Implementing a custom QueryFunction class

To implement your new QueryFunction, you must:

• Add private filter or configuration properties.
• Create getters and setters for any filter properties you add.
• Define a no-argument constructor (protected access modifier optional, but recommended).
• Implement the applyToDiscoveryServiceQuery method.
  This method is called with the following arguments:

  • The Conversation Service query
  • A stateName string

  Your custom function should use the Conversation Service API to apply itself to the conversation service query argument.

  The stateName argument provides the value to use for state name references in Conversation Service filters or content element configs that your custom function adds to the query.

• Implement the toString method, which is used to compare QueryFunction instances for equality.

  toString should be consistent and deterministic in order to accurately determine if two instances of your custom QueryFunction are identical or distinct.

• Optionally, implement the beforeQueryStateAdd(QueryState state) method to check the current query state before the function is added.