| /* |
| * Copyright (C) 2017 The Android Open Source Project |
| * |
| * Licensed under the 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 android.support.v7.preference; |
| |
| import android.support.annotation.Nullable; |
| |
| import java.util.Set; |
| |
| /** |
| * A data store interface to be implemented and provided to the Preferences framework. This can be |
| * used to replace the default {@link android.content.SharedPreferences}, if needed. |
| * |
| * <p>In most cases you want to use {@link android.content.SharedPreferences} as it is automatically |
| * backed up and migrated to new devices. However, providing custom data store to preferences can be |
| * useful if your app stores its preferences in a local db, cloud or they are device specific like |
| * "Developer settings". It might be also useful when you want to use the preferences UI but |
| * the data are not supposed to be stored at all because they are valid per session only. |
| * |
| * <p>Once a put method is called it is full responsibility of the data store implementation to |
| * safely store the given values. Time expensive operations need to be done in the background to |
| * prevent from blocking the UI. You also need to have a plan on how to serialize the data in case |
| * the activity holding this object gets destroyed. |
| * |
| * <p>By default, all "put" methods throw {@link UnsupportedOperationException}. |
| * |
| * @see Preference#setPreferenceDataStore(PreferenceDataStore) |
| * @see PreferenceManager#setPreferenceDataStore(PreferenceDataStore) |
| */ |
| public abstract class PreferenceDataStore { |
| |
| /** |
| * Sets a {@link String} value to the data store. |
| * |
| * <p>Once the value is set the data store is responsible for holding it. |
| * |
| * @param key the name of the preference to modify |
| * @param value the new value for the preference |
| * @see #getString(String, String) |
| */ |
| public void putString(String key, @Nullable String value) { |
| throw new UnsupportedOperationException("Not implemented on this data store"); |
| } |
| |
| /** |
| * Sets a set of Strings to the data store. |
| * |
| * <p>Once the value is set the data store is responsible for holding it. |
| * |
| * @param key the name of the preference to modify |
| * @param values the set of new values for the preference |
| * @see #getStringSet(String, Set<String>) |
| */ |
| public void putStringSet(String key, @Nullable Set<String> values) { |
| throw new UnsupportedOperationException("Not implemented on this data store"); |
| } |
| |
| /** |
| * Sets an {@link Integer} value to the data store. |
| * |
| * <p>Once the value is set the data store is responsible for holding it. |
| * |
| * @param key the name of the preference to modify |
| * @param value the new value for the preference |
| * @see #getInt(String, int) |
| */ |
| public void putInt(String key, int value) { |
| throw new UnsupportedOperationException("Not implemented on this data store"); |
| } |
| |
| /** |
| * Sets a {@link Long} value to the data store. |
| * |
| * <p>Once the value is set the data store is responsible for holding it. |
| * |
| * @param key the name of the preference to modify |
| * @param value the new value for the preference |
| * @see #getLong(String, long) |
| */ |
| public void putLong(String key, long value) { |
| throw new UnsupportedOperationException("Not implemented on this data store"); |
| } |
| |
| /** |
| * Sets a {@link Float} value to the data store. |
| * |
| * <p>Once the value is set the data store is responsible for holding it. |
| * |
| * @param key the name of the preference to modify |
| * @param value the new value for the preference |
| * @see #getFloat(String, float) |
| */ |
| public void putFloat(String key, float value) { |
| throw new UnsupportedOperationException("Not implemented on this data store"); |
| } |
| |
| /** |
| * Sets a {@link Boolean} value to the data store. |
| * |
| * <p>Once the value is set the data store is responsible for holding it. |
| * |
| * @param key the name of the preference to modify |
| * @param value the new value for the preference |
| * @see #getBoolean(String, boolean) |
| */ |
| public void putBoolean(String key, boolean value) { |
| throw new UnsupportedOperationException("Not implemented on this data store"); |
| } |
| |
| /** |
| * Retrieves a {@link String} value from the data store. |
| * |
| * @param key the name of the preference to retrieve |
| * @param defValue value to return if this preference does not exist in the storage |
| * @return the value from the data store or the default return value |
| * @see #putString(String, String) |
| */ |
| @Nullable |
| public String getString(String key, @Nullable String defValue) { |
| return defValue; |
| } |
| |
| /** |
| * Retrieves a set of Strings from the data store. |
| * |
| * @param key the name of the preference to retrieve |
| * @param defValues values to return if this preference does not exist in the storage |
| * @return the values from the data store or the default return values |
| * @see #putStringSet(String, Set<String>) |
| */ |
| @Nullable |
| public Set<String> getStringSet(String key, @Nullable Set<String> defValues) { |
| return defValues; |
| } |
| |
| /** |
| * Retrieves an {@link Integer} value from the data store. |
| * |
| * @param key the name of the preference to retrieve |
| * @param defValue value to return if this preference does not exist in the storage |
| * @return the value from the data store or the default return value |
| * @see #putInt(String, int) |
| */ |
| public int getInt(String key, int defValue) { |
| return defValue; |
| } |
| |
| /** |
| * Retrieves a {@link Long} value from the data store. |
| * |
| * @param key the name of the preference to retrieve |
| * @param defValue value to return if this preference does not exist in the storage |
| * @return the value from the data store or the default return value |
| * @see #putLong(String, long) |
| */ |
| public long getLong(String key, long defValue) { |
| return defValue; |
| } |
| |
| /** |
| * Retrieves a {@link Float} value from the data store. |
| * |
| * @param key the name of the preference to retrieve |
| * @param defValue value to return if this preference does not exist in the storage |
| * @return the value from the data store or the default return value |
| * @see #putFloat(String, float) |
| */ |
| public float getFloat(String key, float defValue) { |
| return defValue; |
| } |
| |
| /** |
| * Retrieves a {@link Boolean} value from the data store. |
| * |
| * @param key the name of the preference to retrieve |
| * @param defValue value to return if this preference does not exist in the storage |
| * @return the value from the data store or the default return value |
| * @see #getBoolean(String, boolean) |
| */ |
| public boolean getBoolean(String key, boolean defValue) { |
| return defValue; |
| } |
| } |
| |