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new 9c62c1335 Cleans up content
9c62c1335 is described below
commit 9c62c1335b7a22c9088139b67858dd0091ded8d5
Author: Lukasz Lenart <[email protected]>
AuthorDate: Thu Oct 13 14:48:07 2022 +0200
Cleans up content
---
.../execute-and-wait-interceptor.md | 152 +++++++++++----------
1 file changed, 77 insertions(+), 75 deletions(-)
diff --git a/source/core-developers/execute-and-wait-interceptor.md
b/source/core-developers/execute-and-wait-interceptor.md
index e9ec02abb..9bf87ebef 100644
--- a/source/core-developers/execute-and-wait-interceptor.md
+++ b/source/core-developers/execute-and-wait-interceptor.md
@@ -8,34 +8,34 @@ parent:
# Execute and Wait Interceptor
-The ExecuteAndWaitInterceptor is great for running long-lived actions in the
background while showing the user a nice
+The ExecuteAndWaitInterceptor is great for running long-lived actions in the
background while showing the user a nice
progress meter. This also prevents the HTTP request from timing out when the
action takes more than 5 or 10 minutes.
-Using this interceptor is pretty straight forward. Assuming that you are
including struts-default.xml, this interceptor
-is already configured but is not part of any of the default stacks. Because of
the nature of this interceptor, it must
+Using this interceptor is pretty straight forward. Assuming that you are
including struts-default.xml, this interceptor
+is already configured but is not part of any of the default stacks. Because of
the nature of this interceptor, it must
be the `last` interceptor in the stack.
-This interceptor works on a per-session basis. That means that the same action
name (`myLongRunningAction`, in
+This interceptor works on a per-session basis. That means that the same action
name (`myLongRunningAction`, in
the above example) cannot be run more than once at a time in a given session.
On the initial request or any subsequent
-requests (before the action has completed), the `wait` result will be
returned.
+requests (before the action has completed), the `wait` result will be returned.
->The wait result is responsible for issuing a subsequent request back to the
action, giving the effect
+> The wait result is responsible for issuing a subsequent request back to the
action, giving the effect
> of a self-updating progress meter.
-If no `wait` result is found, Struts will automatically generate a wait result
on the fly. This result is written
-in FreeMarker and cannot run unless FreeMarker is installed. If you don't wish
to deploy with FreeMarker, you must
+If no `wait` result is found, Struts will automatically generate a wait result
on the fly. This result is written
+in FreeMarker and cannot run unless FreeMarker is installed. If you don't wish
to deploy with FreeMarker, you must
provide your own wait result. This is generally a good thing to do anyway, as
the default wait page is very plain.
-Whenever the wait result is returned, the action that is currently running in
the background will be placed on top
-of the stack. This allows you to display progress data, such as a count, in
the wait page. By making the wait page
+Whenever the wait result is returned, the action that is currently running in
the background will be placed on top
+of the stack. This allows you to display progress data, such as a count, in
the wait page. By making the wait page
automatically reload the request to the action (which will be short-circuited
by the interceptor), you can give
the appearance of an automatic progress meter.
-This interceptor also supports using an initial wait delay. An initial delay
is a time in milliseconds we let the server
-wait before the wait page is shown to the user. During the wait this
interceptor will wake every 100 millis to check
-if the background process is done premature, thus if the job for some reason
doesn't take to long the wait page is not
+This interceptor also supports using an initial wait delay. An initial delay
is a time in milliseconds we let the server
+wait before the wait page is shown to the user. During the wait this
interceptor will wake every 100 millis to check
+if the background process is done premature, thus if the job for some reason
doesn't take to long the wait page is not
shown to the user.
-This is useful for e.g. search actions that have a wide span of execution
time. Using a delay time of 2000 millis we
+This is useful for e.g. search actions that have a wide span of execution
time. Using a delay time of 2000 millis we
ensure the user is presented fast search results immediately and for the slow
results a wait page is used.
> Important: Because the action will be running in a separate thread, you
> can't use ActionContext because it
@@ -47,76 +47,78 @@ For example, the `search` action would run as a thread
named `searchBackgroundPr
## Parameters
- - `threadPriority` (optional) - the priority to assign the thread. Default is
`Thread.NORM_PRIORITY`.
- - `delay` (optional) - an initial delay in millis to wait before the wait
page is shown (returning `wait` as result code).
- Default is no initial delay.
- - `delaySleepInterval` (optional) - only used with delay. Used for waking up
at certain intervals to check if the background
- process is already done. Default is 100 millis.
+- `threadPriority` (optional) - the priority to assign the thread. Default is
`Thread.NORM_PRIORITY`.
+- `delay` (optional) - an initial delay in millis to wait before the wait page
is shown (returning `wait` as result
+ code). Default is no initial delay.
+- `delaySleepInterval` (optional) - only used with delay. Used for waking up
at certain intervals to check if the
+ background process is already done. Default is 100 millis.
## Extending the Interceptor
-If you wish to make special preparations before and/or after the invocation of
the background thread, you can extend
-the `BackgroundProcess` class and implement the `beforeInvocation()` and
`afterInvocation()` methods. This may be useful
-for obtaining and releasing resources that the background process will need
to execute successfully. To use your background
+If you wish to make special preparations before and/or after the invocation of
the background thread, you can extend
+the `BackgroundProcess` class and implement the `beforeInvocation()` and
`afterInvocation()` methods. This may be useful
+for obtaining and releasing resources that the background process will need to
execute successfully. To use your
+background
process extension, extend `ExecuteAndWaitInterceptor` and implement the
`getNewBackgroundProcess()` method.
## Examples
+### Example code 1
+
```xml
- <action name="someAction" class="com.examples.SomeAction">
- <interceptor-ref name="completeStack"/>
- <interceptor-ref name="execAndWait"/>
- <result name="wait">longRunningAction-wait.jsp</result>
- <result name="success">longRunningAction-success.jsp</result>
- </action>
+<action name="someAction" class="com.examples.SomeAction">
+ <interceptor-ref name="completeStack"/>
+ <interceptor-ref name="execAndWait"/>
+ <result name="wait">longRunningAction-wait.jsp</result>
+ <result name="success">longRunningAction-success.jsp</result>
+</action>
+```
+```html
<%@ taglib prefix="s" uri="/struts" %>
- <html>
- <head>
- <title>Please wait</title>
- <meta http-equiv="refresh" content="5;url=<s:url includeParams="all" />"/>
- </head>
- <body>
- Please wait while we process your request.
- Click <a href="<s:url includeParams="all" />"></a> if this page does not
reload automatically.
- </body>
- </html>
- </pre>
-
- <p><u>Example code2:</u></p>
- <p>
- This example will wait 2 second (2000 millis) before the wait page is shown
to the user. Therefore
- if the long process didn't last long anyway the user isn't shown a wait page.
- </p>
-
- <pre>
- <action name="someAction" class="com.examples.SomeAction">
- <interceptor-ref name="completeStack"/>
- <interceptor-ref name="execAndWait">
- <param name="delay">2000<param>
- <interceptor-ref>
- <result name="wait">longRunningAction-wait.jsp</result>
- <result name="success">longRunningAction-success.jsp</result>
- </action>
- </pre>
-
- <p><u>Example code3:</u></p>
- <p>
- This example will wait 1 second (1000 millis) before the wait page is shown
to the user.
- And at every 50 millis this interceptor will check if the background process
is done, if so
- it will return before the 1 second has elapsed, and the user isn't shown a
wait page.
- </p>
-
- <pre>
- <action name="someAction" class="com.examples.SomeAction">
- <interceptor-ref name="completeStack"/>
- <interceptor-ref name="execAndWait">
- <param name="delay">1000<param>
- <param name="delaySleepInterval">50<param>
- <interceptor-ref>
- <result name="wait">longRunningAction-wait.jsp</result>
- <result name="success">longRunningAction-success.jsp</result>
- </action>
- </pre>
+<html>
+<head>
+ <title>Please wait</title>
+ <meta http-equiv="refresh" content="5;url=<s:url includeParams='all' />"/>
+</head>
+<body>
+Please wait while we process your request.
+Click <a href="<s:url includeParams=" all" />"></a> if this page does not
reload automatically.
+</body>
+</html>
+</pre>
+```
+
+### Example code 2:
+This example will wait 2 second (2000 millis) before the wait page is shown to
the user. Therefore if the long process
+didn't last long anyway the user isn't shown a wait page.
+
+```xml
+<action name="someAction" class="com.examples.SomeAction">
+ <interceptor-ref name="completeStack"/>
+ <interceptor-ref name="execAndWait">
+ <param name="delay">2000</param>
+ </interceptor-ref>
+ <result name="wait">longRunningAction-wait.jsp</result>
+ <result name="success">longRunningAction-success.jsp</result>
+</action>
+ ```
+
+### Example code 3:
+
+This example will wait 1 second (1000 millis) before the wait page is shown to
the user.
+And at every 50 millis this interceptor will check if the background process
is done, if so
+it will return before the 1 second has elapsed, and the user isn't shown a
wait page.
+
+```xml
+<action name="someAction" class="com.examples.SomeAction">
+ <interceptor-ref name="completeStack"/>
+ <interceptor-ref name="execAndWait">
+ <param name="delay">1000</param>
+ <param name="delaySleepInterval">50</param>
+ </interceptor-ref>
+ <result name="wait">longRunningAction-wait.jsp</result>
+ <result name="success">longRunningAction-success.jsp</result>
+</action>
```
