReturnRegions.axd?ID=[someID]&Part=[string]

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  • MVVM: where is the best place to integrate an id counter, in ViewModel or Repository or... ?

    - by msfanboy
    Hello, I am using http://loungerepo.codeplex.com/ this library needs a unique id when I persist my entities to the repository. I decided for integer not Guid. The question is now where do I retrieve a new integer and how do I do it? This is my current approach in the SchoolclassAdministrationViewModel.cs: public SchoolclassAdministrationViewModel() { _schoolclassRepo = new SchoolclassRepository(); _pupilRepo = new PupilRepository(); _subjectRepo = new SubjectRepository(); _currentSchoolclass = new SchoolclassModel(); _currentPupil = new PupilModel(); _currentSubject = new SubjectModel(); ... } private void AddSchoolclass() { // get the last free id for a schoolclass entity _currentSchoolclass.SchoolclassID = _schoolclassRepo.LastID; // add the new schoolclass entity to the repository _schoolclassRepo.Add(SchoolclassModel.SchoolclassModelToSchoolclass(_currentSchoolclass)); // add the new schoolclass entity to the ObservableCollection bound to the View Schoolclasses.Add(_currentSchoolclass); // Create a new schoolclass entity and the bound UI controls content gets cleaned CurrentSchoolclass = new SchoolclassModel(); } public class SchoolclassRepository : IRepository<Schoolclass> { private int _lastID; public SchoolclassRepository() { _lastID = FetchLastId(); } public void Add(Schoolclass entity) { //repo.Store(entity); } private int FetchLastId() { return // repo.GetIDOfLastEntryAndDoInc++ } public int LastID { get { return _lastID; } } } Explanation: Every time the user switches to the SchoolclassAdministrationViewModel which is datatemplated with a UserControl the saVM Ctor is called and the schoolclass repository is created wherein the FetchLastId() is called and I am up to date with the last ID doing a inc++ on it to get the free one... Do you have any better ideas? What I do not like about my current apporach: -Having a private method in repositry class because a repositry is to fetch data only not "entity logic" like the counter - Having to access from the ViewModel a public property - located in the repository -, actually its not the ViewModel concern to get a entity id and assign it. Actually the ViewModel should ask for a schoolclass POCO and get a SchoolclassModel to bind to the UI. But then I have again to re-read the Schoolclass properties into the SchoolclassModel properties what I want to avoid.

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  • using ini file in vb6, problem with path to file

    - by DrPut
    I have read many articles about how to use an INI file within my VB6 project. I don't have a problem with the methods, my problem is how to make the EXE file find the INI file. I don't want to hard code the path in the program. I simply want the EXE to expect the INI file to be present in the same folder the EXE is executed from. When I run the program from inside VB6 IDE, the INI is found and processed. When I compile the program and run the EXE, nothing is found. My code looks like: gServer = sGetINI(sINIFile, "TOOLBOM", "ServerName", "?") where TOOLBOM is the [Section] and "ServerName" is the key for the value. I obtained the following code for the API: Rem API DECLARATIONS Declare Function GetPrivateProfileString Lib "kernel32" Alias _ "GetPrivateProfileStringA" (ByVal lpApplicationName _ As String, ByVal lpKeyName As Any, ByVal lpDefault _ As String, ByVal lpReturnedString As String, ByVal _ nSize As Long, ByVal lpFileName As String) As Long Declare Function WritePrivateProfileString Lib "kernel32" Alias _ "WritePrivateProfileStringA" (ByVal lpApplicationName _ As String, ByVal lpKeyName As Any, ByVal lpString As Any, _ ByVal lpFileName As String) As Long Public Function sGetINI(sINIFile As String, sSection As String, sKey _ As String, sDefault As String) As String Dim sTemp As String * 256 Dim nLength As Integer sTemp = Space$(256) nLength = GetPrivateProfileString(sSection, sKey, sDefault, sTemp, _ 255, sINIFile) sGetINI = Left$(sTemp, nLength) End Function Public Sub writeINI(sINIFile As String, sSection As String, sKey _ As String, sValue As String) Dim n As Integer Dim sTemp As String sTemp = sValue Rem Replace any CR/LF characters with spaces For n = 1 To Len(sValue) If Mid$(sValue, n, 1) = vbCr Or Mid$(sValue, n, 1) = vbLf _ Then Mid$(sValue, n) = " " Next n n = WritePrivateProfileString(sSection, sKey, sTemp, sINIFile) End Sub

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  • Creating a function in Postgresql that does not return composite values

    - by celenius
    I'm learning how to write functions in Postgresql. I've defined a function called _tmp_myfunction() which takes in an id and returns a table (I also define a table object type called _tmp_mytable) -- create object type to be returned CREATE TYPE _tmp_mytable AS ( id integer, cost double precision ); -- create function which returns query CREATE OR REPLACE FUNCTION _tmp_myfunction( id integer ) RETURNS SETOF _tmp_mytable AS $$ BEGIN RETURN QUERY SELECT id, cost FROM sales WHERE id = sales.id; END; $$ LANGUAGE plpgsql; This works fine when I use one id and call it using the following approach: SELECT * FROM _tmp_myfunction(402); What I would like to be able to do is to call it, but to use a column of values instead of just one value. However, if I use the following approach I end up with all values of the table in one column, separated by commas: -- call function using all values in a column SELECT _tmp_myfunction(t.id) FROM transactions as t; I understand that I can get the same result if I use SELECT _tmp_myfunction(402); instead of SELECT * FROM _tmp_myfunction(402); but I don't know how to construct my query in such a way that I can separate out the results.

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  • Is it safe to silently catch ClassCastException when searching for a specific value?

    - by finnw
    Suppose I am implementing a sorted collection (simple example - a Set based on a sorted array.) Consider this (incomplete) implementation: import java.util.*; public class SortedArraySet<E> extends AbstractSet<E> { @SuppressWarnings("unchecked") public SortedArraySet(Collection<E> source, Comparator<E> comparator) { this.comparator = (Comparator<Object>) comparator; this.array = source.toArray(); Collections.sort(Arrays.asList(array), this.comparator); } @Override public boolean contains(Object key) { return Collections.binarySearch(Arrays.asList(array), key, comparator) >= 0; } private final Object[] array; private final Comparator<Object> comparator; } Now let's create a set of integers Set<Integer> s = new SortedArraySet<Integer>(Arrays.asList(1, 2, 3), null); And test whether it contains some specific values: System.out.println(s.contains(2)); System.out.println(s.contains(42)); System.out.println(s.contains("42")); The third line above will throw a ClassCastException. Not what I want. I would prefer it to return false (as HashSet does.) I can get this behaviour by catching the exception and returning false: @Override public boolean contains(Object key) { try { return Collections.binarySearch(Arrays.asList(array), key, comparator) >= 0; } catch (ClassCastException e) { return false; } } Assuming the source collection is correctly typed, what could go wrong if I do this?

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  • Javascript CS-PRNG - 64-bit random

    - by Jack
    Hi, I need to generate a cryptographically secure 64-bit unsigned random integer in Javascript. The first problem is that Javascript only allows 64-bit signed integers, so 9223372036854775808 is the biggest supported integer without going into floating point use I think? To fix this I can use a big number library, no problem. My Method: var randNum = SHA256( randBigInt(128, 0) ) % 2^64; Where SHA256() is a secure hash function and randBigInt() is defined below as a non-crypto PRNG, im giving it a 128bit seed so brute force shouldn't be a problem. randBigInt(n,s) //return an n-bit random BigInt (n>=1). If s=1, then the most significant of those n bits is set to 1. Is this a secure method to generate a cryptographically secure 64-bit random int? And importantly does taking the 2^64 mod guarantee 100% I have a 64-bit number? An abstract example, say this number is prime (it isn't i know), I will use it in the Galois Field [2^p], where p must be 64bits so that every possible 1-63bit number is a field element. In this query, my random int must be larger than any 63-bit number. And Im not sure im correct in taking the 2^64 mod of a 256bit hash output. Thanks (hope that makes sense)

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  • Django unit testing: South-migrated DB works in MySQL, throws duplicate PK error in PostGreSQL. Am I

