Java Reference
In-Depth Information
MapComponent map = (MapComponent) component;
ResponseWriter writer = context.getResponseWriter();
writer.startElement("input", map);
writer.writeAttribute("type", "hidden", null);
writer.writeAttribute("name", getName(context,map), "clien-
tId");(
writer.endElement("input");
writer.endElement("map");
}
Notice that
encodeBegin
renders only the beginning
map
tag. The
encodeEnd
meth-
od renders the
input
tag and the ending
map
tag.
The encoding methods accept a
UIComponent
argument and a
javax.faces.context.FacesContext
argument. The
FacesContext
in-
stance contains all the information associated with the current request. The
UICompon-
ent
argument is the component that needs to be rendered.
The rest of the method renders the markup to the
javax.faces.context.ResponseWriter
instance, which writes out the markup
to the current response. This basically involves passing the HTML tag names and attribute
names to the
ResponseWriter
instance as strings, retrieving the values of the com-
ponent attributes, and passing these values to the
ResponseWriter
instance.
The
startElement
method takes a
String
(the name of the tag) and the component
to which the tag corresponds (in this case,
map
). (Passing this information to the
Re-
sponseWriter
instance helps design-time tools know which portions of the generated
markup are related to which components.)
After calling
startElement
, you can call
writeAttribute
to render the tag's at-
tributes. The
writeAttribute
method takes the name of the attribute, its value, and
the name of a property or attribute of the containing component corresponding to the at-
tribute. The last parameter can be null, and it won't be rendered.
The
name
attribute value of the
map
tag is retrieved using the
getId
method of
UICom-
ponent
, which returns the component's unique identifier. The
name
attribute value of
the
input
tag is retrieved using the
getName(FacesContext, UIComponent)
method of
MapRenderer
.
If you want your component to perform its own rendering but delegate to a renderer if
there is one, include the following lines in the encoding method to check whether there is
a renderer associated with this component:
