VOID expressions return no value but are used to
perform other work. The
VOID EXPORT_PROP expression writes a given property to a
file and replaces the property value with the value of the newly created file’s
URL.
Writing a property value to a file is useful when the property is a
long text description. You can save memory by writing the property to a file
and accessing the file only when necessary via the new URL property value. You
can use
VOID REMOVE_EXPORTED_PROP to delete this file and the
property pointing to the file.
The property to export can be specified in either one of the following ways:
Use the
PROP_NAMEexpression node to specify the name of the property to export.Use a
STRINGexpression to generate the name of the file to export. This mode is useful when crawling files: the file name is generated using aSTRING DIGESTof theEndeca.Identifierproperty and the expression generates a different file name for each URL identifier.
The following expression nodes can modify
EXPORT_PROP:
See the
EXPRESSION element for DTD and attribute information.
This example exports properties Prop1 and Prop2 from the props directory.
<EXPRESSION TYPE="VOID" NAME="EXPORT_PROP"> <EXPRNODE NAME="PROP_NAME" VALUE="Prop1"/> <EXPRNODE NAME="PROP_NAME" VALUE="Prop2"/> <EXPRNODE NAME="URL" VALUE="props"/> <EXPRNODE NAME="PREFIX" VALUE="out."/> </EXPRESSION>
