Preferences.java

/* Copyright (c) 2011, SaferMobile/MobileActive - https://safermobile.org */
/* See LICENSE for licensing information */
package org.safermobile.micro.utils;

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

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

public class Preferences {
	
	  private String mRecordStoreName;

	  private Hashtable mHashtable;

	  public Preferences(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, RecordStore.AUTHMODE_PRIVATE, 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, RecordStore.AUTHMODE_PRIVATE, 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();
	    }
	  }
	}