Beispiel #1
0
  // call this method to write the description to the file
  // the file pointer must be already positioned
  // the description must have been set
  private void writeDescription() throws IOException {
    if (description.length() > DESCRIPTION_LENGTH)
      description = description.substring(0, DESCRIPTION_LENGTH);

    outStream.writeChars(description);
    for (int j = 0; j < (DESCRIPTION_LENGTH - description.length()); j++) outStream.writeChar(' ');
  }
Beispiel #2
0
 private void write(String partnum, String partdesc, int qty, int ucost) throws IOException {
   StringBuffer sb = new StringBuffer(partnum);
   if (sb.length() > PNUMLEN) sb.setLength(PNUMLEN);
   else if (sb.length() < PNUMLEN) {
     int len = PNUMLEN - sb.length();
     for (int i = 0; i < len; i++) sb.append(" ");
   }
   raf.writeChars(sb.toString());
   sb = new StringBuffer(partdesc);
   if (sb.length() > DESCLEN) sb.setLength(DESCLEN);
   else if (sb.length() < DESCLEN) {
     int len = DESCLEN - sb.length();
     for (int i = 0; i < len; i++) sb.append(" ");
   }
   raf.writeChars(sb.toString());
   raf.writeInt(qty);
   raf.writeInt(ucost);
 }
Beispiel #3
0
  // call this method to write the column names to the file
  // the file pointer must be already positioned
  private void writeColumnNames(ArrayList names) throws IOException {
    String column;
    for (int i = 0, numCols = names.size(); i < numCols; i++) {
      column = (String) names.get(i);
      if (column.length() > COLUMN_LENGTH) column = column.substring(0, COLUMN_LENGTH);

      outStream.writeChars(column);
      for (int j = 0; j < (COLUMN_LENGTH - column.length()); j++) outStream.writeChar(' ');
    }
  }
  // write a String to the file
  public boolean writeString(String str) {
    if (false == this.startedFlag) {
      System.err.println("TcpFileReadWriter: this object is closed already");
      return false;
    }

    try {
      raf.writeChars(str);
    } catch (Exception e) {
      e.printStackTrace();
      System.err.println("TCPFileReadWriter: writeString fail!!");
      return false;
    }

    return true;
  }
Beispiel #5
0
  public void writeOutput() throws IOException {
    //noinspection ResultOfMethodCallIgnored
    new File(path).mkdirs();

    RandomAccessFile randomAccessFile = null;
    try {
      randomAccessFile = new RandomAccessFile(path + "/" + getExportFileName(), "rw");
      randomAccessFile.setLength(0);
      randomAccessFile.writeChars(output);
    } finally {
      try {
        if (randomAccessFile != null) {
          randomAccessFile.close();
        }
      } catch (IOException e) {
        // do nothing
      }
    }
  }
Beispiel #6
0
  /** sample usage and testing */
  public static void main(String[] args) {
    Itemset is1 = new Itemset();
    is1.add(1);
    is1.add(2);
    Itemset is2 = new Itemset();
    is2.add(3);
    is2.add(2);
    Itemset is3 = new Itemset();
    is3.add(3);
    is3.add(1);
    Itemset is4 = new Itemset();
    is4.add(33);
    is4.add(3);

    ArrayList colNames = new ArrayList(3);
    colNames.add("cheese");
    colNames.add("pizza");
    colNames.add("beer");

    System.out.println("\n\nCreating invalid database:");
    try {
      RandomAccessFile invalid = new RandomAccessFile("invalid.db", "rw");
      invalid.writeChars(ID + " - a bogus file that looks like a valid one");
      invalid.close();
    } catch (Exception e) {
      System.out.println("Shouldn't have happened: " + e);
    }

