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  • Direct comparator in Java out of the box

    - by KARASZI István
    I have a method which needs a Comparator for one of its parameters. I would like to pass a Comparator which does a normal comparison and a reverse comparator which does in reverse. java.util.Collections provides a reverseOrder() this is good for the reverse comparison, but I could not find any normal Comparator. The only solution what came into my mind is Collections.reverseOrder(Collections.reverseOrder()). but I don't like it because the double method calling inside. Of course I could write a NormalComparator like this: public class NormalComparator<T extends Comparable> implements Comparator<T> { public int compare(T o1, T o2) { return o1.compareTo(o2); } } But I'm really surprised that Java doesn't have a solution for this out of the box.

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  • Improve performance of sorting files by extension

    - by DxCK
    With a given array of file names, the most simpliest way to sort it by file extension is like this: Array.Sort(fileNames, (x, y) => Path.GetExtension(x).CompareTo(Path.GetExtension(y))); The problem is that on very long list (~800k) it takes very long to sort, while sorting by the whole file name is faster for a couple of seconds! Theoretical, there is a way to optimize it: instead of using Path.GetExtension() and compare the newly created extension-only-strings, we can provide a Comparison than compares starting from the LastIndexOf('.') without creating new strings. Now, suppose i found the LastIndexOf('.'), i want to reuse native .NET's StringComparer and apply it only to the part on string after the LastIndexOf('.'). Didn't found a way to do that. Any ideas?

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  • C# SortedList, getting value by key

    - by user1004039
    I have SortedList in descending order. public class MyComparer : IComparer<int> { public int Compare(int x, int y) { if (x.CompareTo(y) > 0) return -1; return 1; } } class Program { static void Main(string[] args) { SortedList<int, bool> myList = new SortedList<int, bool>(new MyComparer()); myList.Add(10, true); bool check = myList[10];//In this place an exception "Can't find key" occurs } } When SortedList created without my own IComparer the code works fine and no exception occurs.

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  • How to sort an array or ArrayList<Point> ASC first by x and then by y?

    - by newba
    Hi everyone, I just want to use Collections.sort or Arrays.sort to sort a list of points (class Point) by x first and then by y. I have a class Ponto that implements Comparable like this: public int compareTo(Ponto obj) { Ponto tmp = obj; if (this.x < tmp.x) { return -1; } else if (this.x > tmp.x) { return 1; } return 0; } but now I want to sort by y too after x. How can I do that by modifying the above code? Or is that a better and "clean" way to do this? I also use to pass this code to C++, in which I've created a structure called Point with a equivalent comparable method.

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  • Custom sort logic in OrderBy using LINQ

    - by Bala R
    What would be the right way to sort a list of strings where I want items starting with an underscore '_', to be at the bottom of the list, otherwise everything is alphabetical. Right now I'm doing something like this, autoList.OrderBy(a => a.StartsWith("_") ? "ZZZZZZ"+a : a ) EDIT: I ended up using something like this; optimization suggestions welcome! private class AutoCompleteComparer : IComparer<String> { public int Compare(string x, string y) { if (x.StartsWith("_") && y.StartsWith("_") || (!x.StartsWith("_") && !y.StartsWith("_"))) { return x.CompareTo(y); } else if (x.StartsWith("_")) { return 1; } else if (y.StartsWith("_")) { return -1; } return 0; } }

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  • biginteger calculation problem

    - by murali
    I am using the following code but the parameters are not passed to the methods. BigInteger p = BigInteger.valueOf(0); BigInteger u1 = obj.bigi_calc(g1, l); In this g1,l are long values. The method is private BigInteger bigi_calc(long g1, long l){ BigInteger cal = BigInteger.valueOf(g1); BigInteger cal1= BigInteger.valueOf(l); for(BigInteger f = BigInteger.ONE;f.compareTo(cal1)>0;f=f.add(BigInteger.ONE)){ //BigInteger p= BigInteger.valueOf(0); p = cal.multiply(cal1); System.out.println("check p"+p); } // System.out.println("check p"+p); return p; } The elipse shows that it may be out of sync, but the parameters are not passed to the functions. Can you please help me to solve this problem?

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  • Why is false being returned in this function

    - by Kay
    Hello all, I have this function below which makes it to the second IF function which sets the variable th as true but what is returned is false? Why?! public boolean nodeExist(TreeNode Tree, T value){ boolean th = false; if(Tree.getValue()!= null){ if(value == Tree.getValue()){ th = true; }else{ if(value.compareTo((T) Tree.getValue()) < 0){ nodeExist(Tree.getLeft(), value); }else{ nodeExist(Tree.getRight(), value); } } }else{ th = false; } return th; }

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  • Duel Masters game in Java

    - by Arun Ramasubramanian
    I was trying to make a Duel Masters card game in Java using BlueJ, and came up with a lot of ideas. However, I could not exactly figure out how to sort a deck on basis of the card names in the game. I have an array of Card objects(each has, as its instance variables: String name, int cost, int civ), and I want to sort them based on name. ie: if I have the cards "Pyrofighter Magnus", "Bazagazeal Dragon" and another "Pyrofighter Magnus" in the array, the cards should be sorted on basis of their names. I know that I could use compareTo(), but is there an easier method? Anyone? Remember, the method that sorts the cards should be a modifier.

