record.java

支持蓝牙的手机游戏 支持蓝牙的手机游戏的分析与实现

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package org.challenge.chengshi.record;

import java.util.Enumeration;
import java.util.Hashtable;
import javax.microedition.rms.RecordComparator;
import javax.microedition.rms.RecordEnumeration;
import javax.microedition.rms.RecordStore;
import javax.microedition.rms.RecordStoreException;
import javax.microedition.rms.RecordStoreNotOpenException;

/**
 *
 * @author challenge
 */
public class Record {
    RecordStore dataBase;
    private static final int MAXLENGTH=5;
    String fileName="org.challenge.chengshi.record";
    
    public Record(){
        try {
            this.dataBase = RecordStore.openRecordStore(fileName, true);
        } catch (RecordStoreException ex) {
            ex.printStackTrace();
        }
    }
    
    public void save(int step){
        try {
            RecordEnumeration re=this.getRecord();
            int last;
            if(re!=null&&re.numRecords()>=MAXLENGTH){
                last=re.previousRecordId();
                if(step<Integer.parseInt(new String(this.dataBase.getRecord(last)))){
                    this.dataBase.deleteRecord(last);
                }else{
                    return;
                }
            }
            byte[] array = (step + "").getBytes();
            this.dataBase.addRecord(array, 0, array.length);
        } catch (RecordStoreNotOpenException ex) {
            ex.printStackTrace();
        } catch (RecordStoreException ex) {
            ex.printStackTrace();
        }
    }
    
    private class SearchComparator implements RecordComparator{

        public int compare(byte[] data1, byte[] data2) {
            int step1=Integer.parseInt(new String(data1));
            int step2=Integer.parseInt(new String(data2));
            if(step1<step2){
                return RecordComparator.PRECEDES;
            }else if(step1>step2){
                return RecordComparator.FOLLOWS;
            }else{
                return RecordComparator.EQUIVALENT;
            }
        }
        
    }
    
    public RecordEnumeration getRecord(){
        try {
            this.dataBase.addRecord((12+"").getBytes(), 0, (12+"").length());
            this.dataBase.addRecord((10+"").getBytes(), 0, (10+"").length());
            this.dataBase.addRecord((14+"").getBytes(), 0, (14+"").length());
            RecordEnumeration re = this.dataBase.enumerateRecords(null, new SearchComparator(), false);
            return re;
        } catch (Exception ex) {
            ex.printStackTrace();
        }
        return null;
    }

}