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<v Narrator>Hey, welcome back.</v>

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In this video, I'm gonna show you how to use

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managed bean scopes.

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So we'll cover the following topics.

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We'll first define the scopes for managed beans,

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and then we'll discuss application scope.

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Next, we'll discuss session scope.

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And then finally, we'll wrap it up with the request scope.

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Okay, so a lot of good topics here.

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Let's get started.

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Okay, so what I'm gonna do is cover

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the most commonly used scopes.

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So we'll start off with the request scope.

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Request scope is used on a per-web request.

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It's short-lived.

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We'll also talk about session scope

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that's unique for a given user,

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and then we'll also look at application scope.

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And this scope is shared by all users.

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Now, there are also some other scopes

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that are available in JSF,

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and I'll list them here on this next slide.

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So here's a list of all of the scopes in JSF.

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Now, I don't want to overwhelm you

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with all this information.

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We'll simply cover the first three,

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because the first three are the most commonly used:

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request, session, and application.

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However, I wanted to show you

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that there are other scopes available

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just for completeness.

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However, we won't go into any details

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on those additional scopes.

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If you would like, you can pause the video here,

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and go research those other scopes.

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However, we'll use the most commonly used scopes:

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request, session, and application.

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Now, let's take a look at the first scope here.

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Application scope.

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Now application scope is a bean that's created once

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for all application users,

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and it's commonly used to share

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an instance of a utility class.

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For example, when we get into database development,

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it's the primary use for keeping track

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of our database utility class.

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And we'll actually use it later on in the course

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when we get into database development.

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However, I will show you a short example

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of the application scope in this video,

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just so you can see how it works in general.

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So in this example, what we'll do

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is make use of application scope.

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And I want to create a very simple example.

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It's gonna have a form that's gonna interact with the bean.

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And all it's gonna do

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is simply increment the value of a bean,

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so the bean will simply have a counter

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that will increment the value

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each time we click on the form button.

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So over in the bottom light here,

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we have this counter_two.xhtml.

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That's the actual HTML or JSF HTML

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that we'll use to render this form.

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So we'll have a command button,

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we have a value for increment,

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and the action is counterTwo.increment.

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So it's gonna call it increment method

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on our counter two bean.

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So now let's take a look at this counter two bean

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on the next slide.

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So here's our counter two bean.

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This bean will have application scope.

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So note here, when we settle the coding for it,

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we add a new annotation here,

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and this is something that's new,

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so after managed bean,

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we also say @ApplicationScoped.

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So what this means is that this bean

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will be created once in the application

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and shared by all users,

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and it will kind of exist

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while all users are in there using it.

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So it's kind of like global data.

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So whenever we call increment,

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it's gonna increment the value of this bean.

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Again, it's only created once,

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and it's shared by all users.

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Now let's go ahead and look at a demo here

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of the application scope.

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So I'll move back into Eclipse.

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I'll make use of an existing project

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from the previous video, bean-demo,

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and again, this code is also available

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in the downloads from earlier in the course.

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I'll expand the window here for web content.

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And I'll take a look at this file here,

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counter_two.xhtml.

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Now this is just a very simple page

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that we're gonna use for testing the application scope.

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On line 17, I'm simply gonna print out

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the actual value of the counter bean.

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And then lines 21 through 24,

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I have my command button or my form.

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So on line 23, I have action, counterTwo.increment.

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So I'm gonna call it the increment method

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on my counter two bean.

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Okay, so let's go ahead and look

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at the actual bean for counter two.

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So I move to my Java Resources,

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down to source.

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I'll choose CounterTwo.java.

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I'm gonna go ahead and expand this window here

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so I can see more of the code.

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So, on lines 6 through 8,

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we're gonna have this CounterTwo.

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It's a managed bean,

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and on line 7, we make it application scope.

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So that means that it's gonna be used or shared

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by all users of the application.

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Application scoped.

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On line 10, I have a value that's initialized to zero.

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And then here's that actual method

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that's called by the form,

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so it will simply say CounterTwo.increment.

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So on line 13, we have value++,

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basically increments the value by one.

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It's the same thing as saying value equals value plus one.

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Finally, we return student_two,

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the name of the actual page

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or the form that we want to show.

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Well, now let's go ahead and run the application.

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So I'll choose this file here, counter_two.xhtml.

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And what I'll do is I'll right-click,

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and I'll say Run As,

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and I'll choose Run on Server.

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So once the application runs,

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I have the basic page here,

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Counter Two Application Scope Test.

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What I'd like to do is actually look at this

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in a regular web browser.

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So I'm simply gonna copy this URL,

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just a right-click and choose copy,

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and then what I want to do

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is open up a FireFox browser and a Chrome browser.

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So in my FireFox browser,

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I dropped in the actual value here for the URL,

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and it's our test,

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and I simply hit the increment button a couple times,

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and the value's incrementing as desired.

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Now let me copy this URL one more time,

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and bring up my Chrome browser.

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So in the Chrome browser, I'll drop in the URL,

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so counter_two.xhtml.

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And one thing to note here

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is that even in the Chrome browser,

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the counter value starts at seven.

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Why? Because this bean is being shared application-wide.

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So even if I make any changes to that bean,

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it's being shared by any user of the application

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or all users of the application.

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Now let me resize this a bit,

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and put it side-by-side,

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just we can kind of see it in action.

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So just give me one second to line these windows up.

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All right, so now I have the windows lined up.

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On the left-hand side, I have the FireFox browser.

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We can do an increment.

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And then over on the right-hand side,

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I have the Chrome browser,

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so a different browser.

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But again, note here,

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this bean is being shared by all users,

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so note, you make any changes in one browser,

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the same change is reflected in the other browser.

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So again, the single bean,

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multiple users are making use of that bean.

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So we'll actually use this for sharing a common object,

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such as a database utility class.

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And we'll cover that

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when we get into the database section of the course.

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So there is a valid use case for this.

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And we'll see it when we make it

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to the database section of the course.

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Hey. So this video's going a little bit long,

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so what I'm gonna do

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is actually break it up into two separate videos.

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So we just finished information on application scope.

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In the next video, I'm gonna pick up,

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and we'll cover session scope and request scope.

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So I'll see you in the next video

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for session and request scope.