MACROMEDIA COLDFUSION 4.5-CFML LANGUAGE Manual do Utilizador descarregar pdf (Página 10)

10 CHAPTER 30 Extending ColdFusion with CFX

For instance, the tag can be called as shown in the following code snippet. The resulting message

will incorporate the words

Belinda and 19, just as you would expect (Figure 30.1):

<CFX_HelloWorld

NAME=”Belinda”

AGE=”19”>

Of course, you can provide dynamic expressions to the tag’s attributes, just like any native CFML

tag. For instance, you could supply values from the

SESSION and FORM scopes like so:

<CFX_HelloWorld

NAME=”#SESSION.FirstName#

AGE=”#FORM.Age#”>

If a ColdFusion page tries to call the tag without supplying the NAME or AGE attributes, an exception

will be thrown, resulting in a standard error message (Figure 30.2).

Understanding the Java Code

Even though it’s a very simple example, I’d like to spend a few moments going over a few key ele-

ments of the

<CFX_HelloWorld> source code. For starters, take another look at the ﬁrst few lines of

the example (Listing 30.1); these are the lines that make it possible for ColdFusion to treat the class

as a CFX tag.

Figure 30.2

An error message is

displayed if required

attributes are not

provided.

Figure 30.1

The <CFX_

HelloWorld>

tag

accepts two attributes

and displays their

values in a simple text

message.

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MACROMEDIA COLDFUSION 4.5-CFML LANGUAGE Manual do Utilizador Página 10