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  • Questions related to writing your own file downloader using multiple threads java

    - by Shekhar
    Hello In my current company, i am doing a PoC on how we can write a file downloader utility. We have to use socket programming(TCP/IP) for downloading the files. One of the requirements of the client is that a file(which will be large in size) should be transfered in chunks for example if we have a file of 5Mb size then we can have 5 threads which transfer 1 Mb each. I have written a small application which downloads a file. You can download the eclipe project from http://www.fileflyer.com/view/QM1JSC0 A brief explanation of my classes FileSender.java This class provides the bytes of file. It has a method called sendBytesOfFile(long start,long end, long sequenceNo) which gives the number of bytes. import java.io.File; import java.io.IOException; import java.util.zip.CRC32; import org.apache.commons.io.FileUtils; public class FileSender { private static final String FILE_NAME = "C:\\shared\\test.pdf"; public ByteArrayWrapper sendBytesOfFile(long start,long end, long sequenceNo){ try { File file = new File(FILE_NAME); byte[] fileBytes = FileUtils.readFileToByteArray(file); System.out.println("Size of file is " +fileBytes.length); System.out.println(); System.out.println("Start "+start +" end "+end); byte[] bytes = getByteArray(fileBytes, start, end); ByteArrayWrapper wrapper = new ByteArrayWrapper(bytes, sequenceNo); return wrapper; } catch (IOException e) { throw new RuntimeException(e); } } private byte[] getByteArray(byte[] bytes, long start, long end){ long arrayLength = end-start; System.out.println("Start : "+start +" end : "+end + " Arraylength : "+arrayLength +" length of source array : "+bytes.length); byte[] arr = new byte[(int)arrayLength]; for(int i = (int)start, j =0; i < end;i++,j++){ arr[j] = bytes[i]; } return arr; } public static long fileSize(){ File file = new File(FILE_NAME); return file.length(); } } Second Class is FileReceiver.java - This class receives the file. Small Explanation what this file does This class finds the size of the file to be fetched from Sender Depending upon the size of the file it finds the start and end position till the bytes needs to be read. It starts n number of threads giving each thread start,end, sequence number and a list which all the threads share. Each thread reads the number of bytes and creates a ByteArrayWrapper. ByteArrayWrapper objects are added to the list Then i have while loop which basically make sure that all threads have done their work finally it sorts the list based on the sequence number. then the bytes are joined, and a complete byte array is formed which is converted to a file. Code of File Receiver package com.filedownloader; import java.io.File; import java.io.IOException; import java.util.ArrayList; import java.util.Collections; import java.util.Comparator; import java.util.List; import java.util.zip.CRC32; import org.apache.commons.io.FileUtils; public class FileReceiver { public static void main(String[] args) { FileReceiver receiver = new FileReceiver(); receiver.receiveFile(); } public void receiveFile(){ long startTime = System.currentTimeMillis(); long numberOfThreads = 10; long filesize = FileSender.fileSize(); System.out.println("File size received "+filesize); long start = filesize/numberOfThreads; List<ByteArrayWrapper> list = new ArrayList<ByteArrayWrapper>(); for(long threadCount =0; threadCount<numberOfThreads ;threadCount++){ FileDownloaderTask task = new FileDownloaderTask(threadCount*start,(threadCount+1)*start,threadCount,list); new Thread(task).start(); } while(list.size() != numberOfThreads){ // this is done so that all the threads should complete their work before processing further. //System.out.println("Waiting for threads to complete. List size "+list.size()); } if(list.size() == numberOfThreads){ System.out.println("All bytes received "+list); Collections.sort(list, new Comparator<ByteArrayWrapper>() { @Override public int compare(ByteArrayWrapper o1, ByteArrayWrapper o2) { long sequence1 = o1.getSequence(); long sequence2 = o2.getSequence(); if(sequence1 < sequence2){ return -1; }else if(sequence1 > sequence2){ return 1; } else{ return 0; } } }); byte[] totalBytes = list.get(0).getBytes(); byte[] firstArr = null; byte[] secondArr = null; for(int i = 1;i<list.size();i++){ firstArr = totalBytes; secondArr = list.get(i).getBytes(); totalBytes = concat(firstArr, secondArr); } System.out.println(totalBytes.length); convertToFile(totalBytes,"c:\\tmp\\test.pdf"); long endTime = System.currentTimeMillis(); System.out.println("Total time taken with "+numberOfThreads +" threads is "+(endTime-startTime)+" ms" ); } } private byte[] concat(byte[] A, byte[] B) { byte[] C= new byte[A.length+B.length]; System.arraycopy(A, 0, C, 0, A.length); System.arraycopy(B, 0, C, A.length, B.length); return C; } private void convertToFile(byte[] totalBytes,String name) { try { FileUtils.writeByteArrayToFile(new File(name), totalBytes); } catch (IOException e) { throw new RuntimeException(e); } } } Code of ByteArrayWrapper package com.filedownloader; import java.io.Serializable; public class ByteArrayWrapper implements Serializable{ private static final long serialVersionUID = 3499562855188457886L; private byte[] bytes; private long sequence; public ByteArrayWrapper(byte[] bytes, long sequenceNo) { this.bytes = bytes; this.sequence = sequenceNo; } public byte[] getBytes() { return bytes; } public long getSequence() { return sequence; } } Code of FileDownloaderTask import java.util.List; public class FileDownloaderTask implements Runnable { private List<ByteArrayWrapper> list; private long start; private long end; private long sequenceNo; public FileDownloaderTask(long start,long end,long sequenceNo,List<ByteArrayWrapper> list) { this.list = list; this.start = start; this.end = end; this.sequenceNo = sequenceNo; } @Override public void run() { ByteArrayWrapper wrapper = new FileSender().sendBytesOfFile(start, end, sequenceNo); list.add(wrapper); } } Questions related to this code 1) Does file downloading becomes fast when multiple threads is used? In this code i am not able to see the benefit. 2) How should i decide how many threads should i create ? 3) Are their any opensource libraries which does that 4) The file which file receiver receives is valid and not corrupted but checksum (i used FileUtils of common-io) does not match. Whats the problem? 5) This code gives out of memory when used with large file(above 100 Mb) i.e. because byte array which is created. How can i avoid? I know this is a very bad code but i have to write this in one day -:). Please suggest any other good way to do this? Thanks Shekhar

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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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  • Implementing union of Set using basic java array

    - by lupindeterd
    Note: This is an assignment. Hi, Continuing with my Set implementation using Java basic array, I'm now struggling with the 3 to last function namely the union. import java.io.*; class Set { private int numberOfElements = 0; private String[] setElements = new String[5]; private int maxNumberOfElements = 5; // constructor for our Set class public Set(int numberOfE, int setE, int maxNumberOfE) { int numberOfElements = numberOfE; String[] setElements = new String[setE]; int maxNumberOfElements = maxNumberOfE; } // Helper method to shorten/remove element of array since we're using basic array instead of ArrayList or HashSet from collection interface :( static String[] removeAt(int k, String[] arr) { final int L = arr.length; String[] ret = new String[L - 1]; System.arraycopy(arr, 0, ret, 0, k); System.arraycopy(arr, k + 1, ret, k, L - k - 1); return ret; } int findElement(String element) { int retval = 0; for ( int i = 0; i < setElements.length; i++) { if ( setElements[i] != null && setElements[i].equals(element) ) { return retval = i; } retval = -1; } return retval; } void add(String newValue) { int elem = findElement(newValue); if( numberOfElements < maxNumberOfElements && elem == -1 ) { setElements[numberOfElements] = newValue; numberOfElements++; } } int getLength() { if ( setElements != null ) { return setElements.length; } else { return 0; } } String[] emptySet() { setElements = new String[0]; return setElements; } Boolean isFull() { Boolean True = new Boolean(true); Boolean False = new Boolean(false); if ( setElements.length == maxNumberOfElements ){ return True; } else { return False; } } Boolean isEmpty() { Boolean True = new Boolean(true); Boolean False = new Boolean(false); if ( setElements.length == 0 ) { return True; } else { return False; } } void remove(String newValue) { for ( int i = 0; i < setElements.length; i++) { if ( setElements[i].equals(newValue) ) { setElements = removeAt(i,setElements); } } } int isAMember(String element) { int retval = -1; for ( int i = 0; i < setElements.length; i++ ) { if (setElements[i] != null && setElements[i].equals(element)) { return retval = i; } } return retval; } void printSet() { for ( int i = 0; i < setElements.length; i++) { System.out.println("Member elements on index: "+ i +" " + setElements[i]); } } String[] getMember() { String[] tempArray = new String[setElements.length]; for ( int i = 0; i < setElements.length; i++) { if(setElements[i] != null) { tempArray[i] = setElements[i]; } } return tempArray; } Set union(Set x, Set y) { String[] newtemparray = new String[x.getLength]; newtemparray = x.getMember; return x; } } // This is the SetDemo class that will make use of our Set class class SetDemo { public static void main(String[] args) { //get input from keyboard BufferedReader keyboard; InputStreamReader reader; String temp = ""; reader = new InputStreamReader(System.in); keyboard = new BufferedReader(reader); try { System.out.println("Enter string element to be added" ); temp = keyboard.readLine( ); System.out.println("You entered " + temp ); } catch (IOException IOerr) { System.out.println("There was an error during input"); } /* ************************************************************************** * Test cases for our new created Set class. * ************************************************************************** */ Set setA = new Set(1,10,10); setA.add(temp); setA.add("b"); setA.add("b"); setA.add("hello"); setA.add("world"); setA.add("six"); setA.add("seven"); setA.add("b"); int size = setA.getLength(); System.out.println("Set size is: " + size ); Boolean isempty = setA.isEmpty(); System.out.println("Set is empty? " + isempty ); int ismember = setA.isAMember("sixb"); System.out.println("Element six is member of setA? " + ismember ); Boolean output = setA.isFull(); System.out.println("Set is full? " + output ); setA.printSet(); int index = setA.findElement("world"); System.out.println("Element b located on index: " + index ); setA.remove("b"); setA.emptySet(); int resize = setA.getLength(); System.out.println("Set size is: " + resize ); setA.printSet(); Set setB = new Set(0,10,10); Set SetA = setA.union(setB,setA); } } Ok the method in question will be the implementation of union. As such this: Set union(Set x, Set y) { String[] newtemparray = new String[x.getLength]; newtemparray = x.getMember; return x; } I got this error: symbol : variable getLength location: class Set String[] newtemparray = new String[x.getLength]; ^ d:\javaprojects\Set.java:122: cannot find symbol symbol : variable getMember location: class Set newtemparray = x.getMember; ^ 2 errors My approach for union would be: *) create temporary array of string with size of the object x length. *) store object x members to temporary array by looping the object and calling the getMember *) loop object y members and check if element exist against temporary array. *) discard if it exist/add if it is not there *) return obj x with the union array. thanks, lupin

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  • Sorting and Re-arranging List of HashMaps

    - by HonorGod
    I have a List which is straight forward representation of a database table. I am trying to sort and apply some magic after the data is loaded into List of HashMaps. In my case this is the only hard and fast way of doing it becoz I have a rules engine that actually updates the values in the HashMap after several computations. Here is a sample data representation of the HashMap (List of HashMap) - {fromDate=Wed Mar 17 10:54:12 EDT 2010, eventId=21, toDate=Tue Mar 23 10:54:12 EDT 2010, actionId=1234} {fromDate=Wed Mar 17 10:54:12 EDT 2010, eventId=11, toDate=Wed Mar 17 10:54:12 EDT 2010, actionId=456} {fromDate=Sat Mar 20 10:54:12 EDT 2010, eventId=20, toDate=Thu Apr 01 10:54:12 EDT 2010, actionId=1234} {fromDate=Wed Mar 24 10:54:12 EDT 2010, eventId=22, toDate=Sat Mar 27 10:54:12 EDT 2010, actionId=1234} {fromDate=Wed Mar 17 10:54:12 EDT 2010, eventId=11, toDate=Fri Mar 26 10:54:12 EDT 2010, actionId=1234} {fromDate=Sat Mar 20 10:54:12 EDT 2010, eventId=11, toDate=Wed Mar 31 10:54:12 EDT 2010, actionId=1234} {fromDate=Mon Mar 15 10:54:12 EDT 2010, eventId=12, toDate=Wed Mar 17 10:54:12 EDT 2010, actionId=567} I am trying to achieve couple of things - 1) Sort the list by actionId and eventId after which the data would look like - {fromDate=Wed Mar 17 10:54:12 EDT 2010, eventId=11, toDate=Wed Mar 17 10:54:12 EDT 2010, actionId=456} {fromDate=Mon Mar 15 10:54:12 EDT 2010, eventId=12, toDate=Wed Mar 17 10:54:12 EDT 2010, actionId=567} {fromDate=Wed Mar 24 10:54:12 EDT 2010, eventId=22, toDate=Sat Mar 27 10:54:12 EDT 2010, actionId=1234} {fromDate=Wed Mar 17 10:54:12 EDT 2010, eventId=21, toDate=Tue Mar 23 10:54:12 EDT 2010, actionId=1234} {fromDate=Sat Mar 20 10:54:12 EDT 2010, eventId=20, toDate=Thu Apr 01 10:54:12 EDT 2010, actionId=1234} {fromDate=Wed Mar 17 10:54:12 EDT 2010, eventId=11, toDate=Fri Mar 26 10:54:12 EDT 2010, actionId=1234} {fromDate=Sat Mar 20 10:54:12 EDT 2010, eventId=11, toDate=Wed Mar 31 10:54:12 EDT 2010, actionId=1234} 2) If we group the above list by actionId they would be resolved into 3 groups - actionId=1234, actionId=567 and actionId=456. Now here is my question - For each group having the same eventId, I need to update the records so that they have wider fromDate to toDate. Meaning, if you consider the last two rows they have same actionId = 1234 and same eventId = 11. Now we can to pick the least fromDate from those 2 records which is Wed Mar 17 10:54:12 and farther toDate which is Wed Mar 31 10:54:12 and update those 2 record's fromDate and toDate to Wed Mar 17 10:54:12 and Wed Mar 31 10:54:12 respectively. Any ideas? PS: I already have some pseudo code to start with. import java.util.ArrayList; import java.util.Calendar; import java.util.Collections; import java.util.Comparator; import java.util.Date; import java.util.HashMap; import java.util.List; import org.apache.commons.lang.builder.CompareToBuilder; public class Tester { boolean ascending = true ; boolean sortInstrumentIdAsc = true ; boolean sortEventTypeIdAsc = true ; public static void main(String args[]) { Tester tester = new Tester() ; tester.printValues() ; } public void printValues () { List<HashMap<String,Object>> list = new ArrayList<HashMap<String,Object>>() ; HashMap<String,Object> map = new HashMap<String,Object>(); map.put("actionId", new Integer(1234)) ; map.put("eventId", new Integer(21)) ; map.put("fromDate", getDate(1) ) ; map.put("toDate", getDate(7) ) ; list.add(map); map = new HashMap<String,Object>(); map.put("actionId", new Integer(456)) ; map.put("eventId", new Integer(11)) ; map.put("fromDate", getDate(1)) ; map.put("toDate", getDate(1) ) ; list.add(map); map = new HashMap<String,Object>(); map.put("actionId", new Integer(1234)) ; map.put("eventId", new Integer(20)) ; map.put("fromDate", getDate(4) ) ; map.put("toDate", getDate(16) ) ; list.add(map); map = new HashMap<String,Object>(); map.put("actionId", new Integer(1234)) ; map.put("eventId", new Integer(22)) ; map.put("fromDate",getDate(8) ) ; map.put("toDate", getDate(11)) ; list.add(map); map = new HashMap<String,Object>(); map.put("actionId", new Integer(1234)) ; map.put("eventId", new Integer(11)) ; map.put("fromDate",getDate(1) ) ; map.put("toDate", getDate(10) ) ; list.add(map); map = new HashMap<String,Object>(); map.put("actionId", new Integer(1234)) ; map.put("eventId", new Integer(11)) ; map.put("fromDate",getDate(4) ) ; map.put("toDate", getDate(15) ) ; list.add(map); map = new HashMap<String,Object>(); map.put("actionId", new Integer(567)) ; map.put("eventId", new Integer(12)) ; map.put("fromDate", getDate(-1) ) ; map.put("toDate",getDate(1)) ; list.add(map); System.out.println("\n Before Sorting \n "); for(int j = 0 ; j < list.size() ; j ++ ) System.out.println(list.get(j)); Collections.sort ( list , new HashMapComparator2 () ) ; System.out.println("\n After Sorting \n "); for(int j = 0 ; j < list.size() ; j ++ ) System.out.println(list.get(j)); } public static Date getDate(int days) { Calendar cal = Calendar.getInstance(); cal.setTime(new Date()); cal.add(Calendar.DATE, days); return cal.getTime() ; } public class HashMapComparator2 implements Comparator { public int compare ( Object object1 , Object object2 ) { if ( ascending == true ) { return new CompareToBuilder() .append(( ( HashMap ) object1 ).get ( "actionId" ), ( ( HashMap ) object2 ).get ( "actionId" )) .append(( ( HashMap ) object2 ).get ( "eventId" ), ( ( HashMap ) object1 ).get ( "eventId" )) .toComparison(); } else { return new CompareToBuilder() .append(( ( HashMap ) object2 ).get ( "actionId" ), ( ( HashMap ) object1 ).get ( "actionId" )) .append(( ( HashMap ) object2 ).get ( "eventId" ), ( ( HashMap ) object1 ).get ( "eventId" )) .toComparison(); } } } }

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  • NullPointerException, Collections not storing data?

    - by Elliott
    Hi there, I posted this question earlier but not with the code in its entirety. The coe below also calls to other classes Background and Hydro which I have included at the bottom. I have a Nullpointerexception at the line indicate by asterisks. Which would suggest to me that the Collections are not storing data properly. Although when I check their size they seem correct. Thanks in advance. PS: If anyone would like to give me advice on how best to format my code to make it readable, it would be appreciated. Elliott package exam0607; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.net.URL; import java.util.Collection; import java.util.Scanner; import java.util.Vector; import exam0607.Hydro; import exam0607.Background;// this may not be necessary???? FIND OUT public class HydroAnalysis { public static void main(String[] args) { Collection hydroList = null; Collection backList = null; try{hydroList = readHydro("http://www.hep.ucl.ac.uk/undergrad/3459/exam_data/2006-07/final/hd_data.dat");} catch (IOException e){ e.getMessage();} try{backList = readBackground("http://www.hep.ucl.ac.uk/undergrad/3459/exam_data/2006-07/final/hd_bgd.dat"); //System.out.println(backList.size()); } catch (IOException e){ e.getMessage();} for(int i =0; i <=14; i++ ){ String nameroot = "HJK"; String middle = Integer.toString(i); String hydroName = nameroot + middle + "X"; System.out.println(hydroName); ALGO_1(hydroName, backList, hydroList); } } public static Collection readHydro(String url) throws IOException { URL u = new URL(url); InputStream is = u.openStream(); InputStreamReader isr = new InputStreamReader(is); BufferedReader b = new BufferedReader(isr); String line =""; Collection data = new Vector(); while((line = b.readLine())!= null){ Scanner s = new Scanner(line); String name = s.next(); System.out.println(name); double starttime = Double.parseDouble(s.next()); System.out.println(+starttime); double increment = Double.parseDouble(s.next()); System.out.println(+increment); double p = 0; double nterms = 0; while(s.hasNextDouble()){ p = Double.parseDouble(s.next()); System.out.println(+p); nterms++; System.out.println(+nterms); } Hydro SAMP = new Hydro(name, starttime, increment, p); data.add(SAMP); } return data; } public static Collection readBackground(String url) throws IOException { URL u = new URL(url); InputStream is = u.openStream(); InputStreamReader isr = new InputStreamReader(is); BufferedReader b = new BufferedReader(isr); String line =""; Vector data = new Vector(); while((line = b.readLine())!= null){ Scanner s = new Scanner(line); String name = s.next(); //System.out.println(name); double starttime = Double.parseDouble(s.next()); //System.out.println(starttime); double increment = Double.parseDouble(s.next()); //System.out.println(increment); double sum = 0; double p = 0; double nterms = 0; while((s.hasNextDouble())){ p = Double.parseDouble(s.next()); //System.out.println(p); nterms++; sum += p; } double pbmean = sum/nterms; Background SAMP = new Background(name, starttime, increment, pbmean); //System.out.println(SAMP); data.add(SAMP); } return data; } public static void ALGO_1(String hydroName, Collection backgs, Collection hydros){ //double aMin = Double.POSITIVE_INFINITY; //double sum = 0; double intensity = 0; double numberPN_SIG = 0; double POSITIVE_PN_SIG =0; //int numberOfRays = 0; for(Hydro hd: hydros){ System.out.println(hd.H_NAME); for(Background back : backgs){ System.out.println(back.H_NAME); if(back.H_NAME.equals(hydroName)){//ERROR HERE double PN_SIG = Math.max(0.0, hd.PN - back.PBMEAN); numberPN_SIG ++; if(PN_SIG 0){ intensity += PN_SIG; POSITIVE_PN_SIG ++; } } } double positive_fraction = POSITIVE_PN_SIG/numberPN_SIG; if(positive_fraction < 0.5){ System.out.println( hydroName + "is faulty" ); } else{System.out.println(hydroName + "is not faulty");} System.out.println(hydroName + "has instensity" + intensity); } } } THE BACKGROUND CLASS package exam0607; public class Background { String H_NAME; double T_START; double DT; double PBMEAN; public Background(String name, double starttime, double increment, double pbmean) { name = H_NAME; starttime = T_START; increment = DT; pbmean = PBMEAN; }} AND THE HYDRO CLASS public class Hydro { String H_NAME; double T_START; double DT; double PN; public double n; public Hydro(String name, double starttime, double increment, double p) { name = H_NAME; starttime = T_START; increment = DT; p = PN; } }

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  • Suggestions for duplicate file finder algorithm (using C)

    - by Andrei Ciobanu
    Hello, I wanted to write a program that test if two files are duplicates (have exactly the same content). First I test if the files have the same sizes, and if they have i start to compare their contents. My first idea, was to "split" the files into fixed size blocks, then start a thread for every block, fseek to startup character of every block and continue the comparisons in parallel. When a comparison from a thread fails, the other working threads are canceled, and the program exits out of the thread spawning loop. The code looks like this: dupf.h #ifndef __NM__DUPF__H__ #define __NM__DUPF__H__ #define NUM_THREADS 15 #define BLOCK_SIZE 8192 /* Thread argument structure */ struct thread_arg_s { const char *name_f1; /* First file name */ const char *name_f2; /* Second file name */ int cursor; /* Where to seek in the file */ }; typedef struct thread_arg_s thread_arg; /** * 'arg' is of type thread_arg. * Checks if the specified file blocks are * duplicates. */ void *check_block_dup(void *arg); /** * Checks if two files are duplicates */ int check_dup(const char *name_f1, const char *name_f2); /** * Returns a valid pointer to a file. * If the file (given by the path/name 'fname') cannot be opened * in 'mode', the program is interrupted an error message is shown. **/ FILE *safe_fopen(const char *name, const char *mode); #endif dupf.c #include <errno.h> #include <pthread.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/types.h> #include <sys/stat.h> #include <unistd.h> #include "dupf.h" FILE *safe_fopen(const char *fname, const char *mode) { FILE *f = NULL; f = fopen(fname, mode); if (f == NULL) { char emsg[255]; sprintf(emsg, "FOPEN() %s\t", fname); perror(emsg); exit(-1); } return (f); } void *check_block_dup(void *arg) { const char *name_f1 = NULL, *name_f2 = NULL; /* File names */ FILE *f1 = NULL, *f2 = NULL; /* Streams */ int cursor = 0; /* Reading cursor */ char buff_f1[BLOCK_SIZE], buff_f2[BLOCK_SIZE]; /* Character buffers */ int rchars_1, rchars_2; /* Readed characters */ /* Initializing variables from 'arg' */ name_f1 = ((thread_arg*)arg)->name_f1; name_f2 = ((thread_arg*)arg)->name_f2; cursor = ((thread_arg*)arg)->cursor; /* Opening files */ f1 = safe_fopen(name_f1, "r"); f2 = safe_fopen(name_f2, "r"); /* Setup cursor in files */ fseek(f1, cursor, SEEK_SET); fseek(f2, cursor, SEEK_SET); /* Initialize buffers */ rchars_1 = fread(buff_f1, 1, BLOCK_SIZE, f1); rchars_2 = fread(buff_f2, 1, BLOCK_SIZE, f2); if (rchars_1 != rchars_2) { /* fread failed to read the same portion. * program cannot continue */ perror("ERROR WHEN READING BLOCK"); exit(-1); } while (rchars_1-->0) { if (buff_f1[rchars_1] != buff_f2[rchars_1]) { /* Different characters */ fclose(f1); fclose(f2); pthread_exit("notdup"); } } /* Close streams */ fclose(f1); fclose(f2); pthread_exit("dup"); } int check_dup(const char *name_f1, const char *name_f2) { int num_blocks = 0; /* Number of 'blocks' to check */ int num_tsp = 0; /* Number of threads spawns */ int tsp_iter = 0; /* Iterator for threads spawns */ pthread_t *tsp_threads = NULL; thread_arg *tsp_threads_args = NULL; int tsp_threads_iter = 0; int thread_c_res = 0; /* Thread creation result */ int thread_j_res = 0; /* Thread join res */ int loop_res = 0; /* Function result */ int cursor; struct stat buf_f1; struct stat buf_f2; if (name_f1 == NULL || name_f2 == NULL) { /* Invalid input parameters */ perror("INVALID FNAMES\t"); return (-1); } if (stat(name_f1, &buf_f1) != 0 || stat(name_f2, &buf_f2) != 0) { /* Stat fails */ char emsg[255]; sprintf(emsg, "STAT() ERROR: %s %s\t", name_f1, name_f2); perror(emsg); return (-1); } if (buf_f1.st_size != buf_f2.st_size) { /* File have different sizes */ return (1); } /* Files have the same size, function exec. is continued */ num_blocks = (buf_f1.st_size / BLOCK_SIZE) + 1; num_tsp = (num_blocks / NUM_THREADS) + 1; cursor = 0; for (tsp_iter = 0; tsp_iter < num_tsp; tsp_iter++) { loop_res = 0; /* Create threads array for this spawn */ tsp_threads = malloc(NUM_THREADS * sizeof(*tsp_threads)); if (tsp_threads == NULL) { perror("TSP_THREADS ALLOC FAILURE\t"); return (-1); } /* Create arguments for every thread in the current spawn */ tsp_threads_args = malloc(NUM_THREADS * sizeof(*tsp_threads_args)); if (tsp_threads_args == NULL) { perror("TSP THREADS ARGS ALLOCA FAILURE\t"); return (-1); } /* Initialize arguments and create threads */ for (tsp_threads_iter = 0; tsp_threads_iter < NUM_THREADS; tsp_threads_iter++) { if (cursor >= buf_f1.st_size) { break; } tsp_threads_args[tsp_threads_iter].name_f1 = name_f1; tsp_threads_args[tsp_threads_iter].name_f2 = name_f2; tsp_threads_args[tsp_threads_iter].cursor = cursor; thread_c_res = pthread_create( &tsp_threads[tsp_threads_iter], NULL, check_block_dup, (void*)&tsp_threads_args[tsp_threads_iter]); if (thread_c_res != 0) { perror("THREAD CREATION FAILURE"); return (-1); } cursor+=BLOCK_SIZE; } /* Join last threads and get their status */ while (tsp_threads_iter-->0) { void *thread_res = NULL; thread_j_res = pthread_join(tsp_threads[tsp_threads_iter], &thread_res); if (thread_j_res != 0) { perror("THREAD JOIN FAILURE"); return (-1); } if (strcmp((char*)thread_res, "notdup")==0) { loop_res++; /* Closing other threads and exiting by condition * from loop. */ while (tsp_threads_iter-->0) { pthread_cancel(tsp_threads[tsp_threads_iter]); } } } free(tsp_threads); free(tsp_threads_args); if (loop_res > 0) { break; } } return (loop_res > 0) ? 1 : 0; } The function works fine (at least for what I've tested). Still, some guys from #C (freenode) suggested that the solution is overly complicated, and it may perform poorly because of parallel reading on hddisk. What I want to know: Is the threaded approach flawed by default ? Is fseek() so slow ? Is there a way to somehow map the files to memory and then compare them ?

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  • Customized listfield with image displaying from a url

    - by arunabha
    I am displaying a customized list field with text on the right side and image on the left side.The image comes from a URL dynamically.Initially i am placing a blank image on the left of the list field,then call URLBitmapField class's setURL method,which actually does the processing and places the processed image on top of the blank image.The image gets displayed on the list field,but to see that processed image i need to press any key or click on the list field items.I want the processed image to be displayed automatically in the list field after the processing.Can anyone tell me where i am getting wrong? import java.util.Vector; import net.rim.device.api.system.Bitmap; import net.rim.device.api.system.Display; import net.rim.device.api.ui.ContextMenu; import net.rim.device.api.ui.DrawStyle; import net.rim.device.api.ui.Field; import net.rim.device.api.ui.Font; import net.rim.device.api.ui.Graphics; import net.rim.device.api.ui.Manager; import net.rim.device.api.ui.MenuItem; import net.rim.device.api.ui.UiApplication; import net.rim.device.api.ui.component.BitmapField; import net.rim.device.api.ui.component.Dialog; import net.rim.device.api.ui.component.LabelField; import net.rim.device.api.ui.component.ListField; import net.rim.device.api.ui.component.ListFieldCallback; import net.rim.device.api.ui.component.NullField; import net.rim.device.api.ui.container.FullScreen; import net.rim.device.api.ui.container.MainScreen; import net.rim.device.api.ui.container.VerticalFieldManager; import net.rim.device.api.util.Arrays; import net.rim.device.api.ui.component.ListField; public class TaskListField extends UiApplication { // statics // ------------------------------------------------------------------ public static void main(String[] args) { TaskListField theApp = new TaskListField(); theApp.enterEventDispatcher(); } public TaskListField() { pushScreen(new TaskList()); } } class TaskList extends MainScreen implements ListFieldCallback { private Vector rows; private Bitmap p1; private Bitmap p2; private Bitmap p3; String Task; ListField listnew = new ListField(); private VerticalFieldManager metadataVFM; TableRowManager row; public TaskList() { super(); URLBitmapField artistImgField; listnew.setRowHeight(80); listnew.setCallback(this); rows = new Vector(); for (int x = 0; x <3; x++) { row = new TableRowManager(); artistImgField = new URLBitmapField(Bitmap .getBitmapResource("res/images/bg.jpg")); row.add(artistImgField); String photoURL = "someimagefrmurl.jpg"; Log.info(photoURL); // strip white spaces in the url, which is causing the // images to not display properly for (int i = 0; i < photoURL.length(); i++) { if (photoURL.charAt(i) == ' ') { photoURL = photoURL.substring(0, i) + "%20" + photoURL.substring(i + 1, photoURL.length()); } } Log.info("Processed URL: " + photoURL); artistImgField.setURL(photoURL); LabelField task = new LabelField("Display"); row.add(task); LabelField task1 = new LabelField( "Now Playing" + String.valueOf(x)); Font myFont = Font.getDefault().derive(Font.PLAIN, 12); task1.setFont(myFont); row.add(task1); rows.addElement(row); } listnew.setSize(rows.size()); this.add(listnew); //listnew.invalidate(); } // ListFieldCallback Implementation public void drawListRow(ListField listField, Graphics g, int index, int y, int width) { TableRowManager rowManager = (TableRowManager) rows.elementAt(index); rowManager.drawRow(g, 0, y, width, listnew.getRowHeight()); } protected void drawFocus(Graphics graphics, boolean on) { } private class TableRowManager extends Manager { public TableRowManager() { super(0); } // Causes the fields within this row manager to be layed out then // painted. public void drawRow(Graphics g, int x, int y, int width, int height) { // Arrange the cell fields within this row manager. layout(width, height); // Place this row manager within its enclosing list. setPosition(x, y); // Apply a translating/clipping transformation to the graphics // context so that this row paints in the right area. g.pushRegion(getExtent()); // Paint this manager's controlled fields. subpaint(g); g.setColor(0x00CACACA); g.drawLine(0, 0, getPreferredWidth(), 0); // Restore the graphics context. g.popContext(); } // Arrages this manager's controlled fields from left to right within // the enclosing table's columns. protected void sublayout(int width, int height) { // set the size and position of each field. int fontHeight = Font.getDefault().getHeight(); int preferredWidth = getPreferredWidth(); // start with the Bitmap Field of the priority icon Field field = getField(0); layoutChild(field, 146,80); setPositionChild(field, 0, 0); // set the task name label field field = getField(1); layoutChild(field, preferredWidth - 16, fontHeight + 1); setPositionChild(field, 149, 3); // set the list name label field field = getField(2); layoutChild(field, 150, fontHeight + 1); setPositionChild(field, 149, fontHeight + 6); setExtent(360, 480); } // The preferred width of a row is defined by the list renderer. public int getPreferredWidth() { return listnew.getWidth(); } // The preferred height of a row is the "row height" as defined in the // enclosing list. public int getPreferredHeight() { return listnew.getRowHeight(); } } public Object get(ListField listField, int index) { // TODO Auto-generated method stub return null; } public int getPreferredWidth(ListField listField) { return 0; } public int indexOfList(ListField listField, String prefix, int start) { // TODO Auto-generated method stub return 0; } }

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  • Set postion in customized list field in blackberry

