/*
* Copyright 2013 serso aka se.solovyev
*
* 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.
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
* Contact details
*
* Email: se.solovyev@gmail.com
* Site: http://se.solovyev.org
*/
package org.solovyev.android.prefs;
import android.content.SharedPreferences;
import javax.annotation.Nonnull;
import javax.annotation.Nullable;
/**
* Class for working with android preferences: can save and load preferences, convert them to custom java objects
* and use default value;
*
* @param <T> type of java object preference
*/
public interface Preference<T> {
/**
* Method returns key of preference used in android: the key with which current preference is saved in persistence
*
* @return android preference key
*/
@Nonnull
String getKey();
/**
* @return default preference value, may be null
*/
T getDefaultValue();
/**
* NOTE: this method can throw runtime exceptions if errors occurred while extracting preferences values
*
* @param preferences application preferences
* @return value from preference, default value if no value in preference was found
*/
T getPreference(@Nonnull SharedPreferences preferences);
/**
* NOTE: this method SHOULD not throw any runtime exceptions BUT return default value if any error occurred
*
* @param preferences application preferences
* @return value from preference, default value if no value in preference was found or error occurred
*/
T getPreferenceNoError(@Nonnull SharedPreferences preferences);
/**
* Method puts (saves) preference represented by <code>value</code> in <code>preferences</code> container
* @param editor preferences container
* @param value value to be saved
*/
void putPreference(@Nonnull SharedPreferences.Editor editor, @Nullable T value);
void putPreference(@Nonnull SharedPreferences preferences, @Nullable T value);
/**
* Method saves default value in <code>preferences</code> container.
* Should behave exactly as <code>p.putPreference(preferences, p.getDefaultValue())</code>
*
* @param editor preferences editor
*/
void putDefault(@Nonnull SharedPreferences.Editor editor);
void putDefault(@Nonnull SharedPreferences preferences);
/**
* @param preferences preferences container
* @return true if any value is saved in preferences container, false - otherwise
*/
boolean isSet(@Nonnull SharedPreferences preferences);
/**
* Method applies default value to preference only if explicit value is not set
*
*
* @param preferences preferences
* @param editor preferences editor
* @return true if default values have been applied, false otherwise
*/
boolean tryPutDefault(@Nonnull SharedPreferences preferences, @Nonnull SharedPreferences.Editor editor);
boolean tryPutDefault(@Nonnull SharedPreferences preferences);
/**
* @param key preference key
* @return true if current preferences has the same key
*/
boolean isSameKey(@Nonnull String key);
}