File read and write : Input Output Stream « File Input Output « Java





File read and write

File read and write
/*
Software Architecture Design Patterns in Java
by Partha Kuchana 

Auerbach Publications

*/


import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Vector;

public class FileUtil {

  DataOutputStream dos;

  /*
   * Utility method to write a given text to a file
   */
  public boolean writeToFile(String fileName, String dataLine,
      boolean isAppendMode, boolean isNewLine) {
    if (isNewLine) {
      dataLine = "\n" + dataLine;
    }

    try {
      File outFile = new File(fileName);
      if (isAppendMode) {
        dos = new DataOutputStream(new FileOutputStream(fileName, true));
      } else {
        dos = new DataOutputStream(new FileOutputStream(outFile));
      }

      dos.writeBytes(dataLine);
      dos.close();
    } catch (FileNotFoundException ex) {
      return (false);
    } catch (IOException ex) {
      return (false);
    }
    return (true);

  }

  /*
   * Reads data from a given file
   */
  public String readFromFile(String fileName) {
    String DataLine = "";
    try {
      File inFile = new File(fileName);
      BufferedReader br = new BufferedReader(new InputStreamReader(
          new FileInputStream(inFile)));

      DataLine = br.readLine();
      br.close();
    } catch (FileNotFoundException ex) {
      return (null);
    } catch (IOException ex) {
      return (null);
    }
    return (DataLine);

  }

  public boolean isFileExists(String fileName) {
    File file = new File(fileName);
    return file.exists();
  }

  public boolean deleteFile(String fileName) {
    File file = new File(fileName);
    return file.delete();
  }

  /*
   * Reads data from a given file into a Vector
   */

  public Vector fileToVector(String fileName) {
    Vector v = new Vector();
    String inputLine;
    try {
      File inFile = new File(fileName);
      BufferedReader br = new BufferedReader(new InputStreamReader(
          new FileInputStream(inFile)));

      while ((inputLine = br.readLine()) != null) {
        v.addElement(inputLine.trim());
      }
      br.close();
    } // Try
    catch (FileNotFoundException ex) {
      //
    } catch (IOException ex) {
      //
    }
    return (v);
  }

  /*
   * Writes data from an input vector to a given file
   */

  public void vectorToFile(Vector v, String fileName) {
    for (int i = 0; i < v.size(); i++) {
      writeToFile(fileName, (String) v.elementAt(i), true, true);
    }
  }

  /*
   * Copies unique rows from a source file to a destination file
   */

  public void copyUniqueElements(String sourceFile, String resultFile) {
    Vector v = fileToVector(sourceFile);
    v = MiscUtil.removeDuplicates(v);
    vectorToFile(v, resultFile);
  }

} // end FileUtil

class MiscUtil {

  public static boolean hasDuplicates(Vector v) {
    int i = 0;
    int j = 0;
    boolean duplicates = false;

    for (i = 0; i < v.size() - 1; i++) {
      for (j = (i + 1); j < v.size(); j++) {
        if (v.elementAt(i).toString().equalsIgnoreCase(
            v.elementAt(j).toString())) {
          duplicates = true;
        }

      }

    }

    return duplicates;
  }

  public static Vector removeDuplicates(Vector s) {
    int i = 0;
    int j = 0;
    boolean duplicates = false;

    Vector v = new Vector();

    for (i = 0; i < s.size(); i++) {
      duplicates = false;
      for (j = (i + 1); j < s.size(); j++) {
        if (s.elementAt(i).toString().equalsIgnoreCase(
            s.elementAt(j).toString())) {
          duplicates = true;
        }

      }
      if (duplicates == false) {
        v.addElement(s.elementAt(i).toString().trim());
      }

    }

    return v;
  }

  public static Vector removeDuplicateDomains(Vector s) {
    int i = 0;
    int j = 0;
    boolean duplicates = false;
    String str1 = "";
    String str2 = "";

    Vector v = new Vector();

    for (i = 0; i < s.size(); i++) {
      duplicates = false;
      for (j = (i + 1); j < s.size(); j++) {
        str1 = "";
        str2 = "";
        str1 = s.elementAt(i).toString().trim();
        str2 = s.elementAt(j).toString().trim();
        if (str1.indexOf('@') > -1) {
          str1 = str1.substring(str1.indexOf('@'));
        }
        if (str2.indexOf('@') > -1) {
          str2 = str2.substring(str2.indexOf('@'));
        }

        if (str1.equalsIgnoreCase(str2)) {
          duplicates = true;
        }

      }
      if (duplicates == false) {
        v.addElement(s.elementAt(i).toString().trim());
      }

    }

    return v;
  }

  public static boolean areVectorsEqual(Vector a, Vector b) {
    if (a.size() != b.size()) {
      return false;
    }

    int i = 0;
    int vectorSize = a.size();
    boolean identical = true;

    for (i = 0; i < vectorSize; i++) {
      if (!(a.elementAt(i).toString().equalsIgnoreCase(b.elementAt(i)
          .toString()))) {
        identical = false;
      }
    }

    return identical;
  }

  public static Vector removeDuplicates(Vector a, Vector b) {

    int i = 0;
    int j = 0;
    boolean present = true;
    Vector v = new Vector();

    for (i = 0; i < a.size(); i++) {
      present = false;
      for (j = 0; j < b.size(); j++) {
        if (a.elementAt(i).toString().equalsIgnoreCase(
            b.elementAt(j).toString())) {
          present = true;
        }
      }
      if (!(present)) {
        v.addElement(a.elementAt(i));
      }
    }

    return v;
  }

}// end of class



           
       










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