Information sources usually allow a
limited number of query forms to be submitted. The Input defines the set of queries
acceptable
to a particular source. it consists of a set of variables that a user can associate values
with, and their corresponding range
specification. For example, suppose we had the following input interface at
AmazonSearch:
To get information about books, we have to enter a query in the form of a string and we have to select a search mode from the drop down box. Hence, the INPUT for AnazonSearch would be written as follows:
<INPUT>
<elementType id="amazonQuery"> <string/>
</elementType>
<elementType id="amazonMode">
<attribute name="searchMode"
atttype="ENUMERATION"
values="books music classical video toys
electronics blended" />
</elementType>
</INPUT>
In this INPUT, amazonQuery represents the keyword that is entered into the box and amazonMode is the mode selected from the drop down box.