Major Description
When the method CreatePcj#withRyaIntegration is called, it creates the query metadata for Fluo and then populates Fluo with historical results form Rya. Before the metadata gets inserted, it's necessary to verify that the parsed query only consists of StatementPatterns, Joins, Leftjoins, Filters, and a Projection – these are the only nodes that currently have observers implemented. Right now there is a visitor which attempts to verify this – it has a meet method for each of the allowed node types – but it has no meet method for other node types that are not allowed so it just skips these nodes. So in effect, for a given query, this visitor goes through and creates metadata only for nodes that are allowed in Fluo, and ignores invalid nodes. The bug here is that if the user attempts to insert a query with an invalid query node into Fluo, this method will insert a different query into Fluo (the query obtained from the original by removing the invalid nodes). The input validation visitor should traverse the query, creating metadata, and either insert all of the metadata if the visitor traverses the entire query without encountering an invalid node, or throw an exception if an invalid node is an encountered.