4.8.2 Compiling and Running a PGX Algorithm

To be able to compile and run a custom PGX algorithm, you must perform several actions:

1. Set two configuration parameters in the conf/pgx.conf file:
   • Set the graph_algorithm_language option to JAVA.
   • Set the java_home_dir option to the path to your Java home (use <system-java-home-dir> to have PGX infer Java home from the system properties).

   {
     "graph_algorithm_language": "JAVA",
     "java_home_dir": "<system-java-home-dir>"
   }

2. Create a session (either implicitly in the shell or explicitly in Java). For example:

   cd $PGX_HOME
   ./bin/opg4j

3. Compile a PGX Algorithm. For example:

   myAlgorithm = session.compileProgram("/path/to/MyAlgorithm.java")

4. Run the algorithm. For example:

   graph = session.readGraphWithProperties("/path/to/config.edge.json")
   property = graph.createVertexProperty(PropertyType.INTEGER)
   myAlgorithm.run(graph, property)