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  • Delegate Example From C# In Depth Confusion

    - by ChloeRadshaw
    I am looking at this example: List<Product> products = Product. GetSampleProducts() ; products.Sort( (first, second) => first.Name.CompareTo(second. Name) ) ; foreach (Product product in products) { Console. WriteLine(product) ; } What function is actually called in the API when you do that? Does the compiler create a class which implemnents the IComparer interface? I thought delegates were anonymous methods - Here it seems to be an anonymous interface implementation which is casuing confusion

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  • Use Expressions with LINQ to Entities

    - by EltonStoneman
    [Source: http://geekswithblogs.net/EltonStoneman] Recently I've been putting together a generic approach for paging the response from a WCF service. Paging changes the service signature, so it's not as simple as adding a behavior to an existing service in config, but the complexity of the paging is isolated in a generic base class. We're using the Entity Framework talking to SQL Server, so when we ask for a page using LINQ's .Take() method we get a nice efficient SQL query for just the rows we want, with minimal impact on SQL Server and network traffic. We use the maximum ID of the record returned as a high-water mark (rather than using .Skip() to go to the next record), so the approach caters for records being deleted between page requests. In the paged response we include a HasMorePages indicator, computed by comparing the max ID in the page of results to the max ID for the whole resultset - if the latter is bigger, then there are more pages. In some quick performance testing, the paged version of the service performed much more slowly than the unpaged version, which was unexpected. We narrowed it down to the code which gets the max ID for the full resultset - instead of building an efficient MAX() SQL query, EF was returning the whole resultset and then computing the max ID in the service layer. It's easy to reproduce - take this AdventureWorks query:             var context = new AdventureWorksEntities();             var query = from od in context.SalesOrderDetail                         where od.ModifiedDate >= modified                          && od.SalesOrderDetailID.CompareTo(id) > 0                         orderby od.SalesOrderDetailID                         select od;   We can find the maximum SalesOrderDetailID like this:             var maxIdEfficiently = query.Max(od => od.SalesOrderDetailID);   which produces our efficient MAX() SQL query. If we're doing this generically and we already have the ID function in a Func:             Func<SalesOrderDetail, int> idFunc = od => od.SalesOrderDetailID;             var maxIdInefficiently = query.Max(idFunc);   This fetches all the results from the query and then runs the Max() function in code. If you look at the difference in Reflector, the first call passes an Expression to the Max(), while the second call passes a Func. So it's an easy fix - wrap the Func in an Expression:             Expression<Func<SalesOrderDetail, int>> idExpression = od => od.SalesOrderDetailID;             var maxIdEfficientlyAgain = query.Max(idExpression);   - and we're back to running an efficient MAX() statement. Evidently the EF provider can dissect an Expression and build its equivalent in SQL, but it can't do that with Funcs.

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  • Can't change color of sprites in unity

    - by Aceleeon
    I would like to create a script that targets a 2d sprite "enemy" and changes their color to red (slightly opaque red if possible) when you hit tab. I have this code from a 3d tutorial hoping the transition would work. But it does not. I only get the script to cycle the enemy tags but never changes the color of the sprite. I have the code below I'm very new to coding, and any help would be FANTASTIC! HELP! hahah. TL;DR Cant get 3d color targeting to work for 2D. Check out the c#code below using UnityEngine; using System.Collections; using System.Collections.Generic; public class Targetting : MonoBehaviour { public List targets; public Transform selectedTarget; private Transform myTransform; // Use this for initialization void Start () { targets = new List(); selectedTarget = null; myTransform = transform; AddAllEnemies(); } public void AddAllEnemies() { GameObject[] go = GameObject.FindGameObjectsWithTag("Enemy"); foreach(GameObject enemy in go) AddTarget(enemy.transform); } public void AddTarget(Transform enemy) { targets.Add(enemy); } private void SortTargetsByDistance() { targets.Sort(delegate(Transform t1,Transform t2) { return Vector3.Distance(t1.position, myTransform.position).CompareTo(Vector3.Distance(t2.position, myTransform.position)); }); } private void TargetEnemy() { if(selectedTarget == null) { SortTargetsByDistance(); selectedTarget = targets[0]; } else { int index = targets.IndexOf(selectedTarget); if(index < targets.Count -1) { index++; } else { index = 0; } selectedTarget = targets[index]; } } private void SelectTarget() { selectedTarget.GetComponent().color = Color.red; } private void DeselectTarget() { selectedTarget.GetComponent().color = Color.blue; selectedTarget = null; } // Update is called once per frame void Update() { if(Input.GetKeyDown(KeyCode.Tab)) { TargetEnemy(); } } }

