Use of the Iterator Component¶
The Extractor component returns a list of records, each one containing one extracted data record. In our example, each record contains information about one e-mail message with its sender, message, date and size fields.
The Iterator component is used to iterate on each record from an input list. In each iteration, the component will return a record from the list.
As usual, the iteration component can be dragged from the browsing area or from the workspace component bar. The component icon is . Rename de component to “MainPageIterator” and its output to “WEBMAIL”. The figure below shows the graphic appearance of the component in the workspace. This component is represented using one start box and one end box. The portion of the workflow between the start and the end boxes will be executed in each iteration.
The configuration of this component is very simple. First, select the input list to feed the iteration process. In this case, as can be seen in the above figure, the list corresponds to the extraction component output described in section Configuration of the Extractor Component, EXTRACTIONOUTPUT.
The Iterator component wizard allows configuring whether iterations should be processed in parallel or not. If parallel execution is selected you can configure the maximum number of concurrent iterations.
Regarding the error configuration, in addition to the Runtime Error explained in that section, the Iterator component adds the Inner Component error. This error occurs in a compound component (Iterator, Form Iterator, Loop, Repeat and Next Interval Iterator) when some of its inner components fails. This error can be handled by raising it or continuing processing the remaining iterations although an error occurs in the current one. Besides, the actions Trace Record and Output Record (see section Error Processing On the Web Browsing Automation) can be executed with this type of error.