aermicioi.aedi.storage.locator

1 /**
2 
3 License:
4 	Boost Software License - Version 1.0 - August 17th, 2003
5 
6     Permission is hereby granted, free of charge, to any person or organization
7     obtaining a copy of the software and accompanying documentation covered by
8     this license (the "Software") to use, reproduce, display, distribute,
9     execute, and transmit the Software, and to prepare derivative works of the
10     Software, and to permit third-parties to whom the Software is furnished to
11     do so, all subject to the following:
12 
13     The copyright notices in the Software and this entire statement, including
14     the above license grant, this restriction and the following disclaimer,
15     must be included in all copies of the Software, in whole or in part, and
16     all derivative works of the Software, unless such copies or derivative
17     works are solely in the form of machine-executable object code generated by
18     a source language processor.
19 
20     THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
21     IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
22     FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
23     SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
24     FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
25     ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
26     DEALINGS IN THE SOFTWARE.
27 
28 Authors:
29 	Alexandru Ermicioi
30 **/
31 module aermicioi.aedi.storage.locator_aware;
32 
33 import aermicioi.aedi.storage.locator;
34 
35 /**
36 Interface for objects that are aware about an locator, and accept one of them.
37 **/
38 interface LocatorAware(Type = Object, KeyType = string) {
39 
40 	public {
41 
42 		/**
43 		Set a locator to object.
44 
45 		Params:
46 			locator = the locator that is set to oject.
47 
48 		Returns:
49 			LocatorAware.
50 		**/
51 		@property LocatorAware locator(Locator!(Type, KeyType) locator) @safe nothrow;
52 	}
53 }
54 
55 /**
56 Denotes a Locator that can delegate resource/object location to another Locator if it is available.
57 
58 Denotes a Locator that can delegate resource/object location to another Locator if it is available.
59 It is used to denote that a Locator when it doesn't contain the requested object will try to search it in another
60 Locator if it is available, and if it doesn't contain the resource it will throw NotFoundException.
61 
62 Note:
63 	A locator when delegates the task of resource location it should first check if locator in chain contains the
64 	object first, and fetch it afterwards. Such method is used to avoid an infinite loop when several DelegatingLocator are
65 	chained in a loop.
66 **/
67 alias DelegatingLocator = LocatorAware;
68 
69 /**
70 Mixin implementing LocatorAware interface for a component of type T.
71 **/
72 @safe mixin template LocatorAwareMixin(T : LocatorAware!(Z, X), Z, X) {
73     mixin LocatorAwareMixin!(Z, X);
74 }
75 
76 /**
77 ditto
78 **/
79 @safe mixin template LocatorAwareMixin(Type = Object, KeyType = string) {
80     import aermicioi.aedi.storage.locator;
81     private {
82         Locator!(Type, KeyType) locator_;
83     }
84 
85     @property {
86         /**
87         Set locator
88 
89         Params:
90             locator = the locator used somehow by locator aware component
91 
92         Returns:
93             typeof(this)
94         **/
95         typeof(this) locator(Locator!(Type, KeyType) locator) @safe nothrow
96         in (locator !is null, "A locator is expected not null.")
97         {
98             this.locator_ = locator;
99 
100             return this;
101         }
102 
103         /**
104         Get locator
105 
106         Returns:
107             Locator!(Type, KeyType)
108         **/
109         inout(Locator!(Type, KeyType)) locator() @safe nothrow inout
110         out(lc; lc !is null, "Cannot return a locator, when it wasn't set in first case.") {
111             return this.locator_;
112         }
113     }
114 }
115 
116 /**
117 Mixin implementing LocatorAware interface for a component of type T delegating to a decorated instance.
118 **/
119 @safe mixin template LocatorAwareDecoratorMixin(T : LocatorAware!(Z, X), Z, X) {
120     mixin LocatorAwareDecoratorMixin!(Z, X);
121 }
122 
123 @safe mixin template LocatorAwareDecoratorMixin(Type = Object, KeyType = string) {
124     import aermicioi.aedi.storage.locator;
125     @property {
126         /**
127         Set locator
128 
129         Params:
130             locator = the locator used somehow by locator aware component
131 
132         Returns:
133             typeof(this)
134         **/
135         typeof(this) locator(Locator!(Type, KeyType) locator) @safe
136         in (locator !is null, "A locator is expected not null.")
137         {
138             this.decorated.locator = locator;
139 
140             return this;
141         }
142 
143         /**
144         Get locator
145 
146         Returns:
147             Locator!(Type, KeyType)
148         **/
149         inout(Locator!(Type, KeyType)) locator() @safe inout
150         out(lc; lc !is null, "Cannot return a locator, when it wasn't set in first case.") {
151             return this.decorated.locator;
152         }
153     }
154 }