phonerecordstore.java

手机电话本 初学者

/*
 * Created on 2005-2-3
 *
 * TODO To change the template for this generated file go to
 * Window - Preferences - Java - Code Style - Code Templates
 */
package net.garrey.util;
import javax.microedition.rms.RecordComparator;
import javax.microedition.rms.RecordStore;
import javax.microedition.rms.RecordEnumeration;
import javax.microedition.rms.RecordStoreException;
import net.garrey.model.PhoneItem;
import java.util.Vector;
/**
 * @author Administrator
 *
 * TODO To change the template for this generated type comment go to
 * Window - Preferences - Java - Code Style - Code Templates
 */
public class PhoneRecordStore {
	private static final String RECORDSTORE_NAME="PHONE_DB";
	private static RecordStore phone;
	private  UIController controller;
		
	public PhoneRecordStore(UIController control){
		controller=control;
	}
	//打开RecordStore，没有则创建
    public void openPhone() {
        try {
            phone = RecordStore.openRecordStore(RECORDSTORE_NAME, true);
        }catch (RecordStoreException ex) {            
            phone=null;
        }
    }
    //关闭RecordStore
    public void closePhone() {
        if (phone!= null) {
            try {
                phone.closeRecordStore();
                phone=null;
            } catch (RecordStoreException ex) {}
        }
    }
    //增加记录
    public int addPhone(PhoneItem item) {
                   
                try {
                    this.openPhone();
                    byte[] data=item.getBytes();
                    int id=phone.getNextRecordID();
                	int rec =phone.addRecord(data,0,data.length);
                	this.closePhone();
                	return id;
                } catch (RecordStoreException ex) { }
        
        return -1;
    }
    //更新记录
    public void updatePhone(PhoneItem item){

            try {
                this.openPhone();       
                byte[] data=item.getBytes();
            	phone.setRecord(item.getId(),data,0,data.length);
            	this.closePhone();
            } catch (RecordStoreException ex) { }
    }
    //访问一条记录
    public PhoneItem getPhone(int id){
        PhoneItem item=null;

            try {
                this.openPhone();
            	new PhoneItem(id,phone.getRecord(id));
            	this.closePhone();
            } catch (RecordStoreException ex) { }

         return item;
    }
    //删除一条记录
    public void deletePhone(int id){
            try {
                this.openPhone();
            	phone.deleteRecord(id);
            	this.closePhone();
            } catch (RecordStoreException ex) {}
    }
    //访问所有记录
    public Vector getPhones(){
        Vector items=new Vector(10,3);
        this.openPhone();//打开RecordStore
        RecordEnumeration enum=null;
        int ind=0;
        try{
            PhoneItem item=null;
        	enum=phone.enumerateRecords(null,new InnerComparator(),false);
            
            while(enum.hasPreviousElement()){
            	ind=enum.previousRecordId();
        	    item=new PhoneItem(ind,phone.getRecord(ind));
            	items.addElement(item);
            }
            
        }catch(Exception ex){ex.printStackTrace();}
        finally{
        		try{
        			enum.destroy();
        		}catch(Exception e){}
        		
        		this.closePhone();//关闭RecordStore
        }//end finally
    
        return items;
    }
    //一个简单的比较器
    private class InnerComparator implements RecordComparator{
        public int compare(byte[] rec1, byte[] rec2){
            if(rec1.length>rec2.length)
                return FOLLOWS;
            else if(rec1.length<rec2.length)
                return PRECEDES;
            else 
                return EQUIVALENT;
        }

    }
}