What are filter classes?

Filters are implemented by subclasses of the RequestFilter class. Filter instances are created by the FilterFactory1 class utilizing methods of the RequestFilter class. All translation services apply filtering to the results returned from the query for dispatcher requests. To create a new filter, create a new subclass of the RequestFilter class providing an implementation for each of the methods specific to the new filter. A sample Filter.java file is provided in the DISP_ROOT/DispatcherClient/sample/integration/filters directory. RequestFilter contains the properties data member. The properties data member is an object that contains the configuration required and optional properties and values that are established when the dispatcher client starts. The RequestFilter contains the following methods: getRequiredPropertyNames This method is used by the FilterFactory class to return an array of property names of required configuration properties. These properties are those that must be specified by the filter configuration. If no value is specified for these properties, the FilterFactory class logs an error in the Extractor service instance log file and no filter instance is created. Copy public abstract String[] getRequiredPropertyNames(); getOptionalPropertyNames This method is used by the FilterFactory class to return an array of property names of optional configuration properties. These properties are optional. Copy public abstract String[] getOptionalPropertyNames(); setProperties This method is used by the FilterFactory class to allow a specific RequestFilter subclass access to property values. The subclass implementation must execute the super method. Copy public void setProperties(Properties p) throws Exception { properties = p; } filterRequest This method is used to filter dispatcher request objects for processing by the dispatcher client. It is run by the dispatcher client to filter the results of the query for dispatcher request for processing. Copy public abstract boolean filterRequest( IMANComponent request ) throws Exception; 1 FilterFactory is a class supplied by Dispatcher. It is a mechanism used by the service classes for creating instances of RequestFilter subclasses—for example, PriorityFilter.