    - by arunabha
    I want three list field items to be displayed, from bottom to top. I am able to display three list field items, but they display from top to bottom. I have tried setting the position, but it isn't working. import java.util.Vector; import net.rim.device.api.system.Bitmap; import net.rim.device.api.system.Display; import net.rim.device.api.ui.ContextMenu; import net.rim.device.api.ui.DrawStyle; import net.rim.device.api.ui.Field; import net.rim.device.api.ui.Font; import net.rim.device.api.ui.Graphics; import net.rim.device.api.ui.Manager; import net.rim.device.api.ui.MenuItem; import net.rim.device.api.ui.UiApplication; import net.rim.device.api.ui.component.BitmapField; import net.rim.device.api.ui.component.Dialog; import net.rim.device.api.ui.component.LabelField; import net.rim.device.api.ui.component.ListField; import net.rim.device.api.ui.component.ListFieldCallback; import net.rim.device.api.ui.component.NullField; import net.rim.device.api.ui.container.FullScreen; import net.rim.device.api.ui.container.MainScreen; import net.rim.device.api.util.Arrays; import net.rim.device.api.ui.component.ListField; /** * @author Jason Emerick */ public class TaskListField extends UiApplication { //statics ------------------------------------------------------------------ public static void main(String[] args) { TaskListField theApp = new TaskListField(); theApp.enterEventDispatcher(); } public TaskListField() { pushScreen(new TaskList()); } } /*class List extends FullScreen { TaskList tl; List(){ super(); TaskList tl=new TaskList(); } }*/ class TaskList extends MainScreen implements ListFieldCallback { private Vector rows; private Bitmap p1; private Bitmap p2; private Bitmap p3; String Task; ListField listnew=new ListField(); public TaskList() { super(); listnew.setRowHeight(50); //setEmptyString("Hooray, no tasks here!", DrawStyle.HCENTER); listnew.setCallback(this); p1 = Bitmap.getBitmapResource("1.png"); p2 = Bitmap.getBitmapResource("2.png"); p3 = Bitmap.getBitmapResource("3.png"); rows = new Vector(); for (int x = 0; x < 3; x++) { TableRowManager row = new TableRowManager(); if (x== 0) { Task="On Air Now"; } if (x== 1) { Task="Music Channel"; } if (x==2) { Task="News Channel"; } // SET THE PRIORITY BITMAP FIELD // if high priority, display p1 bitmap if (x % 2 == 0) { row.add(new BitmapField(p1)); } // if priority is 2, set p2 bitmap else if (x % 3 == 0) { row.add(new BitmapField(p2)); } // if priority is 3, set p3 bitmap else { row.add(new BitmapField(p3)); } // SET THE TASK NAME LABELFIELD // if overdue, bold/underline LabelField task = new LabelField(Task, DrawStyle.ELLIPSIS); // if due today, bold if (x % 2 == 0) { task.setFont(Font.getDefault().derive( Font.BOLD)); } else { task.setFont(Font.getDefault().derive(Font.BOLD)); } row.add(task); LabelField task1 = new LabelField("Now Playing" + String.valueOf(x), DrawStyle.ELLIPSIS); // if due today, bold /* if (x % 2 == 0) { task.setFont(Font.getDefault().derive( Font.BOLD)); } else { task.setFont(Font.getDefault().derive(Font.BOLD)); }*/ Font myFont = Font.getDefault().derive(Font.PLAIN, 12); task1.setFont(myFont); row.add(task1); // SET THE DUE DATE/TIME row.add(new LabelField("", DrawStyle.ELLIPSIS | LabelField.USE_ALL_WIDTH | DrawStyle.RIGHT) { protected void paint(Graphics graphics) { graphics.setColor(0x00878787); super.paint(graphics); } }); rows.addElement(row); } listnew.setSize(rows.size()); this.add(listnew); } // ListFieldCallback Implementation public void drawListRow(ListField listField, Graphics g, int index, int y, int width) { //TaskList list =(TaskListField) listnew; TableRowManager rowManager = (TableRowManager)rows .elementAt(index); rowManager.drawRow(g, 0, y, width, listnew.getRowHeight()); } private class TableRowManager extends Manager { public TableRowManager() { super(0); } // Causes the fields within this row manager to be layed out then // painted. public void drawRow(Graphics g, int x, int y, int width, int height) { // Arrange the cell fields within this row manager. layout(0, 1); // Place this row manager within its enclosing list. setPosition(x,y); // Apply a translating/clipping transformation to the graphics // context so that this row paints in the right area. g.pushRegion(getExtent()); // Paint this manager's controlled fields. subpaint(g); g.setColor(0x00CACACA); g.drawLine(0, 0, getPreferredWidth(), 0); // Restore the graphics context. g.popContext(); } // Arrages this manager's controlled fields from left to right within // the enclosing table's columns. protected void sublayout(int width, int height) { // set the size and position of each field. int fontHeight = Font.getDefault().getHeight(); int preferredWidth = getPreferredWidth(); // start with the Bitmap Field of the priority icon /* Field field = getField(0); layoutChild(field, 0, 0); setPositionChild(field, 150, 300);*/ // set the task name label field /* field = getField(1); layoutChild(field, preferredWidth - 16, fontHeight + 1); setPositionChild(field, 34, 3); // set the list name label field field = getField(2); layoutChild(field, 150, fontHeight + 1); setPositionChild(field, 34, fontHeight + 6);*/ // set the due time name label field /* field = getField(3); layoutChild(field, 150, fontHeight + 1); setPositionChild(field,4,340);*/ /* layoutChild(listnew, preferredWidth, fontHeight); setPositionChild(listnew, 3, 396);*/ setExtent(360, 480); } // The preferred width of a row is defined by the list renderer. public int getPreferredWidth() { return getWidth(); } // The preferred height of a row is the "row height" as defined in the // enclosing list. public int getPreferredHeight() { return listnew.getRowHeight(); } } public Object get(ListField listField, int index) { // TODO Auto-generated method stub return null; } public int getPreferredWidth(ListField listField) { // TODO Auto-generated method stub return 0; } public int indexOfList(ListField listField, String prefix, int start) { // TODO Auto-generated method stub return 0; } }

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  • Returning new object, overwrite the existing one in Java

    - by lupin
    Note: This is an assignment. Hi, Ok I have this method that will create a supposedly union of 2 sets. i mport java.io.*; class Set { public int numberOfElements; public String[] setElements; public int maxNumberOfElements; // constructor for our Set class public Set(int numberOfE, int setE, int maxNumberOfE) { this.numberOfElements = numberOfE; this.setElements = new String[setE]; this.maxNumberOfElements = maxNumberOfE; } // Helper method to shorten/remove element of array since we're using basic array instead of ArrayList or HashSet from collection interface :( static String[] removeAt(int k, String[] arr) { final int L = arr.length; String[] ret = new String[L - 1]; System.arraycopy(arr, 0, ret, 0, k); System.arraycopy(arr, k + 1, ret, k, L - k - 1); return ret; } int findElement(String element) { int retval = 0; for ( int i = 0; i < setElements.length; i++) { if ( setElements[i] != null && setElements[i].equals(element) ) { return retval = i; } retval = -1; } return retval; } void add(String newValue) { int elem = findElement(newValue); if( numberOfElements < maxNumberOfElements && elem == -1 ) { setElements[numberOfElements] = newValue; numberOfElements++; } } int getLength() { if ( setElements != null ) { return setElements.length; } else { return 0; } } String[] emptySet() { setElements = new String[0]; return setElements; } Boolean isFull() { Boolean True = new Boolean(true); Boolean False = new Boolean(false); if ( setElements.length == maxNumberOfElements ){ return True; } else { return False; } } Boolean isEmpty() { Boolean True = new Boolean(true); Boolean False = new Boolean(false); if ( setElements.length == 0 ) { return True; } else { return False; } } void remove(String newValue) { for ( int i = 0; i < setElements.length; i++) { if ( setElements[i] != null && setElements[i].equals(newValue) ) { setElements = removeAt(i,setElements); } } } int isAMember(String element) { int retval = -1; for ( int i = 0; i < setElements.length; i++ ) { if (setElements[i] != null && setElements[i].equals(element)) { return retval = i; } } return retval; } void printSet() { for ( int i = 0; i < setElements.length; i++) { if (setElements[i] != null) { System.out.println("Member elements on index: "+ i +" " + setElements[i]); } } } String[] getMember() { String[] tempArray = new String[setElements.length]; for ( int i = 0; i < setElements.length; i++) { if(setElements[i] != null) { tempArray[i] = setElements[i]; } } return tempArray; } Set union(Set x, Set y) { String[] newXtemparray = new String[x.getLength()]; String[] newYtemparray = new String[y.getLength()]; int len = newYtemparray.length + newXtemparray.length; Set temp = new Set(0,len,len); newXtemparray = x.getMember(); newYtemparray = x.getMember(); for(int i = 0; i < newYtemparray.length; i++) { temp.add(newYtemparray[i]); } for(int j = 0; j < newXtemparray.length; j++) { temp.add(newXtemparray[j]); } return temp; } Set difference(Set x, Set y) { String[] newXtemparray = new String[x.getLength()]; String[] newYtemparray = new String[y.getLength()]; int len = newYtemparray.length + newXtemparray.length; Set temp = new Set(0,len,len); newXtemparray = x.getMember(); newYtemparray = x.getMember(); for(int i = 0; i < newXtemparray.length; i++) { temp.add(newYtemparray[i]); } for(int j = 0; j < newYtemparray.length; j++) { int retval = temp.findElement(newYtemparray[j]); if( retval != -1 ) { temp.remove(newYtemparray[j]); } } return temp; } } // This is the SetDemo class that will make use of our Set class class SetDemo { public static void main(String[] args) { //get input from keyboard BufferedReader keyboard; InputStreamReader reader; String temp = ""; reader = new InputStreamReader(System.in); keyboard = new BufferedReader(reader); try { System.out.println("Enter string element to be added" ); temp = keyboard.readLine( ); System.out.println("You entered " + temp ); } catch (IOException IOerr) { System.out.println("There was an error during input"); } /* ************************************************************************** * Test cases for our new created Set class. * ************************************************************************** */ Set setA = new Set(0,10,10); setA.add(temp); setA.add("b"); setA.add("b"); setA.add("hello"); setA.add("world"); setA.add("six"); setA.add("seven"); setA.add("b"); int size = setA.getLength(); System.out.println("Set size is: " + size ); Boolean isempty = setA.isEmpty(); System.out.println("Set is empty? " + isempty ); int ismember = setA.isAMember("sixb"); System.out.println("Element sixb is member of setA? " + ismember ); Boolean output = setA.isFull(); System.out.println("Set is full? " + output ); //setA.printSet(); int index = setA.findElement("world"); System.out.println("Element b located on index: " + index ); setA.remove("b"); //setA.emptySet(); int resize = setA.getLength(); System.out.println("Set size is: " + resize ); //setA.printSet(); Set setB = new Set(0,10,10); setB.add("b"); setB.add("z"); setB.add("x"); setB.add("y"); Set setC = setA.union(setB,setA); System.out.println("Elements of setA"); setA.printSet(); System.out.println("Union of setA and setB"); setC.printSet(); } } The union method works a sense that somehow I can call another method on it but it doesn't do the job, i supposedly would create and union of all elements of setA and setB but it only return element of setB. Sample output follows: java SetDemo Enter string element to be added hello You entered hello Set size is: 10 Set is empty? false Element sixb is member of setA? -1 Set is full? true Element b located on index: 2 Set size is: 9 Elements of setA Member elements on index: 0 hello Member elements on index: 1 world Member elements on index: 2 six Member elements on index: 3 seven Union of setA and setB Member elements on index: 0 b Member elements on index: 1 z Member elements on index: 2 x Member elements on index: 3 y thanks, lupin

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  • Java constructor and modify the object properties at runtime

    - by lupin
    Note: This is an assignment Hi, I have the following class/constructor. import java.io.*; class Set { public int numberOfElements = 0; public String[] setElements = new String[5]; public int maxNumberOfElements = 5; // constructor for our Set class public Set(int numberOfE, int setE, int maxNumberOfE) { int numberOfElements = numberOfE; String[] setElements = new String[setE]; int maxNumberOfElements = maxNumberOfE; } // Helper method to shorten/remove element of array since we're using basic array instead of ArrayList or HashSet from collection interface :( static String[] removeAt(int k, String[] arr) { final int L = arr.length; String[] ret = new String[L - 1]; System.arraycopy(arr, 0, ret, 0, k); System.arraycopy(arr, k + 1, ret, k, L - k - 1); return ret; } int findElement(String element) { int retval = 0; for ( int i = 0; i < setElements.length; i++) { if ( setElements[i] != null && setElements[i].equals(element) ) { return retval = i; } retval = -1; } return retval; } void add(String newValue) { int elem = findElement(newValue); if( numberOfElements < maxNumberOfElements && elem == -1 ) { setElements[numberOfElements] = newValue; numberOfElements++; } } int getLength() { if ( setElements != null ) { return setElements.length; } else { return 0; } } String[] emptySet() { setElements = new String[0]; return setElements; } Boolean isFull() { Boolean True = new Boolean(true); Boolean False = new Boolean(false); if ( setElements.length == maxNumberOfElements ){ return True; } else { return False; } } Boolean isEmpty() { Boolean True = new Boolean(true); Boolean False = new Boolean(false); if ( setElements.length == 0 ) { return True; } else { return False; } } void remove(String newValue) { for ( int i = 0; i < setElements.length; i++) { if ( setElements[i].equals(newValue) ) { setElements = removeAt(i,setElements); } } } int isAMember(String element) { int retval = -1; for ( int i = 0; i < setElements.length; i++ ) { if (setElements[i] != null && setElements[i].equals(element)) { return retval = i; } } return retval; } void printSet() { for ( int i = 0; i < setElements.length; i++) { System.out.println("Member elements on index: "+ i +" " + setElements[i]); } } String[] getMember() { String[] tempArray = new String[setElements.length]; for ( int i = 0; i < setElements.length; i++) { if(setElements[i] != null) { tempArray[i] = setElements[i]; } } return tempArray; } Set union(Set x, Set y) { String[] newXtemparray = new String[x.getLength()]; String[] newYtemparray = new String[y.getLength()]; Set temp = new Set(1,20,20); newXtemparray = x.getMember(); newYtemparray = x.getMember(); for(int i = 0; i < newXtemparray.length; i++) { temp.add(newYtemparray[i]); } for(int j = 0; j < newYtemparray.length; j++) { temp.add(newYtemparray[j]); } return temp; } } // This is the SetDemo class that will make use of our Set class class SetDemo { public static void main(String[] args) { //get input from keyboard BufferedReader keyboard; InputStreamReader reader; String temp = ""; reader = new InputStreamReader(System.in); keyboard = new BufferedReader(reader); try { System.out.println("Enter string element to be added" ); temp = keyboard.readLine( ); System.out.println("You entered " + temp ); } catch (IOException IOerr) { System.out.println("There was an error during input"); } /* ************************************************************************** * Test cases for our new created Set class. * ************************************************************************** */ Set setA = new Set(1,10,10); setA.add(temp); setA.add("b"); setA.add("b"); setA.add("hello"); setA.add("world"); setA.add("six"); setA.add("seven"); setA.add("b"); int size = setA.getLength(); System.out.println("Set size is: " + size ); Boolean isempty = setA.isEmpty(); System.out.println("Set is empty? " + isempty ); int ismember = setA.isAMember("sixb"); System.out.println("Element six is member of setA? " + ismember ); Boolean output = setA.isFull(); System.out.println("Set is full? " + output ); setA.printSet(); int index = setA.findElement("world"); System.out.println("Element b located on index: " + index ); setA.remove("b"); setA.emptySet(); int resize = setA.getLength(); System.out.println("Set size is: " + resize ); setA.printSet(); Set setB = new Set(0,10,10); Set SetA = setA.union(setB,setA); SetA.printSet(); } } I have two question here, why I when I change the class property declaration to: class Set { public int numberOfElements; public String[] setElements; public int maxNumberOfElements; // constructor for our Set class public Set(int numberOfE, int setE, int maxNumberOfE) { int numberOfElements = numberOfE; String[] setElements = new String[setE]; int maxNumberOfElements = maxNumberOfE; } I got this error: \ javaprojects>java SetDemo Enter string element to be added a You entered a Exception in thread "main" java.lang.NullPointerException at Set.findElement(Set.java:30) at Set.add(Set.java:43) at SetDemo.main(Set.java:169) Second, on the union method, why the result of SetA.printSet still printing null, isn't it getting back the return value from union method? Thanks in advance for any explaination. lupin

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  • Maze not generating properly. Out of bounds exception. need quick fix

    - by Dan Joseph Porcioncula
    My maze generator seems to have a problem. I am trying to generate something like the maze from http://mazeworks.com/mazegen/mazetut/index.htm . My program displays this http://a1.sphotos.ak.fbcdn.net/hphotos-ak-snc7/s320x320/374060_426350204045347_100000111130260_1880768_1572427285_n.jpg and the error Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: -1 at Grid.genRand(Grid.java:73) at Grid.main(Grid.java:35) How do I fix my generator program? import java.awt.*; import java.awt.Color; import java.awt.Component; import java.awt.Graphics; import javax.swing.*; import java.util.ArrayList; public class Grid extends Canvas { Cell[][] maze; int size; int pathSize; double width, height; ArrayList<int[]> coordinates = new ArrayList<int[]>(); public Grid(int size, int h, int w) { this.size = size; maze = new Cell[size][size]; for(int i = 0; i<size; i++){ for(int a =0; a<size; a++){ maze[i][a] = new Cell(); } } setPreferredSize(new Dimension(h, w)); } public static void main(String[] args) { JFrame y = new JFrame(); y.setLayout(new BorderLayout()); Grid f = new Grid(25, 400, 400); y.add(f, BorderLayout.CENTER); y.setSize(450, 450); y.setVisible(true); y.setDefaultCloseOperation(y.EXIT_ON_CLOSE); f.genRand(); f.repaint(); } public void push(int[] xy) { coordinates.add(xy); int i = coordinates.size(); coordinates.ensureCapacity(i++); } public int[] pop() { int[] x = coordinates.get((coordinates.size())-1); coordinates.remove((coordinates.size())-1); return x; } public int[] top() { return coordinates.get((coordinates.size())-1); } public void genRand(){ // create a CellStack (LIFO) to hold a list of cell locations [x] // set TotalCells = number of cells in grid int TotalCells = size*size; // choose a cell at random and call it CurrentCell int m = randomInt(size); int n = randomInt(size); Cell curCel = maze[m][n]; // set VisitedCells = 1 int visCel = 1,d=0; int[] q; int h,o = 0,p = 0; // while VisitedCells < TotalCells while( visCel < TotalCells){ // find all neighbors of CurrentCell with all walls intact if(maze[m-1][n].countWalls() == 4){d++;} if(maze[m+1][n].countWalls() == 4){d++;} if(maze[m][n-1].countWalls() == 4){d++;} if(maze[m][n+1].countWalls() == 4){d++;} // if one or more found if(d!=0){ Point[] ls = new Point[4]; ls[0] = new Point(m-1,n); ls[1] = new Point(m+1,n); ls[2] = new Point(m,n-1); ls[3] = new Point(m,n+1); // knock down the wall between it and CurrentCell h = randomInt(3); switch(h){ case 0: o = (int)(ls[0].getX()); p = (int)(ls[0].getY()); curCel.destroyWall(2); maze[o][p].destroyWall(1); break; case 1: o = (int)(ls[1].getX()); p = (int)(ls[1].getY()); curCel.destroyWall(1); maze[o][p].destroyWall(2); break; case 2: o = (int)(ls[2].getX()); p = (int)(ls[2].getY()); curCel.destroyWall(3); maze[o][p].destroyWall(0); break; case 3: o = (int)(ls[3].getX()); p = (int)(ls[3].getY()); curCel.destroyWall(0); maze[o][p].destroyWall(3); break; } // push CurrentCell location on the CellStack push(new int[] {m,n}); // make the new cell CurrentCell m = o; n = p; curCel = maze[m][n]; // add 1 to VisitedCells visCel++; } // else else{ // pop the most recent cell entry off the CellStack q = pop(); m = q[0]; n = q[1]; curCel = maze[m][n]; // make it CurrentCell // endIf } // endWhile } } public int randomInt(int s) { return (int)(s* Math.random());} public void paint(Graphics g) { int k, j; width = getSize().width; height = getSize().height; double htOfRow = height / (size); double wdOfRow = width / (size); //checks verticals - destroys east border of cell for (k = 0; k < size; k++) { for (j = 0; j < size; j++) { if(maze[k][j].checkWall(2)){ g.drawLine((int) (k * wdOfRow), (int) (j * htOfRow), (int) (k * wdOfRow), (int) ((j+1) * htOfRow)); }} } //checks horizontal - destroys north border of cell for (k = 0; k < size; k++) { for (j = 0; j < size; j++) { if(maze[k][j].checkWall(3)){ g.drawLine((int) (k * wdOfRow), (int) (j * htOfRow), (int) ((k+1) * wdOfRow), (int) (j * htOfRow)); }} } } } class Cell { private final static int NORTH = 0; private final static int EAST = 1; private final static int WEST = 2; private final static int SOUTH = 3; private final static int NO = 4; private final static int START = 1; private final static int END = 2; boolean[] wall = new boolean[4]; boolean[] border = new boolean[4]; boolean[] backtrack = new boolean[4]; boolean[] solution = new boolean[4]; private boolean isVisited = false; private int Key = 0; public Cell(){ for(int i=0;i<4;i++){wall[i] = true;} } public int countWalls(){ int i, k =0; for(i=0; i<4; i++) { if (wall[i] == true) {k++;} } return k;} public boolean checkWall(int x){ switch(x){ case 0: return wall[0]; case 1: return wall[1]; case 2: return wall[2]; case 3: return wall[3]; } return true; } public void destroyWall(int x){ switch(x){ case 0: wall[0] = false; break; case 1: wall[1] = false; break; case 2: wall[2] = false; break; case 3: wall[3] = false; break; } } public void setStart(int i){Key = i;} public int getKey(){return Key;} public boolean checkVisit(){return isVisited;} public void visitCell(){isVisited = true;} }

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  • SQL error - Cannot convert nvarchar to decimal

    - by jakesankey
    I have a C# application that simply parses all of the txt documents within a given network directory and imports the data to a SQL server db. Everything was cruising along just fine until about the 1800th file when it happend to have a few blanks in columns that are called out as DBType.Decimal (and the value is usually zero in the files, not blank). So I got this error, "cannot convert nvarchar to decimal". I am wondering how I could tell the app to simply skip the lines that have this issue?? Perhaps I could even just change the column type to varchar even tho values are numbers (what problems could this create?) Thanks for any help! using System; using System.Data; using System.Data.SQLite; using System.IO; using System.Text.RegularExpressions; using System.Threading; using System.Collections.Generic; using System.Linq; using System.Data.SqlClient; namespace JohnDeereCMMDataParser { internal class Program { public static List<string> GetImportedFileList() { List<string> ImportedFiles = new List<string>(); using (SqlConnection connect = new SqlConnection(@"Server=FRXSQLDEV;Database=RX_CMMData;Integrated Security=YES")) { connect.Open(); using (SqlCommand fmd = connect.CreateCommand()) { fmd.CommandText = @"SELECT FileName FROM CMMData;"; fmd.CommandType = CommandType.Text; SqlDataReader r = fmd.ExecuteReader(); while (r.Read()) { ImportedFiles.Add(Convert.ToString(r["FileName"])); } } } return ImportedFiles; } private static void Main(string[] args) { Console.Title = "John Deere CMM Data Parser"; Console.WriteLine("Preparing CMM Data Parser... done"); Console.WriteLine("Scanning for new CMM data..."); Console.ForegroundColor = ConsoleColor.Gray; using (SqlConnection con = new SqlConnection(@"Server=FRXSQLDEV;Database=RX_CMMData;Integrated Security=YES")) { con.Open(); using (SqlCommand insertCommand = con.CreateCommand()) { Console.WriteLine("Connecting to SQL server..."); SqlCommand cmdd = con.CreateCommand(); string[] files = Directory.GetFiles(@"C:\Documents and Settings\js91162\Desktop\CMM WENZEL\", "*_*_*.txt", SearchOption.AllDirectories); List<string> ImportedFiles = GetImportedFileList(); insertCommand.Parameters.Add(new SqlParameter("@FeatType", DbType.String)); insertCommand.Parameters.Add(new SqlParameter("@FeatName", DbType.String)); insertCommand.Parameters.Add(new SqlParameter("@Axis", DbType.String)); insertCommand.Parameters.Add(new SqlParameter("@Actual", DbType.Decimal)); insertCommand.Parameters.Add(new SqlParameter("@Nominal", DbType.Decimal)); insertCommand.Parameters.Add(new SqlParameter("@Dev", DbType.Decimal)); insertCommand.Parameters.Add(new SqlParameter("@TolMin", DbType.Decimal)); insertCommand.Parameters.Add(new SqlParameter("@TolPlus", DbType.Decimal)); insertCommand.Parameters.Add(new SqlParameter("@OutOfTol", DbType.Decimal)); foreach (string file in files.Except(ImportedFiles)) { var FileNameExt1 = Path.GetFileName(file); cmdd.Parameters.Clear(); cmdd.Parameters.Add(new SqlParameter("@FileExt", FileNameExt1)); cmdd.CommandText = @" IF (EXISTS (SELECT * FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA = 'RX_CMMData' AND TABLE_NAME = 'CMMData')) BEGIN SELECT COUNT(*) FROM CMMData WHERE FileName = @FileExt; END"; int count = Convert.ToInt32(cmdd.ExecuteScalar()); con.Close(); con.Open(); if (count == 0) { Console.WriteLine("Preparing to parse CMM data for SQL import..."); if (file.Count(c => c == '_') > 5) continue; insertCommand.CommandText = @" INSERT INTO CMMData (FeatType, FeatName, Axis, Actual, Nominal, Dev, TolMin, TolPlus, OutOfTol, PartNumber, CMMNumber, Date, FileName) VALUES (@FeatType, @FeatName, @Axis, @Actual, @Nominal, @Dev, @TolMin, @TolPlus, @OutOfTol, @PartNumber, @CMMNumber, @Date, @FileName);"; string FileNameExt = Path.GetFullPath(file); string RNumber = Path.GetFileNameWithoutExtension(file); int index2 = RNumber.IndexOf("~"); Match RNumberE = Regex.Match(RNumber, @"^(R|L)\d{6}(COMP|CRIT|TEST|SU[1-9])(?=_)", RegexOptions.IgnoreCase); Match RNumberD = Regex.Match(RNumber, @"(?<=_)\d{3}[A-Z]\d{4}|\d{3}[A-Z]\d\w\w\d(?=_)", RegexOptions.IgnoreCase); Match RNumberDate = Regex.Match(RNumber, @"(?<=_)\d{8}(?=_)", RegexOptions.IgnoreCase); string RNumE = Convert.ToString(RNumberE); string RNumD = Convert.ToString(RNumberD); if (RNumberD.Value == @"") continue; if (RNumberE.Value == @"") continue; if (RNumberDate.Value == @"") continue; if (index2 != -1) continue; DateTime dateTime = DateTime.ParseExact(RNumberDate.Value, "yyyyMMdd", Thread.CurrentThread.CurrentCulture); string cmmDate = dateTime.ToString("dd-MMM-yyyy"); string[] lines = File.ReadAllLines(file); bool parse = false; foreach (string tmpLine in lines) { string line = tmpLine.Trim(); if (!parse && line.StartsWith("Feat. Type,")) { parse = true; continue; } if (!parse || string.IsNullOrEmpty(line)) { continue; } Console.WriteLine(tmpLine); foreach (SqlParameter parameter in insertCommand.Parameters) { parameter.Value = null; } string[] values = line.Split(new[] { ',' }); for (int i = 0; i < values.Length - 1; i++) { if (i = "" || i = null) continue; SqlParameter param = insertCommand.Parameters[i]; if (param.DbType == DbType.Decimal) { decimal value; param.Value = decimal.TryParse(values[i], out value) ? value : 0; } else { param.Value = values[i]; } } insertCommand.Parameters.Add(new SqlParameter("@PartNumber", RNumE)); insertCommand.Parameters.Add(new SqlParameter("@CMMNumber", RNumD)); insertCommand.Parameters.Add(new SqlParameter("@Date", cmmDate)); insertCommand.Parameters.Add(new SqlParameter("@FileName", FileNameExt)); insertCommand.ExecuteNonQuery(); insertCommand.Parameters.RemoveAt("@PartNumber"); insertCommand.Parameters.RemoveAt("@CMMNumber"); insertCommand.Parameters.RemoveAt("@Date"); insertCommand.Parameters.RemoveAt("@FileName"); } } } Console.WriteLine("CMM data successfully imported to SQL database..."); } con.Close(); } } } }

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  • F# - Facebook Hacker Cup - Double Squares

    - by Jacob
    I'm working on strengthening my F#-fu and decided to tackle the Facebook Hacker Cup Double Squares problem. I'm having some problems with the run-time and was wondering if anyone could help me figure out why it is so much slower than my C# equivalent. There's a good description from another post; Source: Facebook Hacker Cup Qualification Round 2011 A double-square number is an integer X which can be expressed as the sum of two perfect squares. For example, 10 is a double-square because 10 = 3^2 + 1^2. Given X, how can we determine the number of ways in which it can be written as the sum of two squares? For example, 10 can only be written as 3^2 + 1^2 (we don't count 1^2 + 3^2 as being different). On the other hand, 25 can be written as 5^2 + 0^2 or as 4^2 + 3^2. You need to solve this problem for 0 = X = 2,147,483,647. Examples: 10 = 1 25 = 2 3 = 0 0 = 1 1 = 1 My basic strategy (which I'm open to critique on) is to; Create a dictionary (for memoize) of the input numbers initialzed to 0 Get the largest number (LN) and pass it to count/memo function Get the LN square root as int Calculate squares for all numbers 0 to LN and store in dict Sum squares for non repeat combinations of numbers from 0 to LN If sum is in memo dict, add 1 to memo Finally, output the counts of the original numbers. Here is the F# code (See code changes at bottom) I've written that I believe corresponds to this strategy (Runtime: ~8:10); open System open System.Collections.Generic open System.IO /// Get a sequence of values let rec range min max = seq { for num in [min .. max] do yield num } /// Get a sequence starting from 0 and going to max let rec zeroRange max = range 0 max /// Find the maximum number in a list with a starting accumulator (acc) let rec maxNum acc = function | [] -> acc | p::tail when p > acc -> maxNum p tail | p::tail -> maxNum acc tail /// A helper for finding max that sets the accumulator to 0 let rec findMax nums = maxNum 0 nums /// Build a collection of combinations; ie [1,2,3] = (1,1), (1,2), (1,3), (2,2), (2,3), (3,3) let rec combos range = seq { let count = ref 0 for inner in range do for outer in Seq.skip !count range do yield (inner, outer) count := !count + 1 } let rec squares nums = let dict = new Dictionary<int, int>() for s in nums do dict.[s] <- (s * s) dict /// Counts the number of possible double squares for a given number and keeps track of other counts that are provided in the memo dict. let rec countDoubleSquares (num: int) (memo: Dictionary<int, int>) = // The highest relevent square is the square root because it squared plus 0 squared is the top most possibility let maxSquare = System.Math.Sqrt((float)num) // Our relevant squares are 0 to the highest possible square; note the cast to int which shouldn't hurt. let relSquares = range 0 ((int)maxSquare) // calculate the squares up front; let calcSquares = squares relSquares // Build up our square combinations; ie [1,2,3] = (1,1), (1,2), (1,3), (2,2), (2,3), (3,3) for (sq1, sq2) in combos relSquares do let v = calcSquares.[sq1] + calcSquares.[sq2] // Memoize our relevant results if memo.ContainsKey(v) then memo.[v] <- memo.[v] + 1 // return our count for the num passed in memo.[num] // Read our numbers from file. //let lines = File.ReadAllLines("test2.txt") //let nums = [ for line in Seq.skip 1 lines -> Int32.Parse(line) ] // Optionally, read them from straight array let nums = [1740798996; 1257431873; 2147483643; 602519112; 858320077; 1048039120; 415485223; 874566596; 1022907856; 65; 421330820; 1041493518; 5; 1328649093; 1941554117; 4225; 2082925; 0; 1; 3] // Initialize our memoize dictionary let memo = new Dictionary<int, int>() for num in nums do memo.[num] <- 0 // Get the largest number in our set, all other numbers will be memoized along the way let maxN = findMax nums // Do the memoize let maxCount = countDoubleSquares maxN memo // Output our results. for num in nums do printfn "%i" memo.[num] // Have a little pause for when we debug let line = Console.Read() And here is my version in C# (Runtime: ~1:40: using System; using System.Collections.Generic; using System.Diagnostics; using System.IO; using System.Linq; using System.Text; namespace FBHack_DoubleSquares { public class TestInput { public int NumCases { get; set; } public List<int> Nums { get; set; } public TestInput() { Nums = new List<int>(); } public int MaxNum() { return Nums.Max(); } } class Program { static void Main(string[] args) { // Read input from file. //TestInput input = ReadTestInput("live.txt"); // As example, load straight. TestInput input = new TestInput { NumCases = 20, Nums = new List<int> { 1740798996, 1257431873, 2147483643, 602519112, 858320077, 1048039120, 415485223, 874566596, 1022907856, 65, 421330820, 1041493518, 5, 1328649093, 1941554117, 4225, 2082925, 0, 1, 3, } }; var maxNum = input.MaxNum(); Dictionary<int, int> memo = new Dictionary<int, int>(); foreach (var num in input.Nums) { if (!memo.ContainsKey(num)) memo.Add(num, 0); } DoMemoize(maxNum, memo); StringBuilder sb = new StringBuilder(); foreach (var num in input.Nums) { //Console.WriteLine(memo[num]); sb.AppendLine(memo[num].ToString()); } Console.Write(sb.ToString()); var blah = Console.Read(); //File.WriteAllText("out.txt", sb.ToString()); } private static int DoMemoize(int num, Dictionary<int, int> memo) { var highSquare = (int)Math.Floor(Math.Sqrt(num)); var squares = CreateSquareLookup(highSquare); var relSquares = squares.Keys.ToList(); Debug.WriteLine("Starting - " + num.ToString()); Debug.WriteLine("RelSquares.Count = {0}", relSquares.Count); int sum = 0; var index = 0; foreach (var square in relSquares) { foreach (var inner in relSquares.Skip(index)) { sum = squares[square] + squares[inner]; if (memo.ContainsKey(sum)) memo[sum]++; } index++; } if (memo.ContainsKey(num)) return memo[num]; return 0; } private static TestInput ReadTestInput(string fileName) { var lines = File.ReadAllLines(fileName); var input = new TestInput(); input.NumCases = int.Parse(lines[0]); foreach (var lin in lines.Skip(1)) { input.Nums.Add(int.Parse(lin)); } return input; } public static Dictionary<int, int> CreateSquareLookup(int maxNum) { var dict = new Dictionary<int, int>(); int square; foreach (var num in Enumerable.Range(0, maxNum)) { square = num * num; dict[num] = square; } return dict; } } } Thanks for taking a look. UPDATE Changing the combos function slightly will result in a pretty big performance boost (from 8 min to 3:45): /// Old and Busted... let rec combosOld range = seq { let rangeCache = Seq.cache range let count = ref 0 for inner in rangeCache do for outer in Seq.skip !count rangeCache do yield (inner, outer) count := !count + 1 } /// The New Hotness... let rec combos maxNum = seq { for i in 0..maxNum do for j in i..maxNum do yield i,j }

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  • login form with java/sqlite

    - by tuxou
    hi I would like to create a login form for my application with the possibility to add or remove users for an sqlite database, i have created the table users(nam, pass) but i can't unclud it in my login form, it someone could help me this is my login code: import java.awt.*; import java.awt.event.*; import javax.swing.*; public class login extends JFrame{ // Variables declaration private JLabel jLabel1; private JLabel jLabel2; private JTextField jTextField1; private JPasswordField jPasswordField1; private JButton jButton1; private JPanel contentPane; // End of variables declaration public login(){ super(); create(); this.setVisible(true); } private void create(){ jLabel1 = new JLabel(); jLabel2 = new JLabel(); jTextField1 = new JTextField(); jPasswordField1 = new JPasswordField(); jButton1 = new JButton(); contentPane = (JPanel)this.getContentPane(); // // jLabel1 // jLabel1.setHorizontalAlignment(SwingConstants.LEFT); jLabel1.setForeground(new Color(0, 0, 255)); jLabel1.setText("username:"); // // jLabel2 // jLabel2.setHorizontalAlignment(SwingConstants.LEFT); jLabel2.setForeground(new Color(0, 0, 255)); jLabel2.setText("password:"); // // jTextField1 // jTextField1.setForeground(new Color(0, 0, 255)); jTextField1.setSelectedTextColor(new Color(0, 0, 255)); jTextField1.setToolTipText("Enter your username"); jTextField1.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e){ jTextField1_actionPerformed(e); } }); // // jPasswordField1 // jPasswordField1.setForeground(new Color(0, 0, 255)); jPasswordField1.setToolTipText("Enter your password"); jPasswordField1.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e){ jPasswordField1_actionPerformed(e); } }); // // jButton1 // jButton1.setBackground(new Color(204, 204, 204)); jButton1.setForeground(new Color(0, 0, 255)); jButton1.setText("Login"); jButton1.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e){ jButton1_actionPerformed(e); } }); // // contentPane // contentPane.setLayout(null); contentPane.setBorder(BorderFactory.createEtchedBorder()); contentPane.setBackground(new Color(204, 204, 204)); addComponent(contentPane, jLabel1, 5,10,106,18); addComponent(contentPane, jLabel2, 5,47,97,18); addComponent(contentPane, jTextField1, 110,10,183,22); addComponent(contentPane, jPasswordField1, 110,45,183,22); addComponent(contentPane, jButton1, 150,75,83,28); // // login // this.setTitle("Login To Members Area"); this.setLocation(new Point(76, 182)); this.setSize(new Dimension(335, 141)); this.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE); this.setResizable(false); } /** Add Component Without a Layout Manager (Absolute Positioning) */ private void addComponent(Container container,Component c,int x,int y,int width,int height){ c.setBounds(x,y,width,height); container.add(c); } private void jTextField1_actionPerformed(ActionEvent e){ } private void jPasswordField1_actionPerformed(ActionEvent e){ } private void jButton1_actionPerformed(ActionEvent e){ System.out.println("\njButton1_actionPerformed(ActionEvent e) called."); String username = new String(jTextField1.getText()); String password = new String(jPasswordField1.getText()); if(username.equals("") || password.equals("")){// If password and username is empty > Do this >>> jButton1.setEnabled(false); JLabel errorFields = new JLabel("<HTML><FONT COLOR = Blue>You must enter a username and password to login.</FONT></HTML>"); JOptionPane.showMessageDialog(null,errorFields); jTextField1.setText(""); jPasswordField1.setText(""); jButton1.setEnabled(true); this.setVisible(true); } else{ JLabel optionLabel = new JLabel("<HTML><FONT COLOR = Blue>You entered</FONT><FONT COLOR = RED> <B>"+username+"</B></FONT> <FONT COLOR = Blue>as your username.<BR> Is this correct?</FONT></HTML>"); int confirm =JOptionPane.showConfirmDialog(null,optionLabel); switch(confirm){ // Switch > Case case JOptionPane.YES_OPTION: // Attempt to Login user jButton1.setEnabled(false); // Set button enable to false to prevent 2 login attempts break; case JOptionPane.NO_OPTION: // No Case.(Go back. Set text to 0) jButton1.setEnabled(false); jTextField1.setText(""); jPasswordField1.setText(""); jButton1.setEnabled(true); break; case JOptionPane.CANCEL_OPTION: // Cancel Case.(Go back. Set text to 0) jButton1.setEnabled(false); jTextField1.setText(""); jPasswordField1.setText(""); jButton1.setEnabled(true); break; } // End Switch > Case } } public static void main(String[] args){ JFrame.setDefaultLookAndFeelDecorated(true); JDialog.setDefaultLookAndFeelDecorated(true); try{ UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel"); }catch (Exception ex){ System.out.println("Failed loading L&F: "); System.out.println(ex); } new login(); }; } my connectDb class : public class Connectdb { private static Connection connect; private static String url ="jdbc:sqlite:data.db"; private static Statement st; private static ResultSet rs; /** * Constructeur privé d'une connection à la bd unique */ private ConnectionBd(){ try { Class.forName("org.sqlite.JDBC"); connect = DriverManager.getConnection(url); } catch (ClassNotFoundException ex) { Logger.getLogger(ex.getName()).log(Level.SEVERE, null, ex); } catch (SQLException e) { System.exit(e.getErrorCode()); } } public static Connection getInstance(){ if(connect == null){ new Connectdb(); }else{ } return connect; } /** * @return */ public static void initTable(String query){ try { Statement state = getInstance().createStatement(ResultSet.TYPE_FORWARD_ONLY, ResultSet.CONCUR_READ_ONLY); ResultSet res = state.executeQuery(query); res.close(); state.close(); } catch (SQLException e) { JOptionPane.showMessageDialog(null, e.getMessage(), "ERROR ! ", JOptionPane.ERROR_MESSAGE); } }

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  • Probelm with String.split() in java

    - by Matt
    What I am trying to do is read a .java file, and pick out all of the identifiers and store them in a list. My problem is with the .split() method. If you run this code the way it is, you will get ArrayOutOfBounds, but if you change the delimiter from "." to anything else, the code works. But I need to lines parsed by "." so is there another way I could accomplish this? import java.io.BufferedReader; import java.io.FileNotFoundException; import java.io.FileReader; import java.io.IOException; import java.util.*; public class MyHash { private static String[] reserved = new String[100]; private static List list = new LinkedList(); private static List list2 = new LinkedList(); public static void main (String args[]){ Hashtable hashtable = new Hashtable(997); makeReserved(); readFile(); String line; ListIterator itr = list.listIterator(); int listIndex = 0; while (listIndex < list.size()) { if (itr.hasNext()){ line = itr.next().toString(); //PROBLEM IS HERE!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! String[] words = line.split("."); //CHANGE THIS AND IT WILL WORK System.out.println(words[0]); //TESTING TO SEE IF IT WORKED } listIndex++; } } public static void readFile() { String text; String[] words; BufferedReader in = null; try { in = new BufferedReader(new FileReader("MyHash.java")); //NAME OF INPUT FILE } catch (FileNotFoundException ex) { Logger.getLogger(MyHash.class.getName()).log(Level.SEVERE, null, ex); } try { while ((text = in.readLine()) != null){ text = text.trim(); words = text.split("\\s+"); for (int i = 0; i < words.length; i++){ list.add(words[i]); } for (int j = 0; j < reserved.length; j++){ if (list.contains(reserved[j])){ list.remove(reserved[j]); } } } } catch (IOException ex) { Logger.getLogger(MyHash.class.getName()).log(Level.SEVERE, null, ex); } try { in.close(); } catch (IOException ex) { Logger.getLogger(MyHash.class.getName()).log(Level.SEVERE, null, ex); } } public static int keyIt (int x) { int key = x % 997; return key; } public static int horner (String word){ int length = word.length(); char[] letters = new char[length]; for (int i = 0; i < length; i++){ letters[i]=word.charAt(i); } char[] alphabet = new char[26]; String abc = "abcdefghijklmnopqrstuvwxyz"; for (int i = 0; i < 26; i++){ alphabet[i]=abc.charAt(i); } int[] numbers = new int[length]; int place = 0; for (int i = 0; i < length; i++){ for (int j = 0; j < 26; j++){ if (alphabet[j]==letters[i]){ numbers[place]=j+1; place++; } } } int hornered = numbers[0] * 32; for (int i = 1; i < numbers.length; i++){ hornered += numbers[i]; if (i == numbers.length -1){ return hornered; } hornered = hornered % 997; hornered *= 32; } return hornered; } public static String[] makeReserved (){ reserved[0] = "abstract"; reserved[1] = "assert"; reserved[2] = "boolean"; reserved[3] = "break"; reserved[4] = "byte"; reserved[5] = "case"; reserved[6] = "catch"; reserved[7] = "char"; reserved[8] = "class"; reserved[9] = "const"; reserved[10] = "continue"; reserved[11] = "default"; reserved[12] = "do"; reserved[13] = "double"; reserved[14] = "else"; reserved[15] = "enum"; reserved[16] = "extends"; reserved[17] = "false"; reserved[18] = "final"; reserved[19] = "finally"; reserved[20] = "float"; reserved[21] = "for"; reserved[22] = "goto"; reserved[23] = "if"; reserved[24] = "implements"; reserved[25] = "import"; reserved[26] = "instanceof"; reserved[27] = "int"; reserved[28] = "interface"; reserved[29] = "long"; reserved[30] = "native"; reserved[31] = "new"; reserved[32] = "null"; reserved[33] = "package"; reserved[34] = "private"; reserved[35] = "protected"; reserved[36] = "public"; reserved[37] = "return"; reserved[38] = "short"; reserved[39] = "static"; reserved[40] = "strictfp"; reserved[41] = "super"; reserved[42] = "switch"; reserved[43] = "synchronize"; reserved[44] = "this"; reserved[45] = "throw"; reserved[46] = "throws"; reserved[47] = "trasient"; reserved[48] = "true"; reserved[49] = "try"; reserved[50] = "void"; reserved[51] = "volatile"; reserved[52] = "while"; reserved[53] = "="; reserved[54] = "=="; reserved[55] = "!="; reserved[56] = "+"; reserved[57] = "-"; reserved[58] = "*"; reserved[59] = "/"; reserved[60] = "{"; reserved[61] = "}"; return reserved; } }

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  • Null-free "maps": Is a callback solution slower than tryGet()?

    - by David Moles
    In comments to "How to implement List, Set, and Map in null free design?", Steven Sudit and I got into a discussion about using a callback, with handlers for "found" and "not found" situations, vs. a tryGet() method, taking an out parameter and returning a boolean indicating whether the out parameter had been populated. Steven maintained that the callback approach was more complex and almost certain to be slower; I maintained that the complexity was no greater and the performance at worst the same. But code speaks louder than words, so I thought I'd implement both and see what I got. The original question was fairly theoretical with regard to language ("And for argument sake, let's say this language don't even have null") -- I've used Java here because that's what I've got handy. Java doesn't have out parameters, but it doesn't have first-class functions either, so style-wise, it should suck equally for both approaches. (Digression: As far as complexity goes: I like the callback design because it inherently forces the user of the API to handle both cases, whereas the tryGet() design requires callers to perform their own boilerplate conditional check, which they could forget or get wrong. But having now implemented both, I can see why the tryGet() design looks simpler, at least in the short term.) First, the callback example: class CallbackMap<K, V> { private final Map<K, V> backingMap; public CallbackMap(Map<K, V> backingMap) { this.backingMap = backingMap; } void lookup(K key, Callback<K, V> handler) { V val = backingMap.get(key); if (val == null) { handler.handleMissing(key); } else { handler.handleFound(key, val); } } } interface Callback<K, V> { void handleFound(K key, V value); void handleMissing(K key); } class CallbackExample { private final Map<String, String> map; private final List<String> found; private final List<String> missing; private Callback<String, String> handler; public CallbackExample(Map<String, String> map) { this.map = map; found = new ArrayList<String>(map.size()); missing = new ArrayList<String>(map.size()); handler = new Callback<String, String>() { public void handleFound(String key, String value) { found.add(key + ": " + value); } public void handleMissing(String key) { missing.add(key); } }; } void test() { CallbackMap<String, String> cbMap = new CallbackMap<String, String>(map); for (int i = 0, count = map.size(); i < count; i++) { String key = "key" + i; cbMap.lookup(key, handler); } System.out.println(found.size() + " found"); System.out.println(missing.size() + " missing"); } } Now, the tryGet() example -- as best I understand the pattern (and I might well be wrong): class TryGetMap<K, V> { private final Map<K, V> backingMap; public TryGetMap(Map<K, V> backingMap) { this.backingMap = backingMap; } boolean tryGet(K key, OutParameter<V> valueParam) { V val = backingMap.get(key); if (val == null) { return false; } valueParam.value = val; return true; } } class OutParameter<V> { V value; } class TryGetExample { private final Map<String, String> map; private final List<String> found; private final List<String> missing; public TryGetExample(Map<String, String> map) { this.map = map; found = new ArrayList<String>(map.size()); missing = new ArrayList<String>(map.size()); } void test() { TryGetMap<String, String> tgMap = new TryGetMap<String, String>(map); for (int i = 0, count = map.size(); i < count; i++) { String key = "key" + i; OutParameter<String> out = new OutParameter<String>(); if (tgMap.tryGet(key, out)) { found.add(key + ": " + out.value); } else { missing.add(key); } } System.out.println(found.size() + " found"); System.out.println(missing.size() + " missing"); } } And finally, the performance test code: public static void main(String[] args) { int size = 200000; Map<String, String> map = new HashMap<String, String>(); for (int i = 0; i < size; i++) { String val = (i % 5 == 0) ? null : "value" + i; map.put("key" + i, val); } long totalCallback = 0; long totalTryGet = 0; int iterations = 20; for (int i = 0; i < iterations; i++) { { TryGetExample tryGet = new TryGetExample(map); long tryGetStart = System.currentTimeMillis(); tryGet.test(); totalTryGet += (System.currentTimeMillis() - tryGetStart); } System.gc(); { CallbackExample callback = new CallbackExample(map); long callbackStart = System.currentTimeMillis(); callback.test(); totalCallback += (System.currentTimeMillis() - callbackStart); } System.gc(); } System.out.println("Avg. callback: " + (totalCallback / iterations)); System.out.println("Avg. tryGet(): " + (totalTryGet / iterations)); } On my first attempt, I got 50% worse performance for callback than for tryGet(), which really surprised me. But, on a hunch, I added some garbage collection, and the performance penalty vanished. This fits with my instinct, which is that we're basically talking about taking the same number of method calls, conditional checks, etc. and rearranging them. But then, I wrote the code, so I might well have written a suboptimal or subconsicously penalized tryGet() implementation. Thoughts?

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  • Use a single freemarker template to display tables of arbitrary pojos

    - by Kevin Pauli
    Attention advanced Freemarker gurus: I want to use a single freemarker template to be able to output tables of arbitrary pojos, with the columns to display defined separately than the data. The problem is that I can't figure out how to get a handle to a function on a pojo at runtime, and then have freemarker invoke that function (lambda style). From skimming the docs it seems that Freemarker supports functional programming, but I can't seem to forumulate the proper incantation. I whipped up a simplistic concrete example. Let's say I have two lists: a list of people with a firstName and lastName, and a list of cars with a make and model. would like to output these two tables: <table> <tr> <th>firstName</th> <th>lastName</th> </tr> <tr> <td>Joe</td> <td>Blow</d> </tr> <tr> <td>Mary</td> <td>Jane</d> </tr> </table> and <table> <tr> <th>make</th> <th>model</th> </tr> <tr> <td>Toyota</td> <td>Tundra</d> </tr> <tr> <td>Honda</td> <td>Odyssey</d> </tr> </table> But I want to use the same template, since this is part of a framework that has to deal with dozens of different pojo types. Given the following code: public class FreemarkerTest { public static class Table { private final List<Column> columns = new ArrayList<Column>(); public Table(Column[] columns) { this.columns.addAll(Arrays.asList(columns)); } public List<Column> getColumns() { return columns; } } public static class Column { private final String name; public Column(String name) { this.name = name; } public String getName() { return name; } } public static class Person { private final String firstName; private final String lastName; public Person(String firstName, String lastName) { this.firstName = firstName; this.lastName = lastName; } public String getFirstName() { return firstName; } public String getLastName() { return lastName; } } public static class Car { String make; String model; public Car(String make, String model) { this.make = make; this.model = model; } public String getMake() { return make; } public String getModel() { return model; } } public static void main(String[] args) throws Exception { final Table personTableDefinition = new Table(new Column[] { new Column("firstName"), new Column("lastName") }); final List<Person> people = Arrays.asList(new Person[] { new Person("Joe", "Blow"), new Person("Mary", "Jane") }); final Table carTable = new Table(new Column[] { new Column("make"), new Column("model") }); final List<Car> cars = Arrays.asList(new Car[] { new Car("Toyota", "Tundra"), new Car("Honda", "Odyssey") }); final Configuration cfg = new Configuration(); cfg.setClassForTemplateLoading(FreemarkerTest.class, ""); cfg.setObjectWrapper(new DefaultObjectWrapper()); final Template template = cfg.getTemplate("test.ftl"); process(template, personTableDefinition, people); process(template, carTable, cars); } private static void process(Template template, Table tableDefinition, List<? extends Object> data) throws Exception { final Map<String, Object> dataMap = new HashMap<String, Object>(); dataMap.put("tableDefinition", tableDefinition); dataMap.put("data", data); final Writer out = new OutputStreamWriter(System.out); template.process(dataMap, out); out.flush(); } } All the above is a given for this problem. So here is the template I have been hacking on. Note the comment where I am having trouble. <table> <tr> <#list tableDefinition.columns as col> <th>${col.name}</th> </#list> </tr> <#list data as pojo> <tr> <#list tableDefinition.columns as col> <td><#-- what goes here? --></td> </#list> </tr> </#list> </table> So col.name has the name of the property I want to access from the pojo. I have tried a few things, such as pojo.col.name and <#assign property = col.name/> ${pojo.property} but of course these don't work, I just included them to help convey my intent. I am looking for a way to get a handle to a function and have freemarker invoke it, or perhaps some kind of "evaluate" feature that can take an arbitrary expression as a string and evaluate it at runtime.

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  • Producer and Consumer Threads Hang

    - by user972425
    So this is my first foray into threads and thus far it is driving me insane. My problem seems to be some kind of synchronization error that causes my consumer thread to hang. I've looked at other code and just about everything I could find and I can't find what my error is. There also seems to be a discrepancy between the code being executed in Eclipse and via javac in the command line. Intention - Using a bounded buffer (with 1000 slots) create and consume 1,000,000 doubles. Use only notify and wait. Problem - In Eclipse the consumer thread will occasionally hang around 940,000 iterations, but other times completes. In the command line the consumer thread always hangs. Output - Eclipse - Successful Producer has produced 100000 doubles. Consumer has consumed 100000 doubles. Producer has produced 200000 doubles. Consumer has consumed 200000 doubles. Producer has produced 300000 doubles. Consumer has consumed 300000 doubles. Producer has produced 400000 doubles. Consumer has consumed 400000 doubles. Producer has produced 500000 doubles. Consumer has consumed 500000 doubles. Producer has produced 600000 doubles. Consumer has consumed 600000 doubles. Producer has produced 700000 doubles. Consumer has consumed 700000 doubles. Producer has produced 800000 doubles. Consumer has consumed 800000 doubles. Producer has produced 900000 doubles. Consumer has consumed 900000 doubles. Producer has produced 1000000 doubles. Producer has produced all items. Consumer has consumed 1000000 doubles. Consumer has consumed all items. Exitting Output - Command Line/Eclipse - Unsuccessful Producer has produced 100000 doubles. Consumer has consumed 100000 doubles. Producer has produced 200000 doubles. Consumer has consumed 200000 doubles. Producer has produced 300000 doubles. Consumer has consumed 300000 doubles. Producer has produced 400000 doubles. Consumer has consumed 400000 doubles. Producer has produced 500000 doubles. Consumer has consumed 500000 doubles. Producer has produced 600000 doubles. Consumer has consumed 600000 doubles. Producer has produced 700000 doubles. Consumer has consumed 700000 doubles. Producer has produced 800000 doubles. Consumer has consumed 800000 doubles. Producer has produced 900000 doubles. Consumer has consumed 900000 doubles. Producer has produced 1000000 doubles. Producer has produced all items. At this point it just sits and hangs. Any help you can provide about where I might have misstepped is greatly appreciated. Code - Producer thread import java.text.DecimalFormat;+ " doubles. Cumulative value of generated items= " + temp) import java.util.*; import java.io.*; public class producer implements Runnable{ private buffer produceBuff; public producer (buffer buff){ produceBuff = buff; } public void run(){ Random random = new Random(); double temp = 0, randomElem; DecimalFormat df = new DecimalFormat("#.###"); for(int i = 1; i<=1000000; i++) { randomElem = (Double.parseDouble( df.format(random.nextDouble() * 100.0))); try { produceBuff.add(randomElem); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } temp+= randomElem; if(i%100000 == 0) {produceBuff.print("Producer has produced "+ i ); } } produceBuff.print("Producer has produced all items."); } } Consumer thread import java.util.*; import java.io.*; public class consumer implements Runnable{ private buffer consumBuff; public consumer (buffer buff){ consumBuff = buff; } public void run(){ double temp = 0; for(int i = 1; i<=1000000; i++) { try { temp += consumBuff.get(); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } if(i%100000 == 0) {consumBuff.print("Consumer has consumed "+ i ); //if(i>999000) //{System.out.println("Consuming item " + i);} } consumBuff.print("Consumer has consumed all items."); } } Buffer/Main import java.util.*; import java.io.*; public class buffer { private double buff[]; private int addPlace; private int getPlace; public buffer(){ buff = new double[1000]; addPlace = 0; getPlace = 0; } public synchronized void add(double add) throws InterruptedException{ if((addPlace+1 == getPlace) ) { try { wait(); } catch (InterruptedException e) {throw e;} } buff[addPlace] = add; addPlace = (addPlace+1)%1000; notify(); } public synchronized double get()throws InterruptedException{ if(getPlace == addPlace) { try { wait(); } catch (InterruptedException e) {throw e;} } double temp = buff[getPlace]; getPlace = (getPlace+1)%1000; notify(); return temp; } public synchronized void print(String view) { System.out.println(view); } public static void main(String args[]){ buffer buf = new buffer(); Thread produce = new Thread(new producer(buf)); Thread consume = new Thread(new consumer(buf)); produce.start(); consume.start(); try { produce.join(); consume.join(); } catch (InterruptedException e) {return;} System.out.println("Exitting"); } }

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  • C++/CLI HTTP Proxy problems...

    - by darkantimatter
    Hi, I'm trying(very hard) to make a small HTTP Proxy server which I can use to save all communications to a file. Seeing as I dont really have any experience in the area, I used a class from codeproject.com and some associated code to get started (It was made in the old CLI syntax, so I converted it). I couldn't get it working, so I added lots more code to make it work (threads etc), and now it sort of works. Basically, it recieves something from a client (I just configured Mozilla Firefox to route its connections through this proxy) and then routes it to google.com. After it sends Mozilla's data to google, recieves a responce, and sends that to Mozilla. This works fine, but then the proxy fails to recieve any data from Mozilla. It just loops in the Sleep(50) section. Anyway, heres the code: ProxyTest.cpp: #include "stdafx.h" #include "windows.h" #include "CHTTPProxy.h" public ref class ClientThread { public: System::Net::Sockets::TcpClient ^ pClient; CHttpProxy ^ pProxy; System::Int32 ^ pRecieveBufferSize; System::Threading::Thread ^ Thread; ClientThread(System::Net::Sockets::TcpClient ^ sClient, CHttpProxy ^ sProxy, System::Int32 ^ sRecieveBufferSize) { pClient = sClient; pProxy = sProxy; pRecieveBufferSize = sRecieveBufferSize; }; void StartReading() { Thread = gcnew System::Threading::Thread(gcnew System::Threading::ThreadStart(this,&ClientThread::ThreadEntryPoint)); Thread->Start(); }; void ThreadEntryPoint() { char * bytess; bytess = new char[(int)pRecieveBufferSize]; memset(bytess, 0, (int)pRecieveBufferSize); array<unsigned char> ^ bytes = gcnew array<unsigned char>((int)pRecieveBufferSize); array<unsigned char> ^ sendbytes; do { if (pClient->GetStream()->DataAvailable) { try { do { Sleep(100); //Lets wait for whole packet to get cached (If it even does...) unsigned int k = pClient->GetStream()->Read(bytes, 0, (int)pRecieveBufferSize); //Read it for(unsigned int i=0; i<(int)pRecieveBufferSize; i++) bytess[i] = bytes[i]; Console::WriteLine("Packet Received:\n"+gcnew System::String(bytess)); pProxy->SendToServer(bytes,pClient->GetStream()); //Now send it to google! pClient->GetStream()->Flush(); } while(pClient->GetStream()->DataAvailable); } catch (Exception ^ e) { break; } } else { Sleep(50); //It just loops here because it thinks mozilla isnt sending anything if (!(pClient->Connected)) break; }; } while (pClient->GetStream()->CanRead); delete [] bytess; pClient->Close(); }; }; int main(array<System::String ^> ^args) { System::Collections::Generic::Stack<ClientThread ^> ^ Clients = gcnew System::Collections::Generic::Stack<ClientThread ^>(); System::Net::Sockets::TcpListener ^ pTcpListener = gcnew System::Net::Sockets::TcpListener(8080); pTcpListener->Start(); System::Net::Sockets::TcpClient ^ pTcpClient; while (1) { pTcpClient = pTcpListener->AcceptTcpClient(); //Wait for client ClientThread ^ Client = gcnew ClientThread(pTcpClient, gcnew CHttpProxy("www.google.com.au", 80), pTcpClient->ReceiveBufferSize); //Make a new object for this client Client->StartReading(); //Start the thread Clients->Push(Client); //Add it to the list }; pTcpListener->Stop(); return 0; } CHTTPProxy.h, from http://www.codeproject.com/KB/IP/howtoproxy.aspx with a lot of modifications: //THIS FILE IS FROM http://www.codeproject.com/KB/IP/howtoproxy.aspx. I DID NOT MAKE THIS! BUT I HAVE MADE SEVERAL MODIFICATIONS! #using <mscorlib.dll> #using <SYSTEM.DLL> using namespace System; using System::Net::Sockets::TcpClient; using System::String; using System::Exception; using System::Net::Sockets::NetworkStream; #include <stdio.h> ref class CHttpProxy { public: CHttpProxy(System::String ^ szHost, int port); System::String ^ m_host; int m_port; void SendToServer(array<unsigned char> ^ Packet, System::Net::Sockets::NetworkStream ^ sendstr); }; CHttpProxy::CHttpProxy(System::String ^ szHost, int port) { m_host = gcnew System::String(szHost); m_port = port; } void CHttpProxy::SendToServer(array<unsigned char> ^ Packet, System::Net::Sockets::NetworkStream ^ sendstr) { TcpClient ^ tcpclnt = gcnew TcpClient(); try { tcpclnt->Connect(m_host,m_port); } catch (Exception ^ e ) { Console::WriteLine(e->ToString()); return; } // Send it if ( tcpclnt ) { NetworkStream ^ networkStream; networkStream = tcpclnt->GetStream(); int size = Packet->Length; networkStream->Write(Packet, 0, size); array<unsigned char> ^ bytes = gcnew array<unsigned char>(tcpclnt->ReceiveBufferSize); char * bytess = new char[tcpclnt->ReceiveBufferSize]; Sleep(500); //Wait for responce do { unsigned int k = networkStream->Read(bytes, 0, (int)tcpclnt->ReceiveBufferSize); //Read from google for(unsigned int i=0; i<k; i++) { bytess[i] = bytes[i]; if (bytess[i] == 0) bytess[i] = ' '; //Dont terminate the string if (bytess[i] < 8) bytess[i] = ' '; //Somethings making the computer beep, and its not 7?!?! }; Console::WriteLine("\n\nAbove packet sent to google. Google Packet Received:\n"+gcnew System::String(bytess)); sendstr->Write(bytes,0,k); //Send it to mozilla Console::WriteLine("\n\nAbove packet sent to client..."); //Sleep(1000); } while(networkStream->DataAvailable); delete [] bytess; } return; } Any help would be much appreciated, I've tried for hours.

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  • How to convert this procedural programming to object-oriented programming?

    - by manus91
    I have a source code that is needed to be converted by creating classes, objects and methods. So far, I've just done by converting the initial main into a separate class. But I don't know what to do with constructor and which variables are supposed to be private. This is the code : import java.util.*; public class Card{ private static void shuffle(int[][] cards){ List<Integer> randoms = new ArrayList<Integer>(); Random randomizer = new Random(); for(int i = 0; i < 8;) { int r = randomizer.nextInt(8)+1; if(!randoms.contains(r)) { randoms.add(r); i++; } } List<Integer> clonedList = new ArrayList<Integer>(); clonedList.addAll(randoms); Collections.shuffle(clonedList); randoms.addAll(clonedList); Collections.shuffle(randoms); int i=0; for(int r=0; r < 4; r++){ for(int c=0; c < 4; c++){ cards[r][c] = randoms.get(i); i++; } } } public static void play() throws InterruptedException { int ans = 1; int preview; int r1,c1,r2,c2; int[][] cards = new int[4][4]; boolean[][] cardstatus = new boolean[4][4]; boolean gameover = false; int moves; Scanner input = new Scanner(System.in); do{ moves = 0; shuffle(cards); System.out.print("Enter the time(0 to 5) in seconds for the preview of the answer : "); preview = input.nextInt(); while((preview<0) || (preview>5)){ System.out.print("Invalid time!! Re-enter time(0 - 5) : "); preview = input.nextInt(); } preview = 1000*preview; System.out.println(" "); for (int i =0; i<4;i++){ for (int j=0;j<4;j++){ System.out.print(cards[i][j]); System.out.print(" "); } System.out.println(""); System.out.println(""); } Thread.sleep(preview); for(int b=0;b<25;b++){ System.out.println(" "); } for(int r=0;r<4;r++){ for(int c=0;c<4;c++){ System.out.print("*"); System.out.print(" "); cardstatus[r][c] = false; } System.out.println(""); System.out.println(" "); } System.out.println(""); do{ do{ System.out.print("Please insert the first card row : "); r1 = input.nextInt(); while((r1<1) || (r1>4)){ System.out.print("Invalid coordinate!! Re-enter first card row : "); r1 = input.nextInt(); } System.out.print("Please insert the first card column : "); c1 = input.nextInt(); while((c1<1) || (c1>4)){ System.out.print("Invalid coordinate!! Re-enter first card column : "); c1 = input.nextInt(); } if(cardstatus[r1-1][c1-1] == true){ System.out.println("The card is already flipped!! Select another card."); System.out.println(""); } }while(cardstatus[r1-1][c1-1] != false); do{ System.out.print("Please insert the second card row : "); r2 = input.nextInt(); while((r2<1) || (r2>4)){ System.out.print("Invalid coordinate!! Re-enter second card row : "); r2 = input.nextInt(); } System.out.print("Please insert the second card column : "); c2 = input.nextInt(); while((c2<1) || (c2>4)){ System.out.print("Invalid coordinate!! Re-enter second card column : "); c2 = input.nextInt(); } if(cardstatus[r2-1][c2-1] == true){ System.out.println("The card is already flipped!! Select another card."); } if((r1==r2)&&(c1==c2)){ System.out.println("You can't select the same card twice!!"); continue; } }while(cardstatus[r2-1][c2-1] != false); r1--; c1--; r2--; c2--; System.out.println(""); System.out.println(""); System.out.println(""); for(int r=0;r<4;r++){ for(int c=0;c<4;c++){ if((r==r1)&&(c==c1)){ System.out.print(cards[r][c]); System.out.print(" "); } else if((r==r2)&&(c==c2)){ System.out.print(cards[r][c]); System.out.print(" "); } else if(cardstatus[r][c] == true){ System.out.print(cards[r][c]); System.out.print(" "); } else{ System.out.print("*"); System.out.print(" "); } } System.out.println(" "); System.out.println(" "); } System.out.println(""); if(cards[r1][c1] == cards[r2][c2]){ System.out.println("Cards Matched!!"); cardstatus[r1][c1] = true; cardstatus[r2][c2] = true; } else{ System.out.println("No cards match!!"); } Thread.sleep(2000); for(int b=0;b<25;b++){ System.out.println(""); } for(int r=0;r<4;r++){ for(int c=0;c<4;c++){ if(cardstatus[r][c] == true){ System.out.print(cards[r][c]); System.out.print(" "); } else{ System.out.print("*"); System.out.print(" "); } } System.out.println(""); System.out.println(" "); } System.out.println(""); System.out.println(""); System.out.println(""); gameover = true; for(int r=0;r<4;r++){ for( int c=0;c<4;c++){ if(cardstatus[r][c]==false){ gameover = false; break; } } if(gameover==false){ break; } } moves++; }while(gameover != true); System.out.println("Congratulations, you won!!"); System.out.println("It required " + moves + " moves to finish it."); System.out.println(""); System.out.print("Would you like to play again? (1=Yes / 0=No) : "); ans = input.nextInt(); }while(ans == 1); } } The main class is: import java.util.*; public class PlayCard{ public static void main(String[] args) throws InterruptedException{ Card game = new Card(); game.play(); } } Should I simplify the Card class by creating other classes? Through this code, my javadoc has no constructtor. So i need help on this!

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  • Help with java GUI- has error in main thread

    - by jan
    Hello guys, Basically im trying to do a Insurance Application form in java. And it uses multiple JPanels in a JFrame. -adding of JPanel into main program frame was done like this: //jpCenterArea to hold jp1-jp7 jpCenterArea.add(jp1); jpCenterArea.add(jp2); jpCenterArea.add(jp3); jpCenterArea.add(jp4); ...etc ********Add Jpanels to JFrame*****/ add(jpTitle, BorderLayout.NORTH); add(jpCenterArea, BorderLayout.CENTER); add(jpBottom, BorderLayout.SOUTH); However, even though program can compile, it cannot be run. error as mentioned below: Exception in thread "main" java.lang.NullPointerException at java.awt.Container.addImpl<Container.java:1045> at java.awt.Container.add<Container.java:365> at TravelInsuranceApplication.<init>TravelInsuranceApplication.java:120> at TravelInsuranceApplication.main<TravelInsuranceApplication.java:154> 1 import javax.swing.*; 2 import java.awt.*; 3 public class TravelInsuranceApplication extends JFrame 4 { 5 //declare private variables 6 private JLabel jlblTitle, jlblName, jlblNRIC, jlblAdd, jlblPostal, jlblContact, jlblDOB, 7 jlblEmail, jlblPeriod; 8 private JLabel jlblDeparture, jlblDays, jlblZone, jlblPlan; 9 private JTextField jtfName, jtfIC, jtfAdd, jtfPostal, jtfContact, jtfEmail, jtfZone; 10 private JRadioButton jrbResident, jrbOffice, jrbDeluxe, jrbClassic, jrbAsia, jrbWorldwide; 11 private ButtonGroup bgContact, bgZone, bgPlan; 12 private JComboBox jcDay, jcMonth, jcYear; 13 private JButton jbtnSubmit, jbtnCalculate, jbtnClear; 14 private JPanel jpTitle,jp1, jp2, jp3, jp4, jp5, jp6, jp7, jpBottom, jpCenterArea; 15 String[] day = {"1", "2", "3"}; 16 String[] month = {"january", "february"}; 17 String[] year = {"1981", "1985", "1990", "1995"}; 18 19 //constructor and GUI development 20 public TravelInsuranceApplication() 21 { 22 setSize(500,200); 23 setTitle("Travel Insurance Application"); 24 setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 25 setLayout(new BorderLayout()); 26 27 //create ALL component objects/ 28 jlblTitle = new JLabel("Travel Insurance Application: "); 29 jlblName = new JLabel("Name of Insured: "); 30 jlblNRIC = new JLabel("NRIC: "); 31 jlblAdd = new JLabel("Address: "); 32 jlblPostal = new JLabel("Postal Code: "); 33 jlblContact = new JLabel("Telephone: "); 34 jlblDOB = new JLabel("Date Of Birth: "); 35 jlblEmail = new JLabel("Email Address: "); 36 jlblPeriod = new JLabel("Period Of Insurance "); 37 jlblDeparture = new JLabel("Departure Date "); 38 jlblDays = new JLabel("How Many Days To Insure "); 39 jlblZone = new JLabel("Zone: "); 40 jlblPlan = new JLabel("Plan: "); 41 42 jtfName = new JTextField(50); 43 jtfIC = new JTextField(15); 44 jtfAdd = new JTextField(50); 45 jtfPostal = new JTextField(15); 46 jtfContact = new JTextField(15); 47 jtfEmail = new JTextField(50); 48 jtfZone = new JTextField(100); 49 50 jrbResident = new JRadioButton("Rseident/Pgr"); 51 jrbOffice = new JRadioButton("Office/HP"); 52 jrbAsia = new JRadioButton("Asia"); 53 jrbAsia = new JRadioButton("Worldwide"); 54 jrbDeluxe = new JRadioButton("Deluxe"); 55 jrbClassic = new JRadioButton("Classic"); 56 57 jcDay = new JComboBox(day); 58 jcMonth = new JComboBox(month); 59 jcYear = new JComboBox(year); 60 61 jbtnSubmit = new JButton("Submit"); 62 jbtnCalculate = new JButton("Calculate"); 63 jbtnClear = new JButton("Clear"); 64 65 /****create JPanels - jpTitle, JpCenterArea & jp2-jp8 , jpBottom + setLayout 66 for ALL JPanels******/ 67 jpTitle = new JPanel(new FlowLayout(FlowLayout.CENTER)); 68 jpCenterArea = new JPanel(new FlowLayout()); 69 jp1 = new JPanel(new FlowLayout()); 70 jp2 = new JPanel(new FlowLayout(FlowLayout.CENTER)); 71 jp3 = new JPanel(new FlowLayout()); 72 jp4 = new JPanel(new FlowLayout()); 73 jp5 = new JPanel(new FlowLayout()); 74 jp6 = new JPanel(new FlowLayout(FlowLayout.CENTER)); 75 jp7 = new JPanel(new FlowLayout(FlowLayout.CENTER)); 76 jpBottom = new JPanel(new FlowLayout(FlowLayout.CENTER)); 77 78 79 80 81 //add components to JPanels 82 jpTitle.add(jlblTitle); 83 84 //jp1 85 jp1.add(jlblName); 86 jp1.add(jtfName); 87 jp1.add(jlblNRIC); 88 jp1.add(jtfIC); 89 90 //jp2 91 jp2.add(jlblAdd); 92 jp2.add(jtfAdd); 93 jp2.add(jlblPostal); 94 jp2.add(jtfPostal); 95 96 //jp3 97 jp3.add(jlblContact); 98 jp3.add(jtfContact); 99 jp3.add(jrbResident); 100 jp3.add(jrbOffice); 101 jp3.add(jlblDOB); 102 jp3.add(jcDay); 103 jp3.add(jcMonth); 104 jp3.add(jcYear); 105 106 //jp4 107 jp4.add(jlblEmail); 108 jp4.add(jtfEmail); 109 110 //jp5 111 jp5.add(jlblPeriod); 112 jp5.add(jlblDeparture); 113 jp5.add(jcDay); 114 jp5.add(jcMonth); 115 jp5.add(jcYear); 116 jp5.add(jlblDays); 117 jp5.add(jcDay); 118 119 //jp6 120 jp6.add(jlblZone); 121 jp6.add(jrbAsia); 122 jp6.add(jrbWorldwide); 123 jp6.add(jlblPlan); 124 jp6.add(jrbDeluxe); 125 jp6.add(jrbClassic); 126 127 //jp7 128 jp7.add(jtfZone); 129 130 //jpCenterArea to hold jp1-jp7 131 jpCenterArea.add(jp1); 132 jpCenterArea.add(jp2); 133 jpCenterArea.add(jp3); 134 jpCenterArea.add(jp4); 135 jpCenterArea.add(jp5); 136 jpCenterArea.add(jp6); 137 jpCenterArea.add(jp7); 138 139 //jpBottom 140 jpBottom.add(jbtnSubmit); 141 jpBottom.add(jbtnCalculate); 142 jpBottom.add(jbtnClear); 143 144 /********Add Jpanels to JFrame*****/ 145 add(jpTitle, BorderLayout.NORTH); 146 add(jpCenterArea, BorderLayout.CENTER); 147 add(jpBottom, BorderLayout.SOUTH); 148 149 setVisible(true); 150 151 152 153 }//end null constructor 154 public static void main(String[] args) 155 { 156 TravelInsuranceApplication travel = new TravelInsuranceApplication(); 157 158 }//end main 159 160 }//end class

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  • how to display bitmaps in listview?

    - by mary
    hi i want to show images downloaded in listview.images downloaded with function DownloadImage and are as bitmap.how to show in listview . name photoes with book_id in tabel book are aqual.i want each book has its own image. i can show in listview book_name and book_price just the problem with image book please help me class: package bookstore.category; import java.io.IOException; import java.io.InputStream; import java.net.HttpURLConnection; import java.net.URL; import java.net.URLConnection; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import org.apache.http.NameValuePair; import org.json.JSONArray; import org.json.JSONException; import org.json.JSONObject; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.graphics.Typeface; import android.os.AsyncTask; import android.os.Bundle; import android.util.Log; import android.widget.ImageView; import android.widget.ListAdapter; import android.widget.ListView; import android.widget.SimpleAdapter; import bookstore.pack.JSONParser; import bookstore.pack.R; import android.app.Activity; import android.app.ProgressDialog; public class Computer extends Activity { Bitmap bm = null; // progress dialog private ProgressDialog pDialog; // Creating JSON Parser object JSONParser jParser = new JSONParser(); ArrayList<HashMap<String, String>> computerBookList; private static String url_books = "http://10.0.2.2/project/computer.php"; // JSON Node names private static final String TAG_SUCCESS = "success"; private static final String TAG_BOOK = "book"; private static final String TAG_BOOK_NAME = "book_name"; private static final String TAG_BOOK_PRICE = "book_price"; private static final String TAG_BOOK_ID = "book_id"; private static final String TAG_MESSAGE = "massage"; // category JSONArray JSONArray book = null; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.category); Typeface font1 = Typeface.createFromAsset(getAssets(), "font/bnazanin.TTF"); // Hashmap for ListView computerBookList = new ArrayList<HashMap<String, String>>(); new LoadBook().execute(); } class LoadBook extends AsyncTask<String, String, String> { /** * Before starting background thread Show Progress Dialog * */ @Override protected void onPreExecute() { super.onPreExecute(); pDialog = new ProgressDialog(Computer.this); pDialog.setMessage("Please wait..."); pDialog.setIndeterminate(false); pDialog.setCancelable(false); pDialog.show(); } protected String doInBackground(String... args) { // Building Parameters List<NameValuePair> params = new ArrayList<NameValuePair>(); // getting JSON string from URL JSONObject json = jParser.makeHttpRequest(url_books, "GET", params); // Check your log cat for JSON reponse Log.d("book:", json.toString()); try { // Checking for SUCCESS TAG int success = json.getInt(TAG_SUCCESS); if (success == 1) { DownloadImage("10.0.2.2/project/images/100.png"); DownloadImage("10.0.2.2/project/images/101.png"); DownloadImage("10.0.2.2/project/images/102.png"); DownloadImage("10.0.2.2/project/images/103.png"); DownloadImage("10.0.2.2/project/images/104.png"); DownloadImage("10.0.2.2/project/images/105.png"); DownloadImage("10.0.2.2/project/images/106.png"); DownloadImage("10.0.2.2/project/images/107.png"); DownloadImage("10.0.2.2/project/images/108.png"); DownloadImage("10.0.2.2/project/images/109.png"); DownloadImage("10.0.2.2/project/images/110.png"); // books found book = json.getJSONArray(TAG_BOOK); for (int i = 0; i < book.length(); i++) { JSONObject c = book.getJSONObject(i); // Storing each json item in variable String book_name = c.getString(TAG_BOOK_NAME); String book_price = c.getString(TAG_BOOK_PRICE); String book_id = c.getString(TAG_BOOK_ID); // creating new HashMap HashMap<String, String> map = new HashMap<String, String>(); // adding each child node to HashMap key => value map.put(TAG_BOOK_NAME, book_name); map.put(TAG_BOOK_PRICE, book_price); // map.put(TAG_AUTHOR_NAME, author_name); // adding HashList to ArrayList computerBookList.add(map); } return json.getString(TAG_MESSAGE); } else { System.out.println("no book found"); } } catch (JSONException e) { e.printStackTrace(); } return null; } /** * After completing background task Dismiss the progress dialog * **/ protected void onPostExecute(String file_url) { pDialog.dismiss(); // updating UI from Background Thread runOnUiThread(new Runnable() { ListView view1 = (ListView) findViewById(R.id.list_view); public void run() { ImageView iv = (ImageView) findViewById(R.id.list_image); // bm=BitmapFactory.decodeResource(getResources(), resId); //bm=BitmapFactory.decodeResource(null,R.id.list_image); // iv.setImageBitmap(bm); /* * */ /** * Updating parsed JSON data into ListView * */ ListAdapter adapter = new SimpleAdapter(Computer.this, computerBookList, R.layout.search_item, new String[] { TAG_BOOK_NAME, TAG_BOOK_PRICE }, new int[] { R.id.book_name, R.id.book_price }); view1.setAdapter(adapter); } }); } } private Bitmap DownloadImage(String URL) { Bitmap bitmap = null; InputStream in = null; try { in = OpenHttpConnection(URL); bitmap = BitmapFactory.decodeStream(in); in.close(); } catch (IOException e1) { e1.printStackTrace(); } return bitmap; } private InputStream OpenHttpConnection(String urlString) throws IOException { InputStream in = null; int response = -1; URL url = new URL(urlString); URLConnection conn = url.openConnection(); if (!(conn instanceof HttpURLConnection)) throw new IOException("Not an HTTP connection"); try { HttpURLConnection httpConn = (HttpURLConnection) conn; httpConn.setAllowUserInteraction(false); httpConn.setInstanceFollowRedirects(true); httpConn.setRequestMethod("GET"); httpConn.connect(); response = httpConn.getResponseCode(); if (response == HttpURLConnection.HTTP_OK) { in = httpConn.getInputStream(); } } catch (Exception ex) { throw new IOException("Error connecting"); } return in; } }

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  • Ladder word-like game GUI problems

