thunderdb.java

来自「java的一个源代码」· Java 代码 · 共 80 行

package thunder.bolt;

import java.io.ByteArrayOutputStream;
import java.io.ByteArrayInputStream;
import java.io.DataOutputStream;
import java.io.DataInputStream;
import javax.microedition.rms.*;

public class thunderDB {
	private String thunderStr = "1";
	private int thunderNumeric = 0;
	private RecordStore rs = null;
	
	public thunderDB() {
		try {
			rs = RecordStore.openRecordStore("thunder",true);
		}catch(RecordStoreException rse) {}
		
		/*if(distillRecordStore() == null) 
		   addThunderRecord(this.thunderStr);
		else this.thunderStr = distillRecordStore();*/
	}
	
	private String distillRecordStore() {
		String thunderStrDistill = null;
		int i = 1;
		if(rs != null) {
			try {
				RecordEnumeration enum = rs.enumerateRecords(null,null,false);
				while((i < 2)&&(enum.hasNextElement())) {
					thunderStrDistill = new String(enum.nextRecord());
					this.thunderNumeric = enum.nextRecordId();
					i++;
				}
			}catch(Exception e) {}
		}
		return (String)(thunderStrDistill.trim());
	}
	
	private void addThunderRecord(String thunderStrNew) {
		ByteArrayOutputStream bos = new ByteArrayOutputStream();
		DataOutputStream dos = new DataOutputStream(bos);
		try {
			dos.writeUTF(thunderStrNew);
		}catch(Exception e) {}
		byte[] b = bos.toByteArray();
		try {
			rs.addRecord(b,0,b.length);
		}catch(RecordStoreException rse) {}
	}
	
	private void updateThunderRecord(String thunderStrNew) {
		ByteArrayOutputStream bos = new ByteArrayOutputStream();
		DataOutputStream dos = new DataOutputStream(bos);
		try {
			dos.writeUTF(thunderStrNew);
		}catch(Exception e) {}
		byte[] b = bos.toByteArray();
		try {
			rs.setRecord(1,b,0,b.length);
		}catch(RecordStoreException rse) {}
	}
	
	public String getRecordStoreData() {
		return distillRecordStore();
	}
	
	public boolean compareRecordStore(int pointNum) {
		boolean flag = false;
		int numPoint = 0;
		String str = "";//distillRecordStore();
		numPoint = (int)(Integer.parseInt(str));
		if(pointNum > numPoint) {
			updateThunderRecord(pointNum+"");
			str = distillRecordStore();
			flag = true;
		}
		return flag;
	}
}