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  • Adding Polynomials (Linked Lists)......Bug Help

    - by Brian
    I have written a program that creates nodes that in this class are parts of polynomials and then the two polynomials get added together to become one polynomial (list of nodes). All my code compiles so the only problem I am having is that the nodes are not inserting into the polynomial via the insert method I have in polynomial.java and when running the program it does create nodes and displays them in the 2x^2 format but when it comes to add the polynomials together it displays o as the polynomials, so if anyone can figure out whats wrong and what I can do to fix it it would be much appreciated. Here is the code: import java.util.Scanner; class Polynomial{ public termNode head; public Polynomial() { head = null; } public boolean isEmpty() { return (head == null); } public void display() { if (head == null) System.out.print("0"); else for(termNode cur = head; cur != null; cur = cur.getNext()) { System.out.println(cur); } } public void insert(termNode newNode) { termNode prev = null; termNode cur = head; while (cur!=null && (newNode.compareTo(cur)<0)) { prev = null; cur = cur.getNext(); } if (prev == null) { newNode.setNext(head); head = newNode; } else { newNode.setNext(cur); prev.setNext(newNode); } } public void readPolynomial(Scanner kb) { boolean done = false; double coefficient; int exponent; termNode term; head = null; //UNLINK ANY PREVIOUS POLYNOMIAL System.out.println("Enter 0 and 0 to end."); System.out.print("coefficient: "); coefficient = kb.nextDouble(); System.out.println(coefficient); System.out.print("exponent: "); exponent = kb.nextInt(); System.out.println(exponent); done = (coefficient == 0 && exponent == 0); while(!done) { Polynomial poly = new Polynomial(); term = new termNode(coefficient,exponent); System.out.println(term); poly.insert(term); System.out.println("Enter 0 and 0 to end."); System.out.print("coefficient: "); coefficient = kb.nextDouble(); System.out.println(coefficient); System.out.print("exponent: "); exponent = kb.nextInt(); System.out.println(exponent); done = (coefficient==0 && exponent==0); } } public static Polynomial add(Polynomial p, Polynomial q) { Polynomial r = new Polynomial(); double coefficient; int exponent; termNode first = p.head; termNode second = q.head; termNode sum = r.head; termNode term; while (first != null && second != null) { if (first.getExp() == second.getExp()) { if (first.getCoeff() != 0 && second.getCoeff() != 0); { double addCoeff = first.getCoeff() + second.getCoeff(); term = new termNode(addCoeff,first.getExp()); sum.setNext(term); first.getNext(); second.getNext(); } } else if (first.getExp() < second.getExp()) { sum.setNext(second); term = new termNode(second.getCoeff(),second.getExp()); sum.setNext(term); second.getNext(); } else { sum.setNext(first); term = new termNode(first.getNext()); sum.setNext(term); first.getNext(); } } while (first != null) { sum.setNext(first); } while (second != null) { sum.setNext(second); } return r; } } Here is my Node class: class termNode implements Comparable { private int exp; private double coeff; private termNode next; public termNode(double coefficient, int exponent) { coeff = coefficient; exp = exponent; next = null; } public termNode(termNode inTermNode) { coeff = inTermNode.coeff; exp = inTermNode.exp; } public void setData(double coefficient, int exponent) { coefficient = coeff; exponent = exp; } public double getCoeff() { return coeff; } public int getExp() { return exp; } public void setNext(termNode link) { next = link; } public termNode getNext() { return next; } public String toString() { if (exp == 0) { return(coeff + " "); } else if (exp == 1) { return(coeff + "x"); } else { return(coeff + "x^" + exp); } } public int compareTo(Object other) { if(exp ==((termNode) other).exp) return 0; else if(exp < ((termNode) other).exp) return -1; else return 1; } } And here is my Test class to run the program. import java.util.Scanner; class PolyTest{ public static void main(String [] args) { Scanner kb = new Scanner(System.in); Polynomial r; Polynomial p = new Polynomial(); System.out.println("Enter first polynomial."); p.readPolynomial(kb); Polynomial q = new Polynomial(); System.out.println(); System.out.println("Enter second polynomial."); q.readPolynomial(kb); r = Polynomial.add(p,q); System.out.println(); System.out.print("The sum of "); p.display(); System.out.print(" and "); q.display(); System.out.print(" is "); r.display(); } }

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  • Having trouble returning a value from a method call when sending an array and the program is error out when run in reference to the sort

