FazBrowse GitHub Viewer
|
Trending
|
URL:
|
Home
Tools:
[Download Repo ZIP]
[View Raw Code]
[Original HTTPS Page]
tutorial/cdi-basic008.html at gh-pages · javaee/tutorial · GitHub
This repository was archived by the owner on Jan 28, 2019. It is now read-only.
javaee
tutorial
Repository navigation
Code
Issues
Pull requests
Actions
Security and quality
Insights
Expand file tree
Breadcrumbs
tutorial
/
cdi-basic008.html
Copy path
More file actions
More file actions
Latest commit
History
History
History
246 lines (232 loc) · 8.83 KB
Breadcrumbs
tutorial
/
cdi-basic008.html
Copy path
File metadata and controls
246 lines (232 loc) · 8.83 KB
Raw
Copy raw file
Download raw file
Open symbols panel
Edit and raw actions
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
<!DOCTYPE html
>
<
html
lang
="
en
"
>
<
head
>
<
meta
charset
="
utf-8
"
/>
<
title
>
Using Scopes
</
title
>
<
meta
name
="
viewport
"
content
="
width=device-width, initial-scale=1.0
"
>
<
link
href
="
css/style.css
"
rel
="
stylesheet
"
>
<
script
src
="
https://use.fontawesome.com/96c4d89611.js
"
>
</
script
>
</
head
>
<
body
>
<
table
id
="
doc-title
"
cellspacing
="
0
"
cellpadding
="
0
"
>
<
tr
>
<
td
align
="
left
"
valign
="
top
"
>
<
b
>
Java Platform, Enterprise Edition (Java EE) 8
</
b
>
<
br
/>
<
b
>
The Java EE Tutorial
</
b
>
<!-- <p class="beta">Beta Draft (Pre-General Availability)</p> -->
</
td
>
</
tr
>
</
table
>
<
hr
/>
<
table
width
="
90%
"
id
="
top-nav
"
cellspacing
="
0
"
cellpadding
="
0
"
>
<
colgroup
>
<
col
width
="
12%
"
/>
<
col
width
="
12%
"
/>
<
col
width
="
*
"
/>
</
colgroup
>
<
tr
>
<
td
align
="
left
"
>
<
a
href
="
cdi-basic007.html
"
>
<
span
class
="
vector-font
"
>
<
i
class
="
fa fa-arrow-circle-left
"
aria-hidden
="
true
"
>
</
i
>
</
span
>
<
span
style
="
position:relative;top:-2px;
"
>
Previous
</
span
>
</
a
>
</
td
>
<
td
align
="
left
"
>
<
a
href
="
cdi-basic009.html
"
>
<
span
class
="
vector-font
"
>
<
i
class
="
fa fa-arrow-circle-right vector-font
"
aria-hidden
="
true
"
>
</
i
>
</
span
>
<
span
style
="
position:relative;top:-2px;
"
>
Next
</
span
>
</
a
>
</
td
>
<
td
align
="
right
"
>
<
a
href
="
toc.html
"
>
<
span
class
="
vector-font
"
>
<
i
class
="
fa fa-list vector-font
"
aria-hidden
="
true
"
>
</
i
>
</
span
>
<
span
style
="
position:relative;top:-2px;
"
>
Contents
</
span
>
</
a
>
</
td
>
</
tr
>
</
table
>
<
div
id
="
preamble
"
>
<
div
class
="
sectionbody
"
>
<
div
class
="
paragraph
"
>
<
p
>
<
a
id
="
GJBBK
"
>
</
a
>
<
a
id
="
using-scopes
"
>
</
a
>
</
p
>
</
div
>
</
div
>
</
div
>
<
div
class
="
sect1
"
>
<
h2
id
="
_using_scopes
"
>
Using Scopes
</
h2
>
<
div
class
="
sectionbody
"
>
<
div
class
="
paragraph
"
>
<
p
>
For a web application to use a bean that injects another bean class, the
bean needs to be able to hold state over the duration of the user’s
interaction with the application. The way to define this state is to
give the bean a scope. You can give an object any of the scopes
described in
<
a
href
="
#GJDBG
"
>
Table 25-1
</
a
>
, depending on how you are using it.
</
p
>
</
div
>
<
div
class
="
paragraph
"
>
<
p
>
<
a
id
="
sthref126
"
>
</
a
>
<
a
id
="
GJDBG
"
>
</
a
>
</
p
>
</
div
>
<
div
class
="
paragraph
"
>
<
p
>
Table 25-1 Scopes
</
p
>
</
div
>
<
table
class
="
tableblock frame-all grid-all
"
style
="
width: 99%;
"
>
<
colgroup
>
<
col
style
="
width: 25%;
"
>
<
col
style
="
width: 25%;
"
>
<
col
style
="
width: 50%;
"
>
</
colgroup
>
<
tbody
>
<
tr
>
<
td
class
="
tableblock halign-left valign-top
"
>
<
p
class
="
tableblock
"
>
<
strong
>
Scope
</
strong
>
</
p
>
</
td
>
<
td
class
="
tableblock halign-left valign-top
"
>
<
p
class
="
tableblock
"
>
<
strong
>
Annotation
</
strong
>
</
p
>
</
td
>
<
td
class
="
tableblock halign-left valign-top
"
>
<
p
class
="
tableblock
"
>
<
strong
>
Duration
</
strong
>
</
p
>
</
td
>
</
tr
>
<
tr
>
<
td
class
="
tableblock halign-left valign-top
"
>
<
p
class
="
tableblock
"
>
Request
</
p
>
</
td
>
<
td
class
="
tableblock halign-left valign-top
"
>
<
p
class
="
tableblock
"
>
<
code
>
@RequestScoped
</
code
>
</
p
>
</
td
>
<
td
class
="
tableblock halign-left valign-top
"
>
<
p
class
="
tableblock
"
>
A user’s interaction with a web application
in a single HTTP request.
</
p
>
</
td
>
</
tr
>
<
tr
>
<
td
class
="
tableblock halign-left valign-top
"
>
<
p
class
="
tableblock
"
>
Session
</
p
>
</
td
>
<
td
class
="
tableblock halign-left valign-top
"
>
<
p
class
="
tableblock
"
>
<
code
>
@SessionScoped
</
code
>
</
p
>
</
td
>
<
td
class
="
tableblock halign-left valign-top
"
>
<
p
class
="
tableblock
"
>
A user’s interaction with a web application
across multiple HTTP requests.
</
p
>
</
td
>
</
tr
>
<
tr
>
<
td
class
="
tableblock halign-left valign-top
"
>
<
p
class
="
tableblock
"
>
Application
</
p
>
</
td
>
<
td
class
="
tableblock halign-left valign-top
"
>
<
p
class
="
tableblock
"
>
<
code
>
@ApplicationScoped
</
code
>
</
p
>
</
td
>
<
td
class
="
tableblock halign-left valign-top
"
>
<
p
class
="
tableblock
"
>
Shared state across all users'
interactions with a web application.
</
p
>
</
td
>
</
tr
>
<
tr
>
<
td
class
="
tableblock halign-left valign-top
"
>
<
p
class
="
tableblock
"
>
Dependent
</
p
>
</
td
>
<
td
class
="
tableblock halign-left valign-top
"
>
<
p
class
="
tableblock
"
>
<
code
>
@Dependent
</
code
>
</
p
>
</
td
>
<
td
class
="
tableblock halign-left valign-top
"
>
<
p
class
="
tableblock
"
>
The default scope if none is specified; it
means that an object exists to serve exactly one client (bean) and has
the same lifecycle as that client (bean).
</
p
>
</
td
>
</
tr
>
<
tr
>
<
td
class
="
tableblock halign-left valign-top
"
>
<
p
class
="
tableblock
"
>
Conversation
</
p
>
</
td
>
<
td
class
="
tableblock halign-left valign-top
"
>
<
p
class
="
tableblock
"
>
<
code
>
@ConversationScoped
</
code
>
</
p
>
</
td
>
<
td
class
="
tableblock halign-left valign-top
"
>
<
p
class
="
tableblock
"
>
A user’s interaction with a
servlet, including JavaServer Faces applications. The conversation scope
exists within developer-controlled boundaries that extend it across
multiple requests for long-running conversations. All long-running
conversations are scoped to a particular HTTP servlet session and may
not cross session boundaries.
</
p
>
</
td
>
</
tr
>
</
tbody
>
</
table
>
<
div
class
="
paragraph
"
>
<
p
>
The first three scopes are defined by both JSR 365 and the JavaServer
Faces specification. The last two are defined by JSR 365.
</
p
>
</
div
>
<
div
class
="
paragraph
"
>
<
p
>
All predefined scopes except
<
code
>
@Dependent
</
code
>
are contextual scopes. CDI
places beans of contextual scope in the context whose lifecycle is
defined by the Java EE specifications. For example, a session context
and its beans exist during the lifetime of an HTTP session. Injected
references to the beans are contextually aware. The references always
apply to the bean that is associated with the context for the thread
that is making the reference. The CDI container ensures that the objects
are created and injected at the correct time as determined by the scope
that is specified for these objects.
</
p
>
</
div
>
<
div
class
="
paragraph
"
>
<
p
>
You can also define and implement custom scopes, but that is an advanced
topic. Custom scopes are likely to be used by those who implement and
extend the CDI specification.
</
p
>
</
div
>
<
div
class
="
paragraph
"
>
<
p
>
A scope gives an object a well-defined lifecycle context. A scoped
object can be automatically created when it is needed and automatically
destroyed when the context in which it was created ends. Moreover, its
state is automatically shared by any clients that execute in the same
context.
</
p
>
</
div
>
<
div
class
="
paragraph
"
>
<
p
>
Java EE components, such as servlets and enterprise beans, and JavaBeans
components do not by definition have a well-defined scope. These
components are one of the following:
</
p
>
</
div
>
<
div
class
="
ulist
"
>
<
ul
>
<
li
>
<
p
>
Singletons, such as Enterprise JavaBeans singleton beans, whose state
is shared among all clients
</
p
>
</
li
>
<
li
>
<
p
>
Stateless objects, such as servlets and stateless session beans, which
do not contain client-visible state
</
p
>
</
li
>
<
li
>
<
p
>
Objects that must be explicitly created and destroyed by their client,
such as JavaBeans components and stateful session beans, whose state is
shared by explicit reference passing between clients
</
p
>
</
li
>
</
ul
>
</
div
>
<
div
class
="
paragraph
"
>
<
p
>
However, if you create a Java EE component that is a managed bean, then it
becomes a scoped object, which exists in a well-defined lifecycle
context.
</
p
>
</
div
>
<
div
class
="
paragraph
"
>
<
p
>
The web application for the
<
code
>
Printer
</
code
>
bean will use a simple request and
response mechanism, so the managed bean can be annotated as follows:
</
p
>
</
div
>
<
div
class
="
listingblock
"
>
<
div
class
="
content
"
>
<
pre
class
="
prettyprint highlight
"
>
<
code
class
="
language-oac_no_warn
"
data-lang
="
oac_no_warn
"
>
import javax.enterprise.context.RequestScoped;
import javax.inject.Inject;
@RequestScoped
public class Printer {
@Inject @Informal Greeting greeting;
...
}
</
code
>
</
pre
>
</
div
>
</
div
>
<
div
class
="
paragraph
"
>
<
p
>
Beans that use session, application, or conversation scope must be
serializable, but beans that use request scope do not have to be
serializable.
</
p
>
</
div
>
</
div
>
</
div
>
<
hr
/>
<
table
width
="
90%
"
id
="
bottom-nav
"
cellspacing
="
0
"
cellpadding
="
0
"
>
<
colgroup
>
<
col
width
="
12%
"
/>
<
col
width
="
12%
"
/>
<
col
width
="
*
"
/>
</
colgroup
>
<
tr
>
<
td
align
="
left
"
>
<
a
href
="
cdi-basic007.html
"
>
<
span
class
="
vector-font
"
>
<
i
class
="
fa fa-arrow-circle-left
"
aria-hidden
="
true
"
>
</
i
>
</
span
>
<
span
style
="
position:relative;top:-2px;
"
>
Previous
</
span
>
</
a
>
</
td
>
<
td
align
="
left
"
>
<
a
href
="
cdi-basic009.html
"
>
<
span
class
="
vector-font
"
>
<
i
class
="
fa fa-arrow-circle-right vector-font
"
aria-hidden
="
true
"
>
</
i
>
</
span
>
<
span
style
="
position:relative;top:-2px;
"
>
Next
</
span
>
</
a
>
</
td
>
<
td
align
="
right
"
>
<
a
href
="
toc.html
"
>
<
span
class
="
vector-font
"
>
<
i
class
="
fa fa-list vector-font
"
aria-hidden
="
true
"
>
</
i
>
</
span
>
<
span
style
="
position:relative;top:-2px;
"
>
Contents
</
span
>
</
a
>
</
td
>
</
tr
>
</
table
>
<
span
id
="
copyright
"
>
<
a
href
="
img/cpyr.adoc
"
>
<
img
src
="
img/oracle.gif
"
height
="
10px
"
alt
="
Oracle Logo
"
/>
<
span
>
Copyright © 2017, Oracle and/or its affiliates. All rights reserved.
</
span
>
</
a
>
</
span
>
<!--<p align="center" class="beta">Beta Draft (Pre-General Availability)</p> -->
</
body
>
</
html
>
Back
|
FazBrowse Home
|
New Git URL