org.metawidget.inspector.faces.UiFacesAttribute Maven / Gradle / Ivy
// Metawidget
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
package org.metawidget.inspector.faces;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
/**
* Annotates an arbitrary Metawidget attribute, based on a Java Server Faces EL expression.
*
* Unlike UiFacesLookup, which fits into a well-defined place within the JSF framework
* (ie. f:selectItems), the UiFacesAttribute expression is evaluated by
* the Inspector, not by the Metawidget. This means the
* Inspector must be able access to FacesContext. In practice this usually
* happens automatically, but in some cases it may be necessary to 'combine remote inspections' (see
* the Reference Documentation).
*
* Note in the event UiFacesAttribute uses an attribute name overlapping with another
* UiFacesxxx annotation (eg. UiFacesLookup) the latter will get
* precedence. For example...
*
*
* @UiFacesLookup( "#{foo}" )
* @UiFacesAttribute( name = FacesInspectionResultConstants.FACES_LOOKUP, expression =
* "#{!empty bar ? '' : null}" )
*
* ...in general, you should avoid such ambiguous situations. For example, you could instead use...
*
*
* @UiFacesAttribute( name = FacesInspectionResultConstants.FACES_LOOKUP, expression =
* "#{!empty bar ? '' : '#{foo}'}" )
*
* Also consider using FacesInspectorConfig.setInjectThis.
*
*
* @author Richard Kennard
*/
@Retention( RetentionPolicy.RUNTIME )
@Target( { ElementType.FIELD, ElementType.METHOD } )
public @interface UiFacesAttribute {
/**
* Attribute to set.
*
* Multiple attributes can be specified if you need to set multiple attributes to the same
* expression.
*/
String[] name();
/**
* Value to set the attribute to. Must be an EL expression of the form #{...}.
*
* Note EL expressions can include conditions. For example:
*
* #{foo.bar ? 'baz' : null}.
*
* Also consider using FacesInspectorConfig.setInjectThis.
*/
String expression();
}