    - by unclaimedbaggage
    Hi folks, (Worth starting off with a disclaimer: I'm very new to PostGreSQL) I have a django site which involves a standard app/tests.py testing file. If I migrate the DB to MySQL (through South),, the tests all pass. However in PostGresQL, I'm getting the following error: IntegrityError: duplicate key value violates unique constraint "business_contact_pkey" Note this happens while unit testing only - the actual page runs fine in both MySQL & PostGresql. Really having a heckuva time figuring this one out. Anyone have ideas? Below are the Postgresql "\d business_contact" & offending tests.py method if they help. No changes made to either DB except the (same) South migrations Thanks first_name | character varying(200) | not null mobile_phone | character varying(100) | surname | character varying(200) | not null business_id | integer | not null created | timestamp with time zone | not null deleted | boolean | not null default false updated | timestamp with time zone | not null slug | character varying(150) | not null phone | character varying(100) | email | character varying(75) | id | integer | not null default nextval('business_contact_id_seq'::regclass) Indexes: "business_contact_pkey" PRIMARY KEY, btree (id) "business_contact_slug_key" UNIQUE, btree (slug) "business_contact_business_id" btree (business_id) Foreign-key constraints: "business_id_refs_id_772cc1b7b40f4b36" FOREIGN KEY (business_id) REFERENCES business(id) DEFERRABLE INITIALLY DEFERRED Referenced by: TABLE "business" CONSTRAINT "primary_contact_id_refs_id_dfaf59c4041c850" FOREIGN KEY (primary_contact_id) REFERENCES business_contact(id) DEFERRABLE INITIALLY DEFERRED TEST DEF: def test_add_business_contact(self): """ Add a business contact """ contact_slug = 'test-new-contact-added-new-adf' business_id = 1 business = Business.objects.get(id=business_id) postdata = { 'first_name': 'Test', 'surname': 'User', 'business': '1', 'slug': contact_slug, 'email': '[email protected]', 'phone': '12345678', 'mobile_phone': '9823452', 'business': 1, 'business_id': 1, } #Test to ensure contacts that should not exist are not returned contact_not_exists = Contact.objects.filter(slug=contact_slug) self.assertFalse(contact_not_exists) #Add the contact and ensure it is present in the DB afterwards """ contact_add_url = '%s%s/contact/add/' % (settings.BUSINESS_URL, business.slug) self.client.post(contact_add_url, postdata) added_contact = Contact.objects.filter(slug=contact_slug) print added_contact try: self.assertTrue(added_contact) except: formset = ContactForm(postdata) print formset.errors self.assertFalse(True, "Contact not found in the database - most likely, the post values in the test didn't validate against the form")

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  • VB.NET trying simple captcha

    - by Pride Grimm
    I'm trying to write a simple captcha program in vb.net. I'm just wanting to make an image from random numbers and display it, check the answer, and then proceed. I'm pretty new to vb.net, so I found some code to generate the information. I will cite the owner when I find it again (http://www.knowlegezone.com/80/article/Technology/Software/Asp-Net/Simple-ASP-NET-CAPTCHA-Tutorial) This is in the onload() of default2.aspx Public Sub returnNumer() Dim num1 As New Random Dim num2 As New Random Dim numQ1 As Integer Dim numQ2 As Integer Dim QString As String numQ1 = num1.Next(10, 15) numQ2 = num2.Next(17, 31) QString = numQ1.ToString + " + " + numQ2.ToString + " = " Session("answer") = numQ1 + numQ2 Dim bitmap As New Bitmap(85, 35) Dim Grfx As Graphics = Graphics.FromImage(bitmap) Dim font As New Font("Arial", 18, FontStyle.Bold, GraphicsUnit.Pixel) Dim Rect As New Rectangle(0, 0, 100, 50) Grfx.FillRectangle(Brushes.Brown, Rect) Grfx.DrawRectangle(Pens.PeachPuff, Rect) ' Border Grfx.DrawString(QString, font, Brushes.Azure, 0, 0) Response.ContentType = "Image/jpeg" bitmap.Save(Response.OutputStream, System.Drawing.Imaging.ImageFormat.Jpeg) bitmap.Dispose() Grfx.Dispose() End Sub So I put this in a separate page, like this This all works find and dandy, but when I get the answer from the session like this Dim literal As String = Convert.ToString(Session("answer")) It's always one behind. So if The images adds to 32, the answer in session isn't 32. But after a refresh (and a new image) the session("answer") will be 32. Is there a way to refresh the session on page 1, after the default2.aspx loads? Is there a better way to do this? I though about trying to run the code all on one page, and trying to set the src of and image to returnNumber(), but I need a bit of help on that one.

