OGO

Object Graph Programming (OGO) enables manipulating the JVM heap declaratively through queries. The queries are written using the Cypher Query Language. OGO supports two high-level modes, $OGO^{Neo}$ and $OGO^{Mem}$. The former serializes a sub-graph of the entire JVM heap object graph, loads it into a standalone Neo4J database and executes queries inside it. The latter executes queries in-memory (inside the native agent) using Antlr to parse the query and visitors to execute it Currently, $OGO^{Mem}$ is under construction and not all functionalities may work.

Examples

1. Searching an ArrayList for a given element.

   ArrayList<Long> lst = new ArrayList<Long>();
   lst.add(10L);
   lst.add(20L);
   lst.add(30L);
   query("MATCH ({$1})-[:elementData]->()-[]->({value : 20}) RETURN TRUE");

   In this example, we use imperative code to instantiate and add elements to an ArrayList and then use Cypher query through OGO to query lst to check if it contains element 20.

2. Implementing the containsKey method of java.util.HashMap class.

   public boolean containsKeyOgoImpl(HashMap map, object key){
      queryBool("MATCH ({$1})-[:table]->()-[]->()-[:key]->(n)"
               +"MATCH (m {$2})"
               +"WHERE n.`equals`(m)"
               +"RETURN COUNT(n) <> 0", map, key);
   }

   In this example, the first MATCH clause matches a pattern that collects all the objects corresponding to the key field of HashMap's inner class Node into the variable n. The second MATCH clause collects the given key object into the variable m. The WHERE clause filters the elements of n based on the output of the java.lang.Object class's equals method evaluating to true for pairwise inputs from n and m. This predicate is expected to filter number of elements of n to 1 if the given key is present in the map and to 0 if absent. Finally, we use the RETURN clause to return the value of the expression that compares equality of number of elements of n to 0. The query is hence expected to return true iff the number of elements in n is non-zero which is true only if the given key is contained in map.

Getting Started

Prerequisites

The project requires the following dependencies:

• Maven
• Java 21
• Conan 2.24.0
• CMake
• Clang Format

Installation

1. Install Dependencies

Run the installation script to automatically install all required dependencies:

./tasks.sh install_deps

This will check for and install any missing dependencies on your system.

Alternatively, