apppreferences.java

一个基于J2ME技术的程序,使你可以远程控制装有服务端的PC.

/*
 * JRemCntl - Copyright (C) 2007 Filippo Di Vattimo <[e-mail]>
 * See COPYING
 */

package fildiv.jremcntl.client.core;

import java.util.Enumeration;
import java.util.Hashtable;

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

class AppPreferences {
	private String mRecordStoreName;

	private Hashtable mHashtable;

	public AppPreferences(String recordStoreName) throws RecordStoreException {
		mRecordStoreName = recordStoreName;
		mHashtable = new Hashtable();
		load();
	}

	public String get(String key) {
		return (String) mHashtable.get(key);
	}

	public void put(String key, String value) {
		if (value == null)
			value = "";
		mHashtable.put(key, value);
	}

	private void load() throws RecordStoreException {
		RecordStore rs = null;
		RecordEnumeration re = null;

		try {
			rs = RecordStore.openRecordStore(mRecordStoreName, true);
			re = rs.enumerateRecords(null, null, false);
			while (re.hasNextElement()) {
				byte[] raw = re.nextRecord();
				String pref = new String(raw);
				// Parse out the name.
				int index = pref.indexOf('|');
				String name = pref.substring(0, index);
				String value = pref.substring(index + 1);
				put(name, value);
			}
		} finally {
			if (re != null)
				re.destroy();
			if (rs != null)
				rs.closeRecordStore();
		}
	}

	public void save() throws RecordStoreException {
		RecordStore rs = null;
		RecordEnumeration re = null;
		try {
			rs = RecordStore.openRecordStore(mRecordStoreName, true);
			re = rs.enumerateRecords(null, null, false);

			// First remove all records, a little clumsy.
			while (re.hasNextElement()) {
				int id = re.nextRecordId();
				rs.deleteRecord(id);
			}

			// Now save the preferences records.
			Enumeration keys = mHashtable.keys();
			while (keys.hasMoreElements()) {
				String key = (String) keys.nextElement();
				String value = get(key);
				String pref = key + "|" + value;
				byte[] raw = pref.getBytes();
				rs.addRecord(raw, 0, raw.length);
			}
		} finally {
			if (re != null)
				re.destroy();
			if (rs != null)
				rs.closeRecordStore();
		}
	}
}