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PropertTester [message #480720]

Tue, 18 August 2009 10:09

Jeeeyul Lee

Messages: 117
Registered: July 2009
Location: Seoul

Senior Member

Why Property tester Expression Node does not resolve actual value while
expression runs.

in complex environment, that's not easy to determine point when property
changes.

For example: in word processor, bold state of current text selection.
in this case, we have to call requestEvaluation so many times to use
menu contribution.

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Re: PropertTester [message #480830 is a reply to message #480720]

Tue, 18 August 2009 15:45

Paul Webster

Messages: 6859
Registered: July 2009
Location: Ottawa

Senior Member

The property tester does resolve its value every time the expression is run. Do you mean why do you have to call requestEvaluation(*) when you know your property has changed? Because in any event driven system, something has to create and feed the events into the system.

When using an AbstractSourceProvider to provide a variable (for use with "with" elements) to the evaluation service, the ASP fires events into the system (basically hooking up the client eventing mechanism to the system). When you use a property tester/property, you must hook up your known eventing mechanism to the system.

PW

Paul Webster
http://wiki.eclipse.org/Platform_Command_Framework
http://wiki.eclipse.org/Command_Core_Expressions
http://wiki.eclipse.org/Menu_Contributions

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Thanks! (no contents) [message #480932 is a reply to message #480830]

Wed, 19 August 2009 01:39

Jeeeyul Lee

Messages: 117
Registered: July 2009
Location: Seoul

Senior Member

I told you.

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Re: Thanks! (no contents) [message #481036 is a reply to message #480932]

Wed, 19 August 2009 12:07

Paul Webster

Messages: 6859
Registered: July 2009
Location: Ottawa

Senior Member

"I told you" what, exactly?

You started your post with: "Why Property tester Expression ..." a question. My post was answering your question. So what did you tell me? That you noticed the same thing in your example? Yes, true, but you asked why ... hence my post.

PW

Paul Webster
http://wiki.eclipse.org/Platform_Command_Framework
http://wiki.eclipse.org/Command_Core_Expressions
http://wiki.eclipse.org/Menu_Contributions

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Re: Thanks! (no contents) [message #481180 is a reply to message #481036]

Thu, 20 August 2009 01:06

Jeeeyul Lee

Messages: 117
Registered: July 2009
Location: Seoul

Senior Member

ooops, "I told you" just means "no contents" in subject.

I told you "no content" in subject because I don't want someone try to
click that post to read, To prevent wasting their time. In Korea, that's
general expression.

I'm sorry if it made you feel bad.

Paul Webster wrote:
> "I told you" what, exactly?
>
> You started your post with: "Why Property tester Expression ..." a
> question. My post was answering your question. So what did you tell
> me? That you noticed the same thing in your example? Yes, true, but
> you asked why ... hence my post.
>
> PW
>

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