    - by sasquatch90
    Ok so I've written my own version of game which should look like this : http://img199.imageshack.us/img199/6859/lab9a.jpg but mine looks like that : http://img444.imageshack.us/img444/7671/98921674.jpg How can I fix this ? Is there a way to do the layout completely differently ? Here's the code : Main.java : import java.util.Scanner; import javax.swing.*; import java.awt.*; public class Main { public static void main(String[] args){ final JFrame f = new JFrame("Ladder Game"); Scanner sc = new Scanner(System.in); System.out.println("Creating game data..."); System.out.println("Height: "); while (!sc.hasNextInt()) { System.out.println("int, please!"); sc.next(); } final int height = sc.nextInt(); Grid[]game = new Grid[height]; for(int L = 0; L < height; L++){ Grid row = null; int i = L+1; String s; do { System.out.println("Length "+i+", please!"); s = sc.next(); } while (s.length() != i); Element[] line = new Element[s.length()]; Element single = null; String[] temp = null; String[] temp2 = new String[s.length()]; temp = s.split(""); for( int j = temp2.length; j>0; j--){ temp2[j-1] = temp[j]; } for (int k = 0 ; k < temp2.length ; k++) { if( k == 0 ){ single = new Element(temp2[k], 2); } else{ single = new Element(temp2[k], 1); } line[k] = single; } row = new Grid(line); game[L] = row; } //############################################ //THE GAME STARTS HERE //############################################ JPanel panel = new JPanel(); panel.setLayout(new BoxLayout(panel, BoxLayout.X_AXIS)); panel.setBackground(Color.ORANGE); panel.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10)); for(int i = 0; i < game.length; i++){ panel.add(game[i].create()); } f.setContentPane(panel); f.pack(); f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); f.setVisible(true); boolean end = false; boolean word = false; String tekst; while( !end ){ while( !word ){ tekst = JOptionPane.showInputDialog("Input word: "); for(int i = 0; i< game.length; i++){ if(game[i].equalLength(tekst)){ if(game[i].equalValue(tekst)){ word = true; for(int j = 0; j< game.length; j++){ game[i].repaint(); } } } } } word = false; for(int i = 0; i < game.length; i++){ if(game[i].solved()){ end = true; } else { end = false; } } } } } Grid.java import javax.swing.*; import java.awt.*; public class Grid extends JPanel{ private Element[]e; private Grid[]g; public Grid(){} public Grid( Element[]elements ){ e = new Element[elements.length]; for(int i=0; i< e.length; i++){ e[i] = elements[i]; } } public Grid(Grid[]grid){ g = new Grid[grid.length]; for(int i=0; i<g.length; i++){ g[i] = grid[i]; } Dimension d = new Dimension(600, 600); setMinimumSize(d); setPreferredSize(new Dimension(d)); setMaximumSize(d); } public JPanel create(){ JPanel panel = new JPanel(); panel.setLayout(new BoxLayout(panel, BoxLayout.PAGE_AXIS)); panel.setBorder(BorderFactory.createEmptyBorder(2, 2, 2, 2)); for(int j = 0; j < e.length; j++){ panel.add(e[j].paint()); } return panel; } @Override public void repaint(){ } public boolean equalLength(String s){ int len = s.length(); boolean equal = false; for(int j = 0; j < e.length; j++){ if(e.length == len){ equal = true; } } return equal; } public boolean equalValue(String s){ int len = s.length(); boolean equal = false; String[] temp = null; String[] temp2 = new String[len]; temp = s.split(""); for( int j = len; j>0; j--){ temp2[j-1] = temp[j]; } for(int j = 0; j < e.length; j++){ if( e[j].letter().equals(temp2[j]) ){ equal = true; } else { equal = false; } } if(equal){ for(int i = 0; i < e.length; i++){ e[i].changeState(3); } } return equal; } public boolean solved(){ boolean solved = false; for(int j = 0; j < e.length; j++){ if(e[j].getState() == 3){ solved = true; } else { solved = false; } } return solved; } @Override public String toString(){ return ""; } } Element.java import javax.swing.*; import java.awt.*; public class Element { final int INVISIBLE = 0; final int EMPTY = 1; final int FIRST_LETTER = 2; final int OTHER_LETTER = 3; private int state; private String letter; public Element(){ } //empty block public Element(int state){ this("", 0); } //filled block public Element(String s, int state){ this.state = state; this.letter = s; } public JButton paint(){ JButton button = null; if( state == EMPTY ){ button = new JButton(""); button.setBackground(Color.WHITE); } else if ( state == FIRST_LETTER ){ button = new JButton(letter); button.setBackground(Color.red); } else { button = new JButton(letter); button.setBackground(Color.yellow); } button.setSize(20,20); return button; } public void changeState(int s){ state = s; } public String letter(){ return letter; } public int getState(){ return state; } @Override public String toString(){ return "["+letter+"]"; } }

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  • A "Trig" Calculating Class

    - by Clinton Scott
    I have been trying to create a gui that calculates trigonometric functions based off of the user's input. I have had success in the GUI part, but my class that I wrote to hold information using inheritance seems to be messed up, because when I run it gives an error saying: Exception in thread "main" java.lang.RuntimeException: Uncompilable source code - constructor ArcTrigCalcCon in class TrigCalc.ArcTrigCalcCon cannot be applied to given types; required: double,double,double,double,double,double found: java.lang.Double,java.lang.Double,java.lang.Double reason: actual and formal argument lists differ in length at TrigCalc.TrigCalcGUI.(TrigCalcGUI.java:31) at TrigCalc.TrigCalcGUI.main(TrigCalcGUI.java:87) Java Result: 1 and says it is the object causing the problem. Below Will be my code. First I will put up my inheritance class with cosecant secant and cotangent and then my original class with the original 3 trig functions: { public ArcTrigCalcCon(double s, double cs, double t, double csc, double sc, double ct) { // Inherit from the Trig Calc class super(s, cs, t); cosecant = 1/s; secant = 1/cs; cotangent = 1/t; } public void setCsc(double csc) { cosecant = csc; } public void setSec(double sc) { secant = sc; } public void setCot(double ct) { cotangent = ct; } } Here is the first Trigonometric class: public class TrigCalcCon { public double sine; public double cosine; public double tangent; public TrigCalcCon(double s, double cs, double t) { sine = s; cosine = cs; tangent = t; } public void setSin(double s) { sine = s; } public void setCos(double cs) { cosine = cs; } public void setTan(double t) { tangent = t; } public void set(double s, double cs, double t) { sine = s; cosine = cs; tangent = t; } public double getSin() { return Math.sin(sine); } public double getCos() { return Math.cos(cosine); } public double getTan() { return Math.tan(tangent); } } and here is the demo class to run the gui: public class TrigCalcGUI extends JFrame implements ActionListener { // Instance Variables private String input; private Double s, cs, t, csc, sc, ct; private JPanel mainPanel, sinPanel, cosPanel, tanPanel, cscPanel, secPanel, cotPanel, buttonPanel, inputPanel, displayPanel; // Panel Display private JLabel sinLabel, cosLabel, tanLabel, secLabel, cscLabel, cotLabel, inputLabel; private JTextField sinTF, cosTF, tanTF, secTF, cscTF, cotTF, inputTF; //Text Fields for sin, cos, and tan, and inverse private JButton calcButton, clearButton; // Calculate and Exit Buttons // Object ArcTrigCalcCon trC = new ArcTrigCalcCon(s, cs, t); public TrigCalcGUI() { // title bar text. super("Trig Calculator"); // Corner exit button action. setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); // Create main panel to add each panel to mainPanel = new JPanel(); mainPanel.setLayout(new GridLayout(3,2)); displayPanel = new JPanel(); displayPanel.setLayout(new GridLayout(3,2)); // Assign Panel to each variable inputPanel = new JPanel(); sinPanel = new JPanel(); cosPanel = new JPanel(); tanPanel = new JPanel(); cscPanel = new JPanel(); secPanel = new JPanel(); cotPanel = new JPanel(); buttonPanel = new JPanel(); // Call each constructor buildInputPanel(); buildSinCosTanPanels(); buildCscSecCotPanels(); buildButtonPanel(); // Add each panel to content pane displayPanel.add(sinPanel); displayPanel.add(cscPanel); displayPanel.add(cosPanel); displayPanel.add(secPanel); displayPanel.add(tanPanel); displayPanel.add(cotPanel); // Add three content panes to GUI mainPanel.add(inputPanel, BorderLayout.NORTH); mainPanel.add(displayPanel, BorderLayout.CENTER); mainPanel.add(buttonPanel, BorderLayout.SOUTH); //add mainPanel this.add(mainPanel); // size of window to content this.pack(); // display window setVisible(true); } public static void main(String[] args) { new TrigCalcGUI(); } private void buildInputPanel() { inputLabel = new JLabel("Enter a Value: "); inputTF = new JTextField(5); inputPanel.add(inputLabel); inputPanel.add(inputTF); } // Building Constructor for sinPanel cosPanel, and tanPanel private void buildSinCosTanPanels() { // Set layout and border for sinPanel sinPanel.setLayout(new GridLayout(2,2)); sinPanel.setBorder(BorderFactory.createTitledBorder("Sine")); // sinTF = new JTextField(5); sinTF.setEditable(false); sinPanel.add(sinTF); // Set layout and border for cosPanel cosPanel.setLayout(new GridLayout(2,2)); cosPanel.setBorder(BorderFactory.createTitledBorder("Cosine")); cosTF = new JTextField(5); cosTF.setEditable(false); cosPanel.add(cosTF); // Set layout and border for tanPanel tanPanel.setLayout(new GridLayout(2,2)); tanPanel.setBorder(BorderFactory.createTitledBorder("Tangent")); tanTF = new JTextField(5); tanTF.setEditable(false); tanPanel.add(tanTF); } // Building Constructor for cscPanel secPanel, and cotPanel private void buildCscSecCotPanels() { // Set layout and border for cscPanel cscPanel.setLayout(new GridLayout(2,2)); cscPanel.setBorder(BorderFactory.createTitledBorder("Cosecant")); // cscTF = new JTextField(5); cscTF.setEditable(false); cscPanel.add(cscTF); // Set layout and border for secPanel secPanel.setLayout(new GridLayout(2,2)); secPanel.setBorder(BorderFactory.createTitledBorder("Secant")); secTF = new JTextField(5); secTF.setEditable(false); secPanel.add(secTF); // Set layout and border for cotPanel cotPanel.setLayout(new GridLayout(2,2)); cotPanel.setBorder(BorderFactory.createTitledBorder("Cotangent")); cotTF = new JTextField(5); cotTF.setEditable(false); cotPanel.add(cotTF); } private void buildButtonPanel() { // Create buttons and add events calcButton = new JButton("Calculate"); calcButton.addActionListener(new CalcButtonListener()); clearButton = new JButton("Clear"); clearButton.addActionListener(new ClearButtonListener()); buttonPanel.add(calcButton); buttonPanel.add(clearButton); } @Override public void actionPerformed(ActionEvent e) { } private class CalcButtonListener implements ActionListener { public void actionPerformed(ActionEvent ae) { // Declare boolean variable boolean incorrect = true; // Set input variable to input text field text input = inputTF.getText(); ImageIcon newIcon; ImageIcon frowny = new ImageIcon(TrigCalcGUI.class.getResource("/Sad_Face.png")); Image gm = frowny.getImage(); Image newFrowny = gm.getScaledInstance(100, 100, java.awt.Image.SCALE_FAST); newIcon = new ImageIcon(newFrowny); // If boolean is true, throw exception if(incorrect) { try{Double.parseDouble(input); incorrect = false;} catch(NumberFormatException nfe) { String s = "Invalid Input " + "/n Input Must Be a Numerical value." + "/nPlease Press Ok and Try Again"; JOptionPane.showMessageDialog(null, s, "Invalid", JOptionPane.ERROR_MESSAGE, newIcon); inputTF.setText(""); inputTF.requestFocus(); } } // If boolean is not true, proceed with output if (incorrect != true) { /* Set each text field's output to the String double value * of inputTF */ sinTF.setText(input); cosTF.setText(input); tanTF.setText(input); cscTF.setText(input); secTF.setText(input); cotTF.setText(input); } } } /** * Private inner class that handles the event when * the user clicks the Exit button. */ private class ClearButtonListener implements ActionListener { public void actionPerformed(ActionEvent ae) { // Clear field sinTF.setText(""); cosTF.setText(""); tanTF.setText(""); cscTF.setText(""); secTF.setText(""); cotTF.setText(""); // Clear textfield and set cursor focus to field inputTF.setText(""); inputTF.requestFocus(); } } }

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  • Passing ActionListeners in Java, pack()

    - by Crystal
    Two questions. First question is I'm trying to create a simple form that when you press a button, it adds a Person object to the ArrayList. However, since I am not used to GUIs, I tried creating one and am first just trying to get the user input from the JTextField, create an ActionListener object of the appropriate type, so once that works, then I can pass in all the JTextField inputs to create my Person object. Unfortunately, I am not getting any data when I type in something to the firstName JTextField and was wondering if someone could look at my code below. import java.awt.*; import java.awt.event.*; import javax.swing.*; import java.util.List; import java.util.ArrayList; public class AddressBook { public static void main(String[] args) { EventQueue.invokeLater(new Runnable() { public void run() { AddressBookFrame frame = new AddressBookFrame(); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); JMenuBar menuBar = new JMenuBar(); frame.setJMenuBar(menuBar); JMenu fileMenu = new JMenu("File"); JMenuItem openItem = new JMenuItem("Open"); JMenuItem saveItem = new JMenuItem("Save"); JMenuItem saveAsItem = new JMenuItem("Save As"); JMenuItem printItem = new JMenuItem("Print"); JMenuItem exitItem = new JMenuItem("Exit"); fileMenu.add(openItem); fileMenu.add(saveItem); fileMenu.add(saveAsItem); fileMenu.add(printItem); fileMenu.add(exitItem); menuBar.add(fileMenu); JMenu editMenu = new JMenu("Edit"); JMenuItem newItem = new JMenuItem("New"); JMenuItem editItem = new JMenuItem("Edit"); JMenuItem deleteItem = new JMenuItem("Delete"); JMenuItem findItem = new JMenuItem("Find"); JMenuItem firstItem = new JMenuItem("First"); JMenuItem previousItem = new JMenuItem("Previous"); JMenuItem nextItem = new JMenuItem("Next"); JMenuItem lastItem = new JMenuItem("Last"); editMenu.add(newItem); editMenu.add(editItem); editMenu.add(deleteItem); editMenu.add(findItem); editMenu.add(firstItem); editMenu.add(previousItem); editMenu.add(nextItem); editMenu.add(lastItem); menuBar.add(editMenu); JMenu helpMenu = new JMenu("Help"); JMenuItem documentationItem = new JMenuItem("Documentation"); JMenuItem aboutItem = new JMenuItem("About"); helpMenu.add(documentationItem); helpMenu.add(aboutItem); menuBar.add(helpMenu); frame.setVisible(true); } }); } } class AddressBookFrame extends JFrame { public AddressBookFrame() { setLayout(new BorderLayout()); setTitle("Address Book"); setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT); AddressBookToolBar toolBar = new AddressBookToolBar(); add(toolBar, BorderLayout.NORTH); AddressBookStatusBar aStatusBar = new AddressBookStatusBar("5"); add(aStatusBar, BorderLayout.SOUTH); AddressBookForm form = new AddressBookForm(); add(form, BorderLayout.CENTER); } public static final int DEFAULT_WIDTH = 500; public static final int DEFAULT_HEIGHT = 500; } /* Create toolbar buttons and add buttons to toolbar */ class AddressBookToolBar extends JPanel { public AddressBookToolBar() { setLayout(new FlowLayout(FlowLayout.LEFT)); JToolBar bar = new JToolBar(); JButton newButton = new JButton("New"); JButton editButton = new JButton("Edit"); JButton deleteButton = new JButton("Delete"); JButton findButton = new JButton("Find"); JButton firstButton = new JButton("First"); JButton previousButton = new JButton("Previous"); JButton nextButton = new JButton("Next"); JButton lastButton = new JButton("Last"); bar.add(newButton); bar.add(editButton); bar.add(deleteButton); bar.add(findButton); bar.add(firstButton); bar.add(previousButton); bar.add(nextButton); bar.add(lastButton); add(bar); } } /* Creates the status bar string */ class AddressBookStatusBar extends JPanel { public AddressBookStatusBar(String statusBarString) { setLayout(new FlowLayout(FlowLayout.LEFT)); this.statusBarString = new JLabel("Total number of people: " + statusBarString); add(this.statusBarString); } private JLabel statusBarString; private int totalContacts; } class AddressBookForm extends JPanel { public AddressBookForm() { this.setLayout(new GridLayout(2, 1)); JPanel formPanel = new JPanel(); formPanel.setLayout(new GridLayout(4, 2)); JTextField firstName = new JTextField(20); JTextField lastName = new JTextField(20); JTextField telephone = new JTextField(20); JTextField email = new JTextField(20); JLabel firstNameLabel = new JLabel("First Name: ", JLabel.LEFT); formPanel.add(firstNameLabel); formPanel.add(firstName); JLabel lastNameLabel = new JLabel("Last Name: ", JLabel.LEFT); formPanel.add(lastNameLabel); formPanel.add(lastName); JLabel telephoneLabel = new JLabel("Telephone: ", JLabel.LEFT); formPanel.add(telephoneLabel); formPanel.add(telephone); JLabel emailLabel = new JLabel("Email: ", JLabel.LEFT); formPanel.add(emailLabel); formPanel.add(email); add(formPanel); JPanel buttonPanel = new JPanel(); JButton insertButton = new JButton("Insert"); JButton displayButton = new JButton("Display"); // create button actions AddressBookManager insertAction = new AddressBookManager(firstName.getText()); insertButton.addActionListener(insertAction); buttonPanel.add(insertButton); buttonPanel.add(displayButton); add(buttonPanel); } private List<Person> addressList = new ArrayList<Person>(); private class AddressBookManager implements ActionListener { public AddressBookManager(String text) { // addressList.add( setName(text); System.out.println("Test" + text); } public void actionPerformed(ActionEvent e) { System.out.println("Hello" + name); } public void setName(String name) { this.name = name; } private String name; } } Second question is, how do I make my form not take up the whole center space. I don't like the stretch look and was hoping the JTextFields could be just one line long, not a big box. Same thing with the buttons. Any thoughts? Thanks.

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