Create a custom query preprocessor
A query preprocessor modifies the native SolrQuery object right before it is sent to the Solr server for processing.
Procedure
- Create a class that does the following actions:
- Extends from the AbstractSolrSearchQueryPreprocessor class, and
- Implements the SearchQueryPreprocessor interface.
- Implement the constructor method, which takes a component identifier as a string input parameter. Typically, component-specific logic is initialized here.
- Implement the invoke method, which takes the SelectionCriteria object and an object array as input parameters. This SelectionCriteria object is a Java representation of the original search expression, where search criteria is stored as a control parameter object. The object array contains the native SolrQuery object, which is initialized by:
super.invoke(selectionCriteria, queryRequestObjects);Two instance variables can be used:
- iSelectionCriteria
- Java representation of the original search expression.
- iSolrQuery
- Java representation of native search query request objects.
- Helper methods are available from its abstract class, which can be used for retrieving from the control parameters:
String term = getControlParameterValue(SearchServiceConstants.CTRL_PARAM_SEARCH_TERM);
For a list of supported control parameters, see WebSphere Commerce Search interface.
For more information about the default query preprocessors, see WebSphere Commerce Search configuration file (wc-search.xml).
Example
The following download contains a code sample for creating a custom query preprocessor: