phonerecordstore.java

J2ME源代码

package util;

import java.util.Vector;

import javax.microedition.rms.RecordComparator;
import javax.microedition.rms.RecordEnumeration;
import javax.microedition.rms.RecordStore;
import javax.microedition.rms.RecordStoreException;

import model.PhoneItem;

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){}
		}
	}
	
	//增加纪录
	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;
	}
	
	//更新纪录
	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;
	}
	
	//删除一条纪录
	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();
		RecordEnumeration enum1=null;
		int ind=0;
		try{
			PhoneItem item=null;
			//enumerateRecords方法遍历所有元素
			enum1=phone.enumerateRecords(null, new InnerComparator(), false);
			 while(enum1.hasPreviousElement()){
	            	ind=enum1.previousRecordId();
	        	    item=new PhoneItem(ind,phone.getRecord(ind));
	            	items.addElement(item);
	            }
		}catch(Exception ex){ex.printStackTrace();}
        finally{
    		try{
    			enum1.destroy();
    		}catch(Exception e){}
    		
    		this.closePhone();//关闭RecordStore
	}
        //System.out.println("PhoneRecordStore++");
        return items;
	}
	//比较器
	private class InnerComparator implements RecordComparator{
		//对名字进行排序
		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;
		}
	}
	
        

}