    - by programmerNOOB
    I am getting the following output when this program is run: Please enter the Social Security Number for taxpayer 0: 111111111 Please enter the gross income for taxpayer 0: 20000 Please enter the Social Security Number for taxpayer 1: 555555555 Please enter the gross income for taxpayer 1: 50000 Please enter the Social Security Number for taxpayer 2: 333333333 Please enter the gross income for taxpayer 2: 5464166 Please enter the Social Security Number for taxpayer 3: 222222222 Please enter the gross income for taxpayer 3: 645641 Please enter the Social Security Number for taxpayer 4: 444444444 Please enter the gross income for taxpayer 4: 29000 Taxpayer # 1 SSN: 111111111, Income is $20,000.00, Tax is $0.00 Taxpayer # 2 SSN: 555555555, Income is $50,000.00, Tax is $0.00 Taxpayer # 3 SSN: 333333333, Income is $5,464,166.00, Tax is $0.00 Taxpayer # 4 SSN: 222222222, Income is $645,641.00, Tax is $0.00 Taxpayer # 5 SSN: 444444444, Income is $29,000.00, Tax is $0.00 Unhandled Exception: System.InvalidOperationException: Failed to compare two elements in the array. --- System.ArgumentException: At least one object must implement IComparable. at System.Collections.Comparer.Compare(Object a, Object b) at System.Collections.Generic.ObjectComparer`1.Compare(T x, T y) at System.Collections.Generic.ArraySortHelper`1.SwapIfGreaterWithItems(T[] keys, IComparer`1 comparer, Int32 a, Int32 b) at System.Collections.Generic.ArraySortHelper`1.QuickSort(T[] keys, Int32 left, Int32 right, IComparer`1 comparer) at System.Collections.Generic.ArraySortHelper`1.Sort(T[] keys, Int32 index, Int32 length, IComparer`1 comparer) --- End of inner exception stack trace --- at System.Collections.Generic.ArraySortHelper`1.Sort(T[] keys, Int32 index, Int32 length, IComparer`1 comparer) at System.Array.Sort[T](T[] array, Int32 index, Int32 length, IComparer`1 comparer) at System.Array.Sort[T](T[] array) at Assignment5.Taxpayer.Main(String[] args) in Program.cs:line 150 Notice the 0s at the end of the line that should be the tax amount??? Here is the code: using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace taxes { class Rates { // Create a class named rates that has the following data members: private int incLimit; private double lowTaxRate; private double highTaxRate; // use read-only accessor public int IncomeLimit { get { return incLimit; } } public double LowTaxRate { get { return lowTaxRate; } } public double HighTaxRate { get { return highTaxRate; } } //A class constructor that assigns default values public Rates() { int limit = 30000; double lowRate = .15; double highRate = .28; incLimit = limit; lowTaxRate = lowRate; highTaxRate = highRate; } //A class constructor that takes three parameters to assign input values for limit, low rate and high rate. public Rates(int limit, double lowRate, double highRate) { } // A CalculateTax method that takes an income parameter and computes the tax as follows: public int CalculateTax(int income) { int limit = 0; double lowRate = 0; double highRate = 0; int taxOwed = 0; // If income is less than the limit then return the tax as income times low rate. if (income < limit) taxOwed = Convert.ToInt32(income * lowRate); // If income is greater than or equal to the limit then return the tax as income times high rate. if (income >= limit) taxOwed = Convert.ToInt32(income * highRate); return taxOwed; } } //end class Rates // Create a class named Taxpayer that has the following data members: public class Taxpayer { //Use get and set accessors. string SSN { get; set; } int grossIncome { get; set; } // Use read-only accessor. public int taxOwed { get { return taxOwed; } } // The Taxpayer class should be set up so that its objects are comparable to each other based on tax owed. class taxpayer : IComparable { public int taxOwed { get; set; } public int income { get; set; } int IComparable.CompareTo(Object o) { int returnVal; taxpayer temp = (taxpayer)o; if (this.taxOwed > temp.taxOwed) returnVal = 1; else if (this.taxOwed < temp.taxOwed) returnVal = -1; else returnVal = 0; return returnVal; } // End IComparable.CompareTo } //end taxpayer IComparable class // **The tax should be calculated whenever the income is set. // The Taxpayer class should have a getRates class method that has the following. public static void GetRates() { // Local method data members for income limit, low rate and high rate. int incLimit = 0; double lowRate; double highRate; string userInput; // Prompt the user to enter a selection for either default settings or user input of settings. Console.Write("Would you like the default values (D) or would you like to enter the values (E)?: "); /* If the user selects default the default values you will instantiate a rates object using the default constructor * and set the Taxpayer class data member for tax equal to the value returned from calling the rates object CalculateTax method.*/ userInput = Convert.ToString(Console.ReadLine()); if (userInput == "D" || userInput == "d") { Rates rates = new Rates(); rates.CalculateTax(incLimit); } // end if /* If the user selects to enter the rates data then prompt the user to enter values for income limit, low rate and high rate, * instantiate a rates object using the three-argument constructor passing those three entries as the constructor arguments and * set the Taxpayer class data member for tax equal to the valuereturned from calling the rates object CalculateTax method. */ if (userInput == "E" || userInput == "e") { Console.Write("Please enter the income limit: "); incLimit = Convert.ToInt32(Console.ReadLine()); Console.Write("Please enter the low rate: "); lowRate = Convert.ToDouble(Console.ReadLine()); Console.Write("Please enter the high rate: "); highRate = Convert.ToDouble(Console.ReadLine()); Rates rates = new Rates(incLimit, lowRate, highRate); rates.CalculateTax(incLimit); } } static void Main(string[] args) { Taxpayer[] taxArray = new Taxpayer[5]; Rates taxRates = new Rates(); // Implement a for-loop that will prompt the user to enter the Social Security Number and gross income. for (int x = 0; x < taxArray.Length; ++x) { taxArray[x] = new Taxpayer(); Console.Write("Please enter the Social Security Number for taxpayer {0}: ", x + 1); taxArray[x].SSN = Console.ReadLine(); Console.Write("Please enter the gross income for taxpayer {0}: ", x + 1); taxArray[x].grossIncome = Convert.ToInt32(Console.ReadLine()); } Taxpayer.GetRates(); // Implement a for-loop that will display each object as formatted taxpayer SSN, income and calculated tax. for (int i = 0; i < taxArray.Length; ++i) { Console.WriteLine("Taxpayer # {0} SSN: {1}, Income is {2:c}, Tax is {3:c}", i + 1, taxArray[i].SSN, taxArray[i].grossIncome, taxRates.CalculateTax(taxArray[i].grossIncome)); } // end for // Implement a for-loop that will sort the five objects in order by the amount of tax owed Array.Sort(taxArray); Console.WriteLine("Sorted by tax owed"); for (int i = 0; i < taxArray.Length; ++i) { Console.WriteLine("Taxpayer # {0} SSN: {1}, Income is {2:c}, Tax is {3:c}", i + 1, taxArray[i].SSN, taxArray[i].grossIncome, taxRates.CalculateTax(taxArray[i].grossIncome)); } } //end main } // end Taxpayer class } //end Any clues as to why the dollar amount is coming up as 0 and why the sort is not working?