    System.out.println("\n\nCreating corrupted database:");
    try {
      DBWriter corrupted = new DBWriter("corrupted.db");

      try {
        corrupted.addRow(is1);
      } catch (DBException e) {
        System.out.println(e);
      }

      corrupted.setDescription("a corrupted database");
      corrupted.setColumnNames(colNames);

      corrupted.addRow(is1);
      corrupted.setDescription("a corrupted database - 2");
      corrupted.setColumnNames(colNames);
      corrupted.addRow(is2);
      corrupted.setDescription("a corrupted database - 3");
      corrupted.addRow(is3);

      try {
        corrupted.addRow(is4);
      } catch (DBException e) {
        System.out.println(e);
      }

      corrupted.close();

      System.out.println("corrupting file");

      RandomAccessFile raf = new RandomAccessFile("corrupted.db", "rw");
      raf.seek(770);
      // replace the 2 in the second itemset with a 3
      raf.writeInt(3);
      raf.close();
    } catch (Exception e) {
      System.out.println("Shouldn't have happened: " + e);
    }

    System.out.println("\n\nCreating empty database:");
    try {
      DBWriter empty = new DBWriter("empty.db");

      empty.setDescription("an empty database");
      empty.setColumnNames(colNames);
      empty.close();
    } catch (Exception e) {
      System.out.println("Shouldn't have happened: " + e);
    }

    System.out.println("\n\nCreating correct database:");
    try {
      DBWriter correct = new DBWriter("correct.db");

      correct.setDescription("a correct database");
      correct.setColumnNames(colNames);

      correct.addRow(is1);
      correct.setDescription("a correct database - 2");
      correct.setColumnNames(colNames);
      correct.addRow(is2);
      correct.setDescription("a correct database - 3");
      correct.addRow(is3);

      correct.close();

      correct = new DBWriter("correct.db");

      correct.setColumnNames(colNames);

      correct.addRow(is1);
      correct.setDescription("a correct database - 4");
      correct.setColumnNames(colNames);
      correct.addRow(is2);
      correct.setDescription("a correct database - 5");
      correct.addRow(is3);

      correct.close();
    } catch (Exception e) {
      System.out.println("Shouldn't have happened: " + e);
    }

    System.out.println("\n\nOpening and closing DBWriter:");
    try {
      DBWriter bummer = new DBWriter("bummer.db");
      bummer.close();
    } catch (Exception e) {
      System.out.println("Shouldn't have happened: " + e);
    }
  }
Beispiel #7
0
  /**
   * Set the column names for the database.
   *
   * @param names the column names
   * @exception IOException from library call
   * @exception DBException size of <code>names</code> does not match number of columns
   */
  public void setColumnNames(ArrayList names) throws IOException, DBException {
    long namesSize = names.size();

    if (wroteColumnNames == false) {
      numColumns = namesSize;

      // ID
      outStream.writeChars(ID);

      // version number
      outStream.writeInt(1);
      outStream.writeInt(0);
      outStream.writeInt(0);

      headerSize =
          COLUMN_NAME_OFFSET
              + COLUMN_SIZE * numColumns
              + ID_SIZE
              + DESCRIPTION_SIZE
              + ID_SIZE
              + CRC_SIZE;
      outStream.writeLong(headerSize);

      // number of rows
      outStream.writeLong(0);

      // number of columns
      outStream.writeLong(numColumns);

      // columns
      writeColumnNames(names);

      // rest of the header
      outStream.writeChars(ID);

      // check if description has been set, otherwise fill in with blanks
      if (description != null) writeDescription();
      else {
        description = " ";
        writeDescription();
      }

      outStream.writeChars(ID);

      // CRC
      outStream.writeInt(0);

      wroteColumnNames = true;
    } else {
      if (namesSize != numColumns) throw new DBException("Cannot change the number of columns");
      else {
        if (needReposition == false) {
          lastPosition = outStream.getFilePointer();
          needReposition = true;
        }

        outStream.seek(COLUMN_NAME_OFFSET);

        writeColumnNames(names);
      }
    }
  }
 /* @see java.io.DataOutput.writeChars(String) */
 public void writeChars(String s) throws IOException {
   raf.writeChars(s);
 }