SharedPreferencesStore.java

/*
 * Copyright (c) 2015. Thomas Haertel
 *
 * Licensed under Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package com.thomashaertel.device.identification;

import android.content.Context;
import android.content.SharedPreferences;

import com.securepreferences.SecurePreferences;


public class SharedPreferencesStore implements KeyValueStore {

    private static final String DEFAULT_PREFERENCE_FILE = "app_prefs";

    private SharedPreferences mPreferences;

    public SharedPreferencesStore(Context ctx) {
        this(ctx, DEFAULT_PREFERENCE_FILE, false);
    }

    public SharedPreferencesStore(Context ctx, boolean secure) {
        this(ctx, DEFAULT_PREFERENCE_FILE, secure);
    }

    public SharedPreferencesStore(Context ctx, final String filename) {
        this(ctx, filename, false);
    }

    public SharedPreferencesStore(Context ctx, final String filename, boolean secure) {
        mPreferences = init(ctx, filename, secure);
    }

    private static SharedPreferences init(Context ctx, String filename, boolean secure) {
        SharedPreferences prefs = ctx.getSharedPreferences(filename, Context.MODE_PRIVATE);

        // if secure preferences should be used, wrap the shared preferences instance
        if (secure) {
            prefs = new SecurePreferences(ctx, prefs);
        }

        return prefs;
    }

    @Override
    public void clear() {
        mPreferences.edit().clear().apply();
    }

    @Override
    public boolean contains(String key) {
        return mPreferences.contains(key);
    }

    @Override
    public String get(String key) {
        return mPreferences.getString(key, null);
    }

    @Override
    public String put(String key, String value) {
        String old = mPreferences.getString(key, null);

        mPreferences.edit().putString(key, value).apply();

        return old;
    }

    @Override
    public boolean isEmpty() {
        return mPreferences.getAll().isEmpty();
    }

    @Override
    public String remove(String key) {
        String old = mPreferences.getString(key, null);

        mPreferences.edit().remove(key).apply();

        return old;
    }

    @Override
    public int size() {
        return mPreferences.getAll().size();
    }
}