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  • Wikipedia A* pathfinding algorithm takes a lot of time

    - by Vee
    I've successfully implemented A* pathfinding in C# but it is very slow, and I don't understand why. I even tried not sorting the openNodes list but it's still the same. The map is 80x80, and there are 10-11 nodes. I took the pseudocode from here Wikipedia And this is my implementation: public static List<PGNode> Pathfind(PGMap mMap, PGNode mStart, PGNode mEnd) { mMap.ClearNodes(); mMap.GetTile(mStart.X, mStart.Y).Value = 0; mMap.GetTile(mEnd.X, mEnd.Y).Value = 0; List<PGNode> openNodes = new List<PGNode>(); List<PGNode> closedNodes = new List<PGNode>(); List<PGNode> solutionNodes = new List<PGNode>(); mStart.G = 0; mStart.H = GetManhattanHeuristic(mStart, mEnd); solutionNodes.Add(mStart); solutionNodes.Add(mEnd); openNodes.Add(mStart); // 1) Add the starting square (or node) to the open list. while (openNodes.Count > 0) // 2) Repeat the following: { openNodes.Sort((p1, p2) => p1.F.CompareTo(p2.F)); PGNode current = openNodes[0]; // a) We refer to this as the current square.) if (current == mEnd) { while (current != null) { solutionNodes.Add(current); current = current.Parent; } return solutionNodes; } openNodes.Remove(current); closedNodes.Add(current); // b) Switch it to the closed list. List<PGNode> neighborNodes = current.GetNeighborNodes(); double cost = 0; bool isCostBetter = false; for (int i = 0; i < neighborNodes.Count; i++) { PGNode neighbor = neighborNodes[i]; cost = current.G + 10; isCostBetter = false; if (neighbor.Passable == false || closedNodes.Contains(neighbor)) continue; // If it is not walkable or if it is on the closed list, ignore it. if (openNodes.Contains(neighbor) == false) { openNodes.Add(neighbor); // If it isn’t on the open list, add it to the open list. isCostBetter = true; } else if (cost < neighbor.G) { isCostBetter = true; } if (isCostBetter) { neighbor.Parent = current; // Make the current square the parent of this square. neighbor.G = cost; neighbor.H = GetManhattanHeuristic(current, neighbor); } } } return null; } Here's the heuristic I'm using: private static double GetManhattanHeuristic(PGNode mStart, PGNode mEnd) { return Math.Abs(mStart.X - mEnd.X) + Math.Abs(mStart.Y - mEnd.Y); } What am I doing wrong? It's an entire day I keep looking at the same code.

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  • How to use custom IComparer for SortedDictionary?

