Sort Mixed Record DataType : RecordStore « J2ME « Java Tutorial






import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;

import javax.microedition.lcdui.Alert;
import javax.microedition.lcdui.AlertType;
import javax.microedition.lcdui.Command;
import javax.microedition.lcdui.CommandListener;
import javax.microedition.lcdui.Display;
import javax.microedition.lcdui.Displayable;
import javax.microedition.lcdui.Form;
import javax.microedition.midlet.MIDlet;
import javax.microedition.rms.RecordComparator;
import javax.microedition.rms.RecordEnumeration;
import javax.microedition.rms.RecordStore;

public class J2MESortMixedRecordDataTypeExample extends MIDlet implements CommandListener {
  private Display display;

  private Alert alert;

  private Form form = new Form("Mixed RecordEnumeration");

  private Command exit = new Command("Exit", Command.SCREEN, 1);

  private Command start = new Command("Start", Command.SCREEN, 1);

  private RecordStore recordstore = null;

  private RecordEnumeration recordEnumeration = null;

  private Comparator comparator = null;

  public J2MESortMixedRecordDataTypeExample() {
    display = Display.getDisplay(this);
    form.addCommand(exit);
    form.addCommand(start);
    form.setCommandListener(this);
  }

  public void startApp() {
    display.setCurrent(form);
  }

  public void pauseApp() {
  }

  public void destroyApp(boolean unconditional) {
  }

  public void commandAction(Command command, Displayable displayable) {
    if (command == exit) {
      destroyApp(true);
      notifyDestroyed();
    } else if (command == start) {
      try {
        recordstore = RecordStore.openRecordStore("myRecordStore", true);
        byte[] outputRecord;
        String outputString[] = { "Mary", "Bob", "Adam" };
        int outputInteger[] = { 15, 10, 5 };
        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
        DataOutputStream outputDataStream = new DataOutputStream(outputStream);
        for (int x = 0; x < 3; x++) {
          outputDataStream.writeUTF(outputString[x]);
          outputDataStream.writeInt(outputInteger[x]);
          outputDataStream.flush();
          outputRecord = outputStream.toByteArray();
          recordstore.addRecord(outputRecord, 0, outputRecord.length);
          outputStream.reset();
        }
        outputStream.close();
        outputDataStream.close();

        String[] inputString = new String[3];
        byte[] byteInputData = new byte[300];
        ByteArrayInputStream inputStream = new ByteArrayInputStream(byteInputData);
        DataInputStream inputDataStream = new DataInputStream(inputStream);
        StringBuffer buffer = new StringBuffer();
        comparator = new Comparator();
        recordEnumeration = recordstore.enumerateRecords(null, comparator, false);
        while (recordEnumeration.hasNextElement()) {
          recordstore.getRecord(recordEnumeration.nextRecordId(), byteInputData, 0);
          buffer.append(inputDataStream.readUTF());
          buffer.append(inputDataStream.readInt());
          buffer.append("\n");
          inputDataStream.reset();
        }
        alert = new Alert("Reading", buffer.toString(), null, AlertType.WARNING);
        alert.setTimeout(Alert.FOREVER);
        display.setCurrent(alert);
        inputDataStream.close();
        inputStream.close();
        recordstore.closeRecordStore();
        if (RecordStore.listRecordStores() != null) {
          RecordStore.deleteRecordStore("myRecordStore");
          comparator.compareClose();
          recordEnumeration.destroy();
        }
      } catch (Exception error) {
        alert = new Alert("Error Removing", error.toString(), null, AlertType.WARNING);
        alert.setTimeout(Alert.FOREVER);
        display.setCurrent(alert);
      }
    }
  }
}

class Comparator implements RecordComparator {
  private byte[] comparatorInputData = new byte[300];

  private ByteArrayInputStream comparatorInputStream = null;

  private DataInputStream comparatorInputDataType = null;

  public int compare(byte[] record1, byte[] record2) {
    int record1int, record2int;
    try {
      int maxlen = Math.max(record1.length, record2.length);
      if (maxlen > comparatorInputData.length) {
        comparatorInputData = new byte[maxlen];
      }
      comparatorInputStream = new ByteArrayInputStream(record1);
      comparatorInputDataType = new DataInputStream(comparatorInputStream);
      comparatorInputDataType.readUTF();
      record1int = comparatorInputDataType.readInt();
      comparatorInputStream = new ByteArrayInputStream(record2);
      comparatorInputDataType = new DataInputStream(comparatorInputStream);
      comparatorInputDataType.readUTF();
      record2int = comparatorInputDataType.readInt();
      if (record1int == record2int) {
        return RecordComparator.EQUIVALENT;
      } else if (record1int < record2int) {
        return RecordComparator.PRECEDES;
      } else {
        return RecordComparator.FOLLOWS;
      }
    } catch (Exception error) {
      return RecordComparator.EQUIVALENT;
    }
  }

  public void compareClose() {
    try {
      if (comparatorInputStream != null) {
        comparatorInputStream.close();
      }
      if (comparatorInputDataType != null) {
        comparatorInputDataType.close();
      }
    } catch (Exception error) {
    }
  }
}








31.47.RecordStore
31.47.1.Load yahoo stock quote
31.47.2.Add records to RecordStore
31.47.3.delete RecordStore
31.47.4.Filter FieldsFilter Fields
31.47.5.Get record from RecordStoreGet record from RecordStore
31.47.6.Save data to RecordStoreSave data to RecordStore
31.47.7.Record MonitorRecord Monitor
31.47.8.Retrieve AllRetrieve All
31.47.9.Sort FieldsSort Fields
31.47.10.Record Enumeration
31.47.11.RecordStore read and write
31.47.12.Read and write mixed data types with RecordStore
31.47.13.Mixed Record Enumeration
31.47.14.Sort records in RecordStore
31.47.15.Sort Mixed Record DataType
31.47.16.Search record in RecordStore
31.47.17.Search Mixed Record Data Type