MACROMEDIA COLDFUSION MX 61-DEVELOPING COLDFUSION MX, Develop Manual

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256 Chapter 12: Building Custom CFXAPI Tags
Response object
The Response object is passed to the
processRequest
method of the CustomTag interface. The
following table lists the methods of the Response object for writing output, generating queries,
and setting variables within the calling page:
For detailed reference information on each of these interfaces, see CFML Reference .
Query object
The Query object provides an interface for working with ColdFusion queries. The following table
lists the methods of the Query object for retrieving name, row count, and column names and
methods for getting and setting data elements:
For detailed reference information on each of these interfaces, see CFML Reference .
Loading Java CFX classes
Each Java CFX class has its own associated ClassLoader that loads it and any dependent classes
also located in the
web_root /WEB-INF/classes directory. When Java CFX classes are reloaded
after a change, a new ClassLoader is associated with the freshly loaded class. This special behavior
is similar to the way Java servlets are handled by the web server and other servlet engines, and is
required in order to implement automatic class reloading.
However, this behavior can cause subtle problems when you are attempting to perform casts on
instances of classes loaded from a different ClassLoader. The cast fails even though the objects are
apparently of the same type. This is because the object was created from a different ClassLoader
and therefore is not technically the same type.
To solve this problem, only perform casts to class or interface types that are loaded using the
standard Java classpath, that is, classes not located in the classes directory. This works because
classes loaded from outside the classes directory are always loaded using the system ClassLoader,
and therefore, have a consistent runtime type.
Method Description
write Outputs text to the calling page.
setVariable Sets a variable in the calling page.
addQuery Adds a query to the calling page.
writeDebug
Outputs text to the debug stream.
Method Description
getName
Retrieves the name of the query.
getRowCount
Retrieves the number of rows in the query.
getColumns
Retrieves the names of the query columns.
getData
Retrieves a data element from the query.
addRow
Adds a new row to the query.
setData
Sets a data element within the query.