    - by Magnus Johansson
    I am having difficulties to use my custom IComparer for my SortedDictionary<. The goal is to put email addresses in a specific format ([email protected]) as the key, and sort by last name. When I do something like this: public class Program { public static void Main(string[] args) { SortedDictionary<string, string> list = new SortedDictionary<string, string>(new SortEmailComparer()); list.Add("[email protected]", "value1"); list.Add("[email protected]", "value2"); foreach (KeyValuePair<string, string> kvp in list) { Console.WriteLine(kvp.Key); } Console.ReadLine(); } } public class SortEmailComparer : IComparer<string> { public int Compare(string x, string y) { Regex regex = new Regex("\\b\\w*@\\b", RegexOptions.IgnoreCase | RegexOptions.CultureInvariant | RegexOptions.IgnorePatternWhitespace | RegexOptions.Compiled ); string xLastname = regex.Match(x).ToString().Trim('@'); string yLastname = regex.Match(y).ToString().Trim('@'); return xLastname.CompareTo(yLastname); } } I get this ArgumentException: An entry with the same key already exists. when adding the second item. I haven't worked with a custom IComparer for a SortedDictionary before, and I fail to see my error , what am I doing wrong?

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  • Entlib validation to syntax to accept only numeric month numbers?

    - by ElHaix
    I've got an enum defined as such: Private Enum AllowedMonthNumbers _1 _2 _3 _4 _5 _6 _7 _8 _9 _10 _11 _12 End Enum Then a property validator defined as: <TypeConversionValidator(GetType(Int32), MessageTemplate:="Card expiry month must be numeric.", Ruleset:="CreditCard")> _ <EnumConversionValidator(GetType(AllowedMonthNumbers), MessageTemplate:="Card expiry month must be between 1 and 12.", Ruleset:="CreditCard")> _ The validation expects "_#", as when I remove the TypeConversionValidator, it passes with setting the value to "_3" or any other number in the enum. What I need is for this to only accept b/t 1-12, and simply having numeric values in the enum won't work. Any tips? Thanks. UPDATE I replaced the EnumConversionValidator with a RangeValidator, and attempting to set the parameter to "1", but received the following error: <RangeValidator(1, RangeBoundaryType.Inclusive, 12, RangeBoundaryType.Inclusive, MessageTemplate:="..."> However that's now giving me the following error: System.Web.Services.Protocols.SoapException : System.Web.Services.Protocols.SoapException: Server was unable to process request. ---> System.ArgumentException: Object must be of type Int32. at System.Int32.CompareTo(Object value) at Microsoft.Practices.EnterpriseLibrary.Validation.Validators.RangeChecker`1.IsInRange(T target) at Microsoft.Practices.EnterpriseLibrary.Validation.Validators.RangeValidator`1.DoValidate(T objectToValidate, Object currentTarget, String key, ValidationResults validationResults) at Microsoft.Practices.EnterpriseLibrary.Validation.Validator`1.DoValidate(Object objectToValidate, Object currentTarget, String key, ValidationResults validationResults) at Microsoft.Practices.EnterpriseLibrary.Validation.Validators.AndCompositeValidator.DoValidate(Object objectToValidate, Object currentTarget, String key, ValidationResults validationResults) at Microsoft.Practices.EnterpriseLibrary.Validation.Validators.ValueAccessValidator.DoValidate(Object objectToValidate, Object currentTarget, String key, ValidationResults validationResults) at Microsoft.Practices.EnterpriseLibrary.Validation.Validators.AndCompositeValidator.DoValidate(Object objectToValidate, Object currentTarget, String key, ValidationResults validationResults) at Microsoft.Practices.EnterpriseLibrary.Validation.Validators.GenericValidatorWrapper`1.DoValidate(T objectToValidate, Object currentTarget, String key, ValidationResults validationResults) at Microsoft.Practices.EnterpriseLibrary.Validation.Validator`1.Validate(T target, ValidationResults validationResults) at Microsoft.Practices.EnterpriseLibrary.Validation.Validation.Validate[T](T target, String[] rulesets) at ....

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  • longest string in texts

    - by davit-datuashvili
    Ihave following code in Java: import java.util.*; public class longest{ public static void main(String[] args){ int t=0;int m=0;int token1, token2; String words[]=new String[10]; String word[]=new String[10]; String common[]=new String[10]; String text="saqartvelo gabrwyindeba da gadzlierdeba aucileblad "; String text1="saqartvelo gamtliandeba da gadzlierdeba aucileblad"; StringTokenizer st=new StringTokenizer(text); StringTokenizer st1=new StringTokenizer(text1); token1=st.countTokens(); token2=st1.countTokens(); while (st.hasMoreTokens()){ words[t]=st.nextToken(); t++; } while (st1.hasMoreTokens()){ word[m]=st1.nextToken(); m++; } for (int k=0;k<token1;k++){ for (int f=0;f<token2;f++){ if (words[f].compareTo(word[f])==0){ common[f]=words[f]; } } } while (i<common.length){ System.out.println(common[i]); i++; } } } I want that in common array put elements which i in both text or these words saqartvelo (georgia in english) da (and in english) gadzlierdeba (will be stronger) aucileblad (sure) and then between these words find string which has maximum length but it does not work more correctly it show me these words and also many null elements. How do I correct it?

