Github user mattyb149 commented on a diff in the pull request: https://github.com/apache/nifi/pull/2443#discussion_r170032821 --- Diff: nifi-nar-bundles/nifi-mongodb-bundle/nifi-mongodb-processors/src/main/java/org/apache/nifi/processors/mongodb/GetMongo.java --- @@ -226,6 +242,11 @@ private ObjectWriter getObjectWriter(ObjectMapper mapper, String ppSetting) { @Override public void onTrigger(final ProcessContext context, final ProcessSession session) throws ProcessException { + FlowFile input = session.get(); + if (!context.hasIncomingConnection() && (context.getProperty(QUERY) == null)) { + throw new RuntimeException("Without an incoming connection, the Query property must be set."); --- End diff -- The RuntimeException here and on line 276 should be ProcessException, it's a NiFi-specific runtime exception that indicates we realize something went wrong but we don't know how to handle any input/output we might have (like routing to failure). Also rather than `context.getProperty(QUERY) == null` since there will be a PropertyValue object returned, you should use `context.getProperty(QUERY).isSet()`.
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