Java Reference
In-Depth Information
Finally,
the
method
passes
the
message
to
the
constructor
of
javax.faces.validator.ValidatorException
.
When the error message is displayed, the format pattern will be substituted for the
{0}
in
the error message, which, in English, is as follows:
Input must match one of the following patterns: {0}
You may wish to save and restore state for your validator, although state saving is not
usually necessary. To do so, you will need to implement the
StateHolder
interface
in addition to the
Validator
interface. To implement
StateHolder
, you would
need to implement its four methods:
saveState(FacesContext)
,
re-
storeState(FacesContext, Object)
,
isTransient
, and
setTransi-
ent(boolean)
. See “
Saving and Restoring State
” on page
113
for more information.
Specifying a Custom Tag
If you implemented a
Validator
interface rather than implementing a managed bean
method that performs the validation, you need to do one of the following:
• Allow the page author to specify the
Validator
implementation to use with the
f:validator
tag. In this case, the
Validator
implementation must define its
own properties.
“
Using a Custom Validator
”
on page
132
explains how to use the
f:validator
tag.
• Specify a custom tag that provides attributes for configuring the properties of the
validator from the page.
To specify a custom tag, you need to add the tag to the tag library descriptor for the ap-
plication,
bookstore.taglib.xml
.
<tag>
<tag-name>formatValidator</tag-name>
<validator>
<validator-id>formatValidator</validator-id>
<validator-
class>dukesbookstore.validators.FormatValidator</validator-class>
</validator>
</tag>
The
tag-name
element defines the name of the tag as it must be used in a Facelets page.
The
validator-id
element identifies the custom validator. The
validator-class
element wires the custom tag to its implementation class.