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  • Indices instead of pointers in STL containers?

    - by zvrba
    Due to specific requirements [*], I need a singly-linked list implementation that uses integer indices instead of pointers to link nodes. The indices are always interpreted with respect to a vector containing the list nodes. I thought I might achieve this by defining my own allocator, but looking into the gcc's implementation of , they explicitly use pointers for the link fields in the list nodes (i.e., they do not use the pointer type provided by the allocator): struct _List_node_base { _List_node_base* _M_next; ///< Self-explanatory _List_node_base* _M_prev; ///< Self-explanatory ... } (For this purpose, the allocator interface is also deficient in that it does not define a dereference function; "dereferencing" an integer index always needs a pointer to the underlying storage.) Do you know a library of STL-like data structures (i am mostly in need of singly- and doubly-linked list) that use indices (wrt. a base vector) instead of pointers to link nodes? [*] Saving space: the lists will contain many 32-bit integers. With two pointers per node (STL list is doubly-linked), the overhead is 200%, or 400% on 64-bit platform, not counting the overhead of the default allocator.

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  • Which Queue implementation to use in Java?

    - by devoured elysium
    I need to use a FIFO structure in my application. It needs to have at most 5 elements. I'd like to have something easy to use (I don't care for concurrency) that implements the Collection interface. I've tried the LinkedList, that seems to come from Queue, but it doesn't seem to allow me to set it's maximum capacity. It feels as if I just want at max 5 elements but try to add 20, it will just keep increasing in size to fit it. I'd like something that'd work the following way: XQueue<Integer> queue = new XQueue<Integer>(5); //where 5 is the maximum number of elements I want in my queue. for (int i = 0; i < 10; ++i) { queue.offer(i); } for (int i = 0; i < 5; ++i) { System.out.println(queue.poll()); } That'd print: 5 6 7 8 9 Thanks

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  • Are function-local typedefs visible inside C++0x lambdas?

    - by GMan - Save the Unicorns
    I've run into a strange problem. The following simplified code reproduces the problem in MSVC 2010 Beta 2: template <typename T> struct dummy { static T foo(void) { return T(); } }; int main(void) { typedef dummy<bool> dummy_type; auto x = [](void){ bool b = dummy_type::foo(); }; // auto x = [](void){ bool b = dummy<bool>::foo(); }; // works } The typedef I created locally in the function doesn't seem to be visible in the lambda. If I replace the typedef with the actual type, it works as expected. Here are some other test cases: // crashes the compiler, credit to Tarydon int main(void) { struct dummy {}; auto x = [](void){ dummy d; }; } // works as expected int main(void) { typedef int integer; auto x = [](void){ integer i = 0; }; } I don't have g++ 4.5 available to test it, right now. Is this some strange rule in C++0x, or just a bug in the compiler? From the results above, I'm leaning towards bug. Though the crash is definitely a bug. For now, I have filed two bug reports. All code snippets above should compile. The error has to do with using the scope resolution on locally defined scopes. (Spotted by dvide.) And the crash bug has to do with... who knows. :) Update According to the bug reports, they have both been fixed for the next release of Visual Studio 2010.

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  • Doubt about instance creation by using Spring framework ???

