com.halseyburgund.rwframework.util.RWSharedPrefsHelper.java Source code

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Here is the source code for com.halseyburgund.rwframework.util.RWSharedPrefsHelper.java

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/*
ROUNDWARE
   a participatory, location-aware media platform
   Android client library
  Copyright (C) 2008-2012 Halsey Solutions, LLC
   with contributions by Rob Knapen (shuffledbits.com) and Dan Latham
   http://roundware.org | contact@roundware.org
    
   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.
    
This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.
    
You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/
package com.halseyburgund.rwframework.util;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import com.halseyburgund.rwframework.core.RWConfiguration;

import android.content.Context;
import android.content.SharedPreferences;
import android.util.Log;

/**
 * Helper methods for saving and loading JSON data in Shared Preferences. It
 * can be used to create a cache of data retrieved from the server for use in
 * an off-line state.
 * 
 * @author Rob Knapen
 */
public class RWSharedPrefsHelper {

    // debugging
    private final static String TAG = "RWSharedPrefsHelper";

    // prefix used in keys in the shared preferences
    private static final String PREFIX = "json_";

    /**
     * Parses the specified JSON data into a JSON Object and stores its
     * string representation into the shared preferences with the specified
     * name.
     *  
     * @param context to be used to access shared preferences
     * @param preferencesName of shared preferences to be used
     * @param key for storing the data
     * @param jsonData to be stored
     */
    public static void saveJSONObject(Context context, String preferencesName, String key, String jsonData) {
        try {
            JSONObject object = new JSONObject(jsonData);
            SharedPreferences settings = context.getSharedPreferences(preferencesName, Context.MODE_PRIVATE);
            SharedPreferences.Editor editor = settings.edit();
            editor.putString(RWSharedPrefsHelper.PREFIX + key, object.toString());
            editor.commit();
        } catch (JSONException e) {
            Log.e(TAG, RWConfiguration.JSON_SYNTAX_ERROR_MESSAGE, e);
        }
    }

    /**
     * Parses the specified JSON data into a JSON Array and stores its
     * string representation into the shared preferences with the specified
     * name.
     *  
     * @param context to be used to access shared preferences
     * @param preferencesName of shared preferences to be used
     * @param key for storing the data
     * @param jsonData to be stored
     */
    public static void saveJSONArray(Context context, String preferencesName, String key, String jsonData) {
        try {
            JSONArray array = new JSONArray(jsonData);
            SharedPreferences settings = context.getSharedPreferences(preferencesName, Context.MODE_PRIVATE);
            SharedPreferences.Editor editor = settings.edit();
            editor.putString(RWSharedPrefsHelper.PREFIX + key, array.toString());
            editor.commit();
        } catch (JSONException e) {
            Log.e(TAG, RWConfiguration.JSON_SYNTAX_ERROR_MESSAGE, e);
        }
    }

    /**
     * Retrieves the data for the specified key from the shared preferences
     * and tries to create a JSON Object from it, which string representation
     * will be returned
     * 
     * @param context to be used to access shared preferences
     * @param preferencesName of shared preferences to be used
     * @param key for retrieving the data
     * @return string representation of the JSON object data retrieved
     */
    public static String loadJSONObject(Context context, String preferencesName, String key) {
        try {
            SharedPreferences settings = context.getSharedPreferences(preferencesName, Context.MODE_PRIVATE);
            JSONObject object = new JSONObject(settings.getString(RWSharedPrefsHelper.PREFIX + key, "{}"));
            return object.toString();
        } catch (JSONException e) {
            Log.e(TAG, RWConfiguration.JSON_SYNTAX_ERROR_MESSAGE, e);
            return null;
        }
    }

    /**
     * Retrieves the data for the specified key from the shared preferences
     * and tries to create a JSON Array from it, which string representation
     * will be returned
     * 
     * @param context to be used to access shared preferences
     * @param preferencesName of shared preferences to be used
     * @param key for retrieving the data
     * @return string representation of the JSON array data retrieved
     */
    public static String loadJSONArray(Context context, String preferencesName, String key) {
        try {
            SharedPreferences settings = context.getSharedPreferences(preferencesName, Context.MODE_PRIVATE);
            JSONArray array = new JSONArray(settings.getString(RWSharedPrefsHelper.PREFIX + key, "[]"));
            return array.toString();
        } catch (JSONException e) {
            Log.e(TAG, RWConfiguration.JSON_SYNTAX_ERROR_MESSAGE, e);
            return null;
        }
    }

    /**
     * Removes the data with the specified key from the indicated shared
     * preferences.
     * 
     * @param context to be used to access shared preferences
     * @param preferencesName of shared preferences to be used
     * @param key for data to be deleted
     */
    public static void remove(Context context, String preferencesName, String key) {
        SharedPreferences settings = context.getSharedPreferences(preferencesName, Context.MODE_PRIVATE);
        if (settings.contains(RWSharedPrefsHelper.PREFIX + key)) {
            SharedPreferences.Editor editor = settings.edit();
            editor.remove(RWSharedPrefsHelper.PREFIX + key);
            editor.commit();
        }
    }

}