listfilter_midlet.java

《J2ME无线移动游戏开发》一书的配套光盘

package ch12;

import javax.microedition.midlet.*;
import javax.microedition.rms.*;

public class ListFilter_MIDlet
    extends MIDlet
    implements RecordFilter {

  private RecordStore rs = null;
  private RecordEnumeration re = null;
  public ListFilter_MIDlet() {
    try {
      rs.deleteRecordStore("test");
      rs = RecordStore.openRecordStore("test", true);
      byte[] data = new byte[3];
      data[0] = 1;
      data[1] = 2;
      data[2] = 3;
      rs.addRecord(data, 0, data.length);
      data[0] = 4;
      data[1] = 5;
      data[2] = 6;
      rs.addRecord(data, 0, data.length);
      data[0] = 1;
      data[1] = 3;
      data[2] = 2;
      rs.addRecord(data, 0, data.length);
      data[0] = 6;
      data[1] = 5;
      data[2] = 6;
      rs.addRecord(data, 0, data.length);

      re = rs.enumerateRecords(this, null, false);
      System.out.println("记录集中共有：" + rs.getNumRecords() + "条记录");
      System.out.println("枚举集中共有：" + re.numRecords() + "条记录");
      System.out.println("记录数据首字节为1的记录如下：");
      while (re.hasNextElement()) {
        try {
          int j = re.nextRecordId();
          data = rs.getRecord(j);
          String s = "";
          for (int i = 0; i < data.length; i++) {
            s = s + data[i];
          }
          System.out.println("记录ID号为" + j + "的记录:" + s);
        }
        catch (Exception e) {
          System.out.println(e.getMessage());
        }
      }
    }
    catch (RecordStoreNotOpenException rsnoe) {
      System.out.println(rsnoe.getMessage());
    }
    catch (InvalidRecordIDException iride) {
      System.out.println(iride.getMessage());
    }
    catch (RecordStoreException rse) {
      System.out.println(rse.getMessage());
    }

  }

  public boolean matches(byte[] candidate) {
    if (candidate[0] == 1) {
      return true;
    }
    else {
      return false;
    }
  }

  public void startApp() {

  }

  public void pauseApp() {
  }

  public void destroyApp(boolean unconditional) {
    try {
      if (rs != null) {
        rs.closeRecordStore();
      }
    }
    catch (RecordStoreException rse) {
      System.out.println(rse.getMessage());
    }
  }
}