    - by Arthur Ronald F D Garcia
    Here goes a command object which needs to be populated from a Spring form public class Person { private String name; private Integer age; /** * on-demand initialized */ private Address address; // getter's and setter's } And Address public class Address { private String street; // getter's and setter's } Now suppose the following MultiActionController @Component public class PersonController extends MultiActionController { @Autowired @Qualifier("personRepository") private Repository<Person, Integer> personRepository; /** * mapped To /person/add */ public ModelAndView add(HttpServletRequest request, HttpServletResponse response, Person person) throws Exception { personRepository.add(person); return new ModelAndView("redirect:/home.htm"); } } Because Address attribute of Person needs to be initialized on-demand, i need to override newCommandObject to create an instance of Person to initiaze address property. Otherwise, i will get NullPointerException @Component public class PersonController extends MultiActionController { /** * code as shown above */ @Override public Object newCommandObject(Class clazz) thorws Exception { if(clazz.isAssignableFrom(Person.class)) { Person person = new Person(); person.setAddress(new Address()); return person; } } } Ok, Expert Spring MVC and Web Flow says Options for alternate object creation include pulling an instance from a BeanFactory or using method injection to transparently return a new instance. First option pulling an instance from a BeanFactory can be written as @Override public Object newCommandObject(Class clazz) thorws Exception { /** * Will retrieve a prototype instance from ApplicationContext whose name matchs its clazz.getSimpleName() */ getApplicationContext().getBean(clazz.getSimpleName()); } But what does he want to say by using method injection to transparently return a new instance ??? Can you show how i implement what he said ??? ATT: I know this funcionality can be filled by a SimpleFormController instead of MultiActionController. But it is shown just as an example, nothing else

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  • Should not a tail-recursive function also be faster?

    - by Balint Erdi
    I have the following Clojure code to calculate a number with a certain "factorable" property. (what exactly the code does is secondary). (defn factor-9 ([] (let [digits (take 9 (iterate #(inc %) 1)) nums (map (fn [x] ,(Integer. (apply str x))) (permutations digits))] (some (fn [x] (and (factor-9 x) x)) nums))) ([n] (or (= 1 (count (str n))) (and (divisible-by-length n) (factor-9 (quot n 10)))))) Now, I'm into TCO and realize that Clojure can only provide tail-recursion if explicitly told so using the recur keyword. So I've rewritten the code to do that (replacing factor-9 with recur being the only difference): (defn factor-9 ([] (let [digits (take 9 (iterate #(inc %) 1)) nums (map (fn [x] ,(Integer. (apply str x))) (permutations digits))] (some (fn [x] (and (factor-9 x) x)) nums))) ([n] (or (= 1 (count (str n))) (and (divisible-by-length n) (recur (quot n 10)))))) To my knowledge, TCO has a double benefit. The first one is that it does not use the stack as heavily as a non tail-recursive call and thus does not blow it on larger recursions. The second, I think is that consequently it's faster since it can be converted to a loop. Now, I've made a very rough benchmark and have not seen any difference between the two implementations although. Am I wrong in my second assumption or does this have something to do with running on the JVM (which does not have automatic TCO) and recur using a trick to achieve it? Thank you.

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  • How to use Comparator in Java to sort

    - by Dan
    I learned how to use the comparable but I'm having difficulty with the Comparator. I am having a error in my code: Exception in thread "main" java.lang.ClassCastException: New.People cannot be cast to java.lang.Comparable at java.util.Arrays.mergeSort(Unknown Source) at java.util.Arrays.sort(Unknown Source) at java.util.Collections.sort(Unknown Source) at New.TestPeople.main(TestPeople.java:18) Here is my code: import java.util.Comparator; public class People implements Comparator{ private int id; private String info; private double price; public People(int newid, String newinfo, double newprice){ setid(newid); setinfo(newinfo); setprice(newprice); } public int getid() { return id; } public void setid(int id) { this.id = id; } public String getinfo() { return info; } public void setinfo(String info) { this.info = info; } public double getprice() { return price; } public void setprice(double price) { this.price = price; } public int compare(Object obj1, Object obj2) { Integer p1 = ((People)obj1).getid(); Integer p2 = ((People)obj2).getid(); if (p1 p2 ){ return 1; } else if (p1 < p2){ return -1; } else return 0; } } import java.util.ArrayList; import java.util.Collections; public class TestPeople { public static void main(String[] args) { ArrayList peps = new ArrayList(); peps.add(new People(123, "M", 14.25)); peps.add(new People(234, "M", 6.21)); peps.add(new People(362, "F", 9.23)); peps.add(new People(111, "M", 65.99)); peps.add(new People(535, "F", 9.23)); Collections.sort(peps); for(int i=0;i I believe it has to do something with the casting in the compare method but I was playing around with it and still could not find the solution

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