1 /*
2  * Copyright (C) 2014 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 package com.android.camera.settings;
18 
19 import java.util.HashMap;
20 
21 /**
22  * A class for storing default values and possible values of
23  * SharedPreferences settings.  It is optional to store defaults
24  * and possible values for a setting.  If a default is not specified,
25  * the SettingsManager API chooses a default based on the type
26  * requested:
27  *
28  * <ul>getString: default is null</ul>
29  * <ul>getInteger: default is 0</ul>
30  * <ul>getBoolean: default is false</ul>
31  *
32  * If possible values aren't specified for a
33  * SharedPreferences key, then calling getIndexOfCurrentValue
34  * and setValueByIndex will throw an IllegalArgumentException.
35  */
36 class DefaultsStore {
37 
38     /**
39      * A class for storing a default value and set of possible
40      * values.  Since all settings values are saved as Strings in
41      * SharedPreferences, the default and possible values are
42      * Strings.  This simplifies default values management.
43      */
44     private static class Defaults {
45         private String mDefaultValue;
46         private String[] mPossibleValues;
47 
Defaults(String defaultValue, String[] possibleValues)48         public Defaults(String defaultValue, String[] possibleValues) {
49             mDefaultValue = defaultValue;
50             mPossibleValues = possibleValues;
51         }
52 
getDefaultValue()53         public String getDefaultValue() {
54             return mDefaultValue;
55         }
56 
getPossibleValues()57         public String[] getPossibleValues() {
58             return mPossibleValues;
59         }
60     }
61 
62     /** Map of Defaults for SharedPreferences keys. */
63     private static HashMap<String, Defaults> mDefaultsInternalStore =
64         new HashMap<String, Defaults>();
65 
66     /**
67      * Store a default value and a set of possible values
68      * for a SharedPreferences key.
69      */
storeDefaults(String key, String defaultValue, String[] possibleValues)70     public void storeDefaults(String key, String defaultValue, String[] possibleValues) {
71         Defaults defaults = new Defaults(defaultValue, possibleValues);
72         mDefaultsInternalStore.put(key, defaults);
73     }
74 
75     /**
76      * Get the default value for a SharedPreferences key,
77      * if one has been stored.
78      */
getDefaultValue(String key)79     public String getDefaultValue(String key) {
80         Defaults defaults = mDefaultsInternalStore.get(key);
81         if (defaults == null) {
82             return null;
83         }
84         return defaults.getDefaultValue();
85     }
86 
87     /**
88      * Get the set of possible values for a SharedPreferences key,
89      * if a set has been stored.
90      */
getPossibleValues(String key)91     public String[] getPossibleValues(String key) {
92         Defaults defaults = mDefaultsInternalStore.get(key);
93         if (defaults == null) {
94             return null;
95         }
96         return defaults.getPossibleValues();
97     }
98 }