These files serve to illustrate how you can interoperate with CQL generated code in Java.

• ./CGSQLMain.java

This is just a simple main program that creates the result set and then prints it out. It's not especially reusable but we need a main so here it is.

• ./TestResult.c
• ./TestResult.h
• ./TestResult.java

This is the JNI class that runs the particular stored procedure we need in this sample. See Sample.sql below. The native code has to

• open a database
• call the stored procedure with any args (there are none other than the database in this example)
  • for any real code this would need to be generalized
• close the database

The general purpose classes and the compiler output concern themselves with allowing result sets to be accessed from Java. There is no general way to invoke stored procedures with arbitrary signatures at this time. Though you could imagine using the JSON output to codegen JNI wrappers as well as result set readers. This area is ripe for future development to make Java access easier.

• ./com_facebook_cgsql_CQLResultSet.c
• ./com_facebook_cgsql_CQLResultSet.h
• ./com/facebook/cgsql/CQLResultSet.java
• ./com/facebook/cgsql/CQLViewModel.java

These are the re-usable parts. CQLResultSet uses standard JNI methods to read the primitive types out of any result set. The compiler produce a subclass of CQLViewModel that uses CQLResultSet to do its job. The JNI C file com_facebook_cgsql_CQLResultSet.c has the necessary calls to the runtime to do that reading. Each of the functions is just a few lines of code. The .h file is auto-generated by java -h from the .java and hence doesn't actually need to be checked in but it's included because it's useful to browse without building and any diffs might be interesting in further porting efforts.

• ./Sample.sql

This is is a stored procedure that creates a table, puts stuff in it, and then returns its contents. This is in some sense the core of the demo. Everything else is scaffolding.

• ./make.sh
• ./clean.sh

Use make.sh to build and execute the JNI demo. Use clean.sh to clean up the build artifacts afterwards.

Build notes:

• set CGSQL_GCC=1 if you're using GCC rather than clang
• set JAVA_HOME to the location of your JDK, for jni.h and friends.
• set SQLITE_PATH to the location of your SQLite installation if you want to use an amalgam build of SQLITE rather than just use -lsqlite3

make.sh is itself pretty straightforward