Help need for understanding program and error solution
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  1. #1
    Join Date
    Aug 2013
    Location
    Germany
    Posts
    1

    Post Help need for understanding program and error solution

    Hello,
    I am new in this forum. I have some problem to understand java programing assignment for my exam. Please can you help me what is the wrong in this program? I get confuse to understand this Java program.

    regards,
    Biswas


    import java.io.*;
    import java.util.ArrayList;
    import java.util.HashMap;
    import java.util.Collections;
    import java.util.Comparator;
    import java.util.Iterator;
    import java.util.List;
    import java.util.Map;

    /**
    * The following program should read an arbitrary number of files from a directory and store all their tokens in a member variable.
    * The program may contain some bugs interfering with the desired functionality.
    * Your tasks are:
    * 1. Understand the program and correct all errors that lead to erroneous behaviour. Comment your changes and shortly explain the reasons.
    * 2. The program also contains some questionable programming constructs (e.g. disregarding Java naming conventions, etc.).
    * Try to find as many as you can, and correct them. Comment your changes and shortly explain the reasons.
    * 3. Add the missing JavaDocs at a level of detail that you consider as appropriate.
    * 4. Write a <b>single</b> method that <b>returns</b> the number of items in tokenMap, the average length (as double value) of the elements in tokenMap after calling applyFilters(), and the number of tokens starting with "a" (case sensitive).
    * Output this information.
    *
    * @author zesch
    */
    public class ProgrammingSkillsTest {

    public final static String CHARSET = "ISO-8859-1";

    public File inputDir;

    public double nrofFiles;

    public int minimumCharacters;
    public int maximumCharacters;

    HashMap<String, Integer> tokenMap;

    public ProgrammingSkillsTest(File pInputDir, int pMinChars, int pMaxChars) {

    inputDir = pInputDir;
    minimumCharacters = pMinChars;
    maximumCharacters = pMaxChars;

    if ((pMinChars == 0) || (pMaxChars == 0)) {
    throw new RuntimeException("Configuration parameters have not been correctly initialized.");
    }
    }

    public void run() {
    readFiles();
    applyFilters();
    outputTokens();
    }

    private void readFiles() {

    File[] files = inputDir.listFiles();
    if (files == null) {
    System.err.println("Filelist is empty. Directory: " + inputDir.getAbsolutePath());
    System.exit(1);
    }

    for (int i = 0; i < files.length; i++) {
    File file = new File(files[i].getAbsoluteFile().toString());

    if (file.length() == 0) {
    System.out.println("Skipping emtpy file " + file.getAbsolutePath());
    continue;
    }

    System.out.println(file.getAbsolutePath());

    tokenMap = getFileTokens(file);
    }
    }

    private HashMap<String, Integer> getFileTokens(File infile) {

    HashMap<String, Integer> fileTokens = new HashMap<String, Integer>();

    BufferedReader in;
    String line;
    try {
    in = new BufferedReader(new InputStreamReader(new FileInputStream(infile), CHARSET));
    while ((line = in.readLine()) != null) {
    String lineParts[] = line.split(" ");
    for (String part : lineParts) {
    if (fileTokens.containsKey(part)) {
    fileTokens.put(part, fileTokens.get(part) + 1);
    }
    else {
    fileTokens.put(part, 1);
    }
    }
    }
    in.close();
    } catch (Exception e) {
    System.err.println(e);
    }

    return fileTokens;
    }

    private void applyFilters() {
    try {
    for (String token : tokenMap.keySet()) {
    if (token.length() < minimumCharacters || token.length() > maximumCharacters) {
    tokenMap.remove(token);
    }
    }
    }
    catch(Exception e) {}
    }

    private void outputTokens() {
    String output = "";
    for (String token : tokenMap.keySet()) {
    output += token + "\n";
    }
    System.out.println(output);
    }

    public static void main(String[] args) {
    if (args.length != 3) {
    System.err.println("Wrong number of parameters: java <application> <indir> <minChars> <maxChars>");
    System.exit(1);
    }

    File inputDir = new File(args[0]);
    int minChars = new Integer(args[1]);
    int maxChars = new Integer(args[2]);

    ProgrammingSkillsTest pst = new ProgrammingSkillsTest(inputDir, minChars, maxChars);
    pst.run();
    }
    }

  2. #2
    Join Date
    Jun 1999
    Location
    SW Missouri
    Posts
    3,447

    Re: Help need for understanding program and error solution

    what is the wrong in this program?
    Can you explain in more detail?
    Are there error messages? If so, copy the full text and paste it here.

    If the output is not what you want, copy the output and paste it here and also post what you want the output to look like.

    Also please edit your post and wrap the code in code tags:
    [code]
    >>>> your code here
    [/code]
    Norm

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