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  • Java SortedMap to Scala TreeMap

    - by Dave
    I'm having trouble converting a java SortedMap into a scala TreeMap. The SortedMap comes from deserialization and needs to be converted into a scala structure before being used. Some background, for the curious, is that the serialized structure is written through XStream and on desializing I register a converter that says anything that can be assigned to SortedMap[Comparable[_],_] should be given to me. So my convert method gets called and is given an Object that I can safely cast because I know it's of type SortedMap[Comparable[_],_]. That's where it gets interesting. Here's some sample code that might help explain it. // a conversion from comparable to ordering scala> implicit def comparable2ordering[A <: Comparable[A]](x: A): Ordering[A] = new Ordering[A] { | def compare(x: A, y: A) = x.compareTo(y) | } comparable2ordering: [A <: java.lang.Comparable[A]](x: A)Ordering[A] // jm is how I see the map in the converter. Just as an object. I know the key // is of type Comparable[_] scala> val jm : Object = new java.util.TreeMap[Comparable[_], String]() jm: java.lang.Object = {} // It's safe to cast as the converter only gets called for SortedMap[Comparable[_],_] scala> val b = jm.asInstanceOf[java.util.SortedMap[Comparable[_],_]] b: java.util.SortedMap[java.lang.Comparable[_], _] = {} // Now I want to convert this to a tree map scala> collection.immutable.TreeMap() ++ (for(k <- b.keySet) yield { (k, b.get(k)) }) <console>:15: error: diverging implicit expansion for type Ordering[A] starting with method Tuple9 in object Ordering collection.immutable.TreeMap() ++ (for(k <- b.keySet) yield { (k, b.get(k)) })

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  • List.Sort in C#: comparer being called with null object

    - by cbp
    I am getting strange behaviour using the built-in C# List.Sort function with a custom comparer. For some reason it sometimes calls the comparer class's Compare method with a null object as one of the parameters. But if I check the list with the debugger there are no null objects in the collection. My comparer class looks like this: public class DelegateToComparer<T> : IComparer<T> { private readonly Func<T,T,int> _comparer; public int Compare(T x, T y) { return _comparer(x, y); } public DelegateToComparer(Func<T, T, int> comparer) { _comparer = comparer; } } This allows a delegate to be passed to the List.Sort method, like this: mylist.Sort(new DelegateToComparer<MyClass>( (x, y) => { return x.SomeProp.CompareTo(y.SomeProp); }); So the above delegate will throw a null reference exception for the x parameter, even though no elements of mylist are null. UPDATE: Yes I am absolutely sure that it is parameter x throwing the null reference exception! UPDATE: Instead of using the framework's List.Sort method, I tried a custom sort method (i.e. new BubbleSort().Sort(mylist)) and the problem went away. As I suspected, the List.Sort method passes null to the comparer for some reason.

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  • Implementing Java Priority Queue

    - by Kay
    public class PriorityQueue<T> { private PriorityNode<T> head, tail; private int numItems; public PriorityQueue(){ numItems = 0; head=null; tail=null; } public void add(int priority, T value){ PriorityNode<T> newNode = new PriorityNode<T>(priority,value); if(numItems == 0){ head = newNode; tail = newNode; } else{ head.setNext(newNode); head = newNode; } } } Where PriorityNode is defined as: public class PriorityNode<T> implements Comparable<T> { private T value; private PriorityNode<T> next; private int priority; public PriorityNode(int priority,T newValue){ value = newValue; next = null; priority = 0; } public PriorityNode(T newValue){ value = newValue; next = null; priority = 0; } public void setPriority(int priority){ this.priority = priority; } public int getPriority(){ return this.priority; } public T getValue(){ return value; } public PriorityNode<T> getNext(){ return next; } public void setNext(PriorityNode<T> nextNode){ this.next = nextNode; } public void setValue(T newValue){ value = newValue; } public int compareTo(int pri) { // TODO Auto-generated method stub if(this.priority<pri){ return -1; } else if(this.priority == pri){ return 0; } else{ return 1; } } } I'm having a lot of difficulty using the Comparator here and implementing a priority queue - please point me in the right direction.

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  • Why does the Java Collections Framework offer two different ways to sort?

    - by dvanaria
    If I have a list of elements I would like to sort, Java offers two ways to go about this. For example, lets say I have a list of Movie objects and I’d like to sort them by title. One way I could do this is by calling the one-argument version of the static java.util.Collections.sort( ) method with my movie list as the single argument. So I would call Collections.sort(myMovieList). In order for this to work, the Movie class would have to be declared to implement the java.lang.Comparable interface, and the required method compareTo( ) would have to be implemented inside this class. Another way to sort is by calling the two-argument version of the static java.util.Collections.sort( ) method with the movie list and a java.util.Comparator object as it’s arguments. I would call Collections.sort(myMovieList, titleComparator). In this case, the Movie class wouldn’t implement the Comparable interface. Instead, inside the main class that builds and maintains the movie list itself, I would create an inner class that implements the java.util.Comparator interface, and implement the one required method compare( ). Then I'd create an instance of this class and call the two-argument version of sort( ). The benefit of this second method is you can create an unlimited number of these inner class Comparators, so you can sort a list of objects in different ways. In the example above, you could have another Comparator to sort by the year a movie was made, for example. My question is, why bother to learn both ways to sort in Java, when the two-argument version of Collections.sort( ) does everything the first one-argument version does, but with the added benefit of being able to sort the list’s elements based on several different criteria? It would be one less thing to have to keep in your mind while coding. You’d have one basic mechanism of sorting lists in Java to know.

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  • Java generic Comparable where subclasses can't compare to eachother

    - by dege
    public abstract class MyAbs implements Comparable<MyAbs> This would work but then I would be able to compare class A and B with each other if they both extend MyAbs. What I want to accomplish however is the exact opposite. So does anyone know a way to get the generic type to be the own class? Seemed like such a simple thing at first... Edit: To explain it a little further with an example. Say you have an abstract class animals, then you extend it with Dogs and ants. I wouldn't want to compare ants with Dogs but I however would want to compare one dog with another. The dog might have a variable saying what color it is and that is what I want to use in the compareTo method. However when it comes to ants I would rather want to compare ant's size than their color. Hope that clears it up. Could possibly be a design flaw however.

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  • Unable to change background colour for JOptionPane

    - by Sunil Kumar Sahoo
    Hi I have created sample progeam which will give same look and feel of a confirm dialog and set the background colour as red. But I donot know what is the problem that my background colour of option is displayed as the default colour but not red. also i need same look and feel of confirm dialog across all platforms. Here is the code that I have written. please help me to solve the issue public class JOptionPaneBackground { public static void main(String[] args) throws Exception { // UIManager.setLookAndFeel(UIManager.getCrossPlatformLookAndFeelClassName()); UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName()); UIDefaults uiDefaults = UIManager.getLookAndFeelDefaults(); List<Object> keys = new ArrayList<Object>(uiDefaults.keySet()); Collections.sort(keys, new Comparator<Object>() { public int compare(Object o1, Object o2) { return (o1.toString()).compareTo(o2.toString()); } }); for (Object key : keys) { System.out.println(String.format("%-40s = %s", key, uiDefaults.get(key))); } UIManager.put("OptionPane.background", Color.red); UIManager.put("Panel.background", Color.red); JOptionPane.showConfirmDialog(null, "Hello World!"); } }

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  • Utility of List<T>.Sort() versus List<T>.OrderBy() for a member of a custom container class

    - by ccomet
    I've found myself running back through some old 3.5 framework legacy code, and found some points where there are a whole bunch of lists and dictionaries that must be updated in a synchronized fashion. I've determined that I can make this process infinitely easier to both utilize and understand by converging these into custom container classes of new custom classes. There are some points, however, where I came to concerns with organizing the contents of these new container classes by a specific inner property. For example, sorting by the ID number property of one class. As the container classes are primarily based around a generic List object, my first instinct was to write the inner classes with IComparable, and write the CompareTo method that compares the properties. This way, I can just call items.Sort() when I want to invoke the sorting. However, I've been thinking instead about using items = items.OrderBy(Func) instead. This way it is more flexible if I need to sort by any other property. Readability is better as well, since the property used for sorting will be listed in-line with the sort call rather than having to look up the IComparable code. The overall implementation feels cleaner as a result. I don't care for premature or micro optimization, but I like consistency. I find it best to stick with one kind of implementation for as many cases as it is appropriate, and use different implementations where it is necessary. Is it worth it to convert my code to use the LINQ OrderBy instead of using List.Sort? Is it a better practice to stick with the IComparable implementation for these custom containers? Are there any significant mechanical advantages offered by either path that I should be weighing the decision on? Or is their end-functionality equivalent to the point that it just becomes coder's preference?

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  • Recursive QuickSort suffering a StackOverflowException -- Need fresh eyes

    - by jon
    I am working on a Recursive QuickSort method implementation in a GenericList Class. I will have a second method that accepts a compareDelegate to compare different types, but for development purposes I'm sorting a GenericList<int I am recieving stackoverflow areas in different places depending on the list size. I've been staring at and tracing through this code for hours and probably just need a fresh pair of (more experienced)eyes. Definitely wanting to learn why it is broken, not just how to fix it. public void QuickSort() { int i, j, lowPos, highPos, pivot; GenericList<T> leftList = new GenericList<T>(); GenericList<T> rightList = new GenericList<T>(); GenericList<T> tempList = new GenericList<T>(); lowPos = 1; highPos = this.Count; if (lowPos < highPos) { pivot = (lowPos + highPos) / 2; for (i = 1; i <= highPos; i++) { if (this[i].CompareTo(this[pivot]) <= 0) leftList.Add(this[i]); else rightList.Add(this[i]); } leftList.QuickSort(); rightList.QuickSort(); for(i=1;i<=leftList.Count;i++) tempList.Add(leftList[i]); for(i=1;i<=rightList.Count;i++) tempList.Add(rightList[i]); this.items = tempList.items; this.count = tempList.count; } }

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