[EDGENT-311] support SELECT without any parameters in JdbcStreams

• Type: Improvement
• Status: Closed
• Priority: Minor
• Resolution: Not A Problem
• Affects Version/s: Apache Edgent 1.0.0
• Component/s: Connectors
• Assignee: Unassigned
• Reporter: Rui Shen
• Created: 11/Nov/16 04:09
• Updated: 28/Nov/16 21:37
• Resolved: 28/Nov/16 21:37

Description

Now I am trying to run a SELECT statement without parameters (e.g "select id,name,age from person") using JdbcStreams. But I found there is no straightforward way to do this. Looks like the APIs of JdbcStreams is designed for only prepared statement with parameters .
However, I found a workaround to make this - always create a TStream with one tuple but in the ParameterSetter, does nothing. Although this works, it looks uncomfortable. Are you going to support this in the future release?

Topology t = this.newTopology("testSelect_WithParameters");
JdbcStreams db=new JdbcStreams(ds,(ds)=>

{ds.getConnection()}

);
TStream<String> stream=t.collection(Arrays.asList(new String[]

{"dummy"}

)); // to execute the sql, always needs to create a TStream containing one tuple.
ParameterSetter<String> paramSetter=(s,stmt)->{}; //do nothing here
ResultsHandler<Object[], JsonObject> rh = (tuple, rs, exc, consumer) -> {};
db.executeStatement(stream, "select id,name,age from person", paramSetter,rh);