1 | /* |
2 | Copyright (c) 2006 - 2008 Volker Krause <vkrause@kde.org> |
3 | |
4 | This library is free software; you can redistribute it and/or modify it |
5 | under the terms of the GNU Library General Public License as published by |
6 | the Free Software Foundation; either version 2 of the License, or (at your |
7 | option) any later version. |
8 | |
9 | This library is distributed in the hope that it will be useful, but WITHOUT |
10 | ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
11 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public |
12 | License for more details. |
13 | |
14 | You should have received a copy of the GNU Library General Public License |
15 | along with this library; see the file COPYING.LIB. If not, write to the |
16 | Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
17 | 02110-1301, USA. |
18 | */ |
19 | |
20 | #ifndef AKONADI_ATTRIBUTE_H |
21 | #define AKONADI_ATTRIBUTE_H |
22 | |
23 | #include "akonadi_export.h" |
24 | |
25 | #include <QtCore/QList> |
26 | |
27 | namespace Akonadi { |
28 | |
29 | /** |
30 | * @short Provides interface for custom attributes for Entity. |
31 | * |
32 | * This class is an interface for custom attributes, that can be stored |
33 | * in an entity. Attributes should be meta data, e.g. ACLs, quotas etc. |
34 | * that are not part of the entities' data itself. |
35 | * |
36 | * Note that attributes are per user, i.e. when an attribute is added to |
37 | * an entity, it only applies to the current user. |
38 | * |
39 | * To provide custom attributes, you have to subclass from this interface |
40 | * and reimplement the pure virtual methods. |
41 | * |
42 | * @code |
43 | * |
44 | * class SecrecyAttribute : public Akonadi::Attribute |
45 | * { |
46 | * public: |
47 | * enum Secrecy |
48 | * { |
49 | * Public, |
50 | * Private, |
51 | * Confidential |
52 | * }; |
53 | * |
54 | * SecrecyAttribute( Secrecy secrecy = Public ) |
55 | * : mSecrecy( secrecy ) |
56 | * { |
57 | * } |
58 | * |
59 | * void setSecrecy( Secrecy secrecy ) |
60 | * { |
61 | * mSecrecy = secrecy; |
62 | * } |
63 | * |
64 | * Secrecy secrecy() const |
65 | * { |
66 | * return mSecrecy; |
67 | * } |
68 | * |
69 | * virtual QByteArray type() const |
70 | * { |
71 | * return "secrecy"; |
72 | * } |
73 | * |
74 | * virtual Attribute* clone() const |
75 | * { |
76 | * return new SecrecyAttribute( mSecrecy ); |
77 | * } |
78 | * |
79 | * virtual QByteArray serialized() const |
80 | * { |
81 | * switch ( mSecrecy ) { |
82 | * case Public: return "public"; break; |
83 | * case Private: return "private"; break; |
84 | * case Confidential: return "confidential"; break; |
85 | * } |
86 | * } |
87 | * |
88 | * virtual void deserialize( const QByteArray &data ) |
89 | * { |
90 | * if ( data == "public" ) |
91 | * mSecrecy = Public; |
92 | * else if ( data == "private" ) |
93 | * mSecrecy = Private; |
94 | * else if ( data == "confidential" ) |
95 | * mSecrecy = Confidential; |
96 | * } |
97 | * } |
98 | * |
99 | * @endcode |
100 | * |
101 | * Additionally, you need to register your attribute with Akonadi::AttributeFactory |
102 | * for automatic deserialization during retrieving of collecitons or items: |
103 | * |
104 | * @code |
105 | * AttributeFactory::registerAttribute<SecrecyAttribute>(); |
106 | * @endcode |
107 | * |
108 | * Third party attributes need to be registered once by each application that uses |
109 | * them. So the above snippet needs to be in the resource that adds the attribute, |
110 | * and each application that uses the resource. This may be simplified in the future. |
111 | * |
112 | * The custom attributes can be used in the following way: |
113 | * |
114 | * @code |
115 | * |
116 | * Akonadi::Item item( "text/directory" ); |
117 | * SecrecyAttribute* attr = item.attribute<SecrecyAttribute>( Item::AddIfMissing ); |
118 | * attr->setSecrecy( SecrecyAttribute::Confidential ); |
119 | * |
120 | * @endcode |
121 | * |
122 | * and |
123 | * |
124 | * @code |
125 | * |
126 | * Akonadi::Item item = ... |
127 | * |
128 | * if ( item.hasAttribute<SecrecyAttribute>() ) { |
129 | * SecrecyAttribute *attr = item.attribute<SecrecyAttribute>(); |
130 | * |
131 | * SecrecyAttribute::Secrecy secrecy = attr->secrecy(); |
132 | * ... |
133 | * } |
134 | * @endcode |
135 | * |
136 | * @author Volker Krause <vkrause@kde.org> |
137 | */ |
138 | class AKONADI_EXPORT Attribute |
139 | { |
140 | public: |
141 | /** |
142 | * Describes a list of attributes. |
143 | */ |
144 | typedef QList<Attribute *> List; |
145 | |
146 | /** |
147 | * Returns the type of the attribute. |
148 | */ |
149 | virtual QByteArray type() const = 0; |
150 | |
151 | /** |
152 | * Destroys this attribute. |
153 | */ |
154 | virtual ~Attribute(); |
155 | |
156 | /** |
157 | * Creates a copy of this attribute. |
158 | */ |
159 | virtual Attribute *clone() const = 0; |
160 | |
161 | /** |
162 | * Returns a QByteArray representation of the attribute which will be |
163 | * storaged. This can be raw binary data, no encoding needs to be applied. |
164 | */ |
165 | virtual QByteArray serialized() const = 0; |
166 | |
167 | /** |
168 | * Sets the data of this attribute, using the same encoding |
169 | * as returned by toByteArray(). |
170 | * |
171 | * @param data The encoded attribute data. |
172 | */ |
173 | virtual void deserialize(const QByteArray &data) = 0; |
174 | }; |
175 | |
176 | } |
177 | |
178 | #endif |
179 | |