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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.
Содержание ColdFusion MX
Страница 1: ...Developing ColdFusion MX Applications...
Страница 22: ...22 Contents...
Страница 38: ......
Страница 52: ...52 Chapter 2 Elements of CFML...
Страница 162: ......
Страница 218: ...218 Chapter 10 Writing and Calling User Defined Functions...
Страница 250: ...250 Chapter 11 Building and Using ColdFusion Components...
Страница 264: ...264 Chapter 12 Building Custom CFXAPI Tags...
Страница 266: ......
Страница 314: ...314 Chapter 14 Handling Errors...
Страница 344: ...344 Chapter 15 Using Persistent Data and Locking...
Страница 349: ...About user security 349...
Страница 357: ...Security scenarios 357...
Страница 370: ...370 Chapter 16 Securing Applications...
Страница 388: ...388 Chapter 17 Developing Globalized Applications...
Страница 408: ...408 Chapter 18 Debugging and Troubleshooting Applications...
Страница 410: ......
Страница 426: ...426 Chapter 19 Introduction to Databases and SQL...
Страница 476: ...476 Chapter 22 Using Query of Queries...
Страница 534: ...534 Chapter 24 Building a Search Interface...
Страница 556: ...556 Chapter 25 Using Verity Search Expressions...
Страница 558: ......
Страница 582: ...582 Chapter 26 Retrieving and Formatting Data...
Страница 668: ......
Страница 734: ...734 Chapter 32 Using Web Services...
Страница 760: ...760 Chapter 33 Integrating J2EE and Java Elements in CFML Applications...
Страница 786: ...786 Chapter 34 Integrating COM and CORBA Objects in CFML Applications...
Страница 788: ......
Страница 806: ...806 Chapter 35 Sending and Receiving E Mail...