Base class of all field definition classes.
Type-specific classes are derived from this class to define specific
per-type behaviours. This class also provides default behaviours for when
a specific type cannot be loaded.
Construct a new FieldDefinition. Parameters are passed in a hash. See
Form.pm for how it is called. Subclasses should pass @_ on to this class.
Break circular references.
isEditable() -> $boolean
Is the field type editable? Labels aren't, for example. Subclasses may need
to redefine this.
isMultiValued() -> $boolean
Is the field type multi-valued (i.e. does it store multiple values)?
Subclasses may need to redefine this.
isTextMergeable() -> $boolean
Is this field type mergeable using a conventional text merge?
isMandatory() -> $boolean
Is this field mandatory (required)?
renderForEdit( $web, $topic, $value ) -> ($col0html, $col1html)
$web - the web containing the topic being edited
$topic - the topic being edited
Render the field for editing. Returns two chunks of HTML; the
$col0html is appended to the HTML for the first column in the
form table, and the
$col1html is used as the content of the second column.
@classes) - $classes"> cssClasses(@classes) -> $classes
Construct a list of the CSS classes for the form field. Adds additional
class specifiers related to the attributes of the field e.g mandatory.
Pass it a list of the other classnames you want on the field.
getDefaultValue() -> $value
Try and get a sensible default value for the field from the
values stored in the form definition. The result should be
a value string.
Some subclasses may not support the definition of defaults in
the form definition. In that case this method should return
renderHidden($meta) -> $html
Render the form in
$meta as a set of hidden fields.
populateMetaDataFromQuery( $query, $meta, $old ) -> ($bValid, $bPresent)
Given a CGI
$meta object, and an array of
$old field entries,
then populate the $meta with a row for this field definition, taking the
content from the query if it's there, otherwise from $old or failing that,
from the default defined for the type. Refuses to update mandatory fields
that have an empty value.
Return $bValid true if the value in $meta was updated (either from the
query or from a default in the form.
Return $bPresent true if a value was present in the query (even it was undef)
ObjectMethod *renderForDisplay ($format,$attrs) -> $html
Render the field for display, under the control of $attrs.
The following vars in $format are expanded:
$title - title of the form field
$value - expanded to the protected value of the form field
The value is protected by TWiki::Render::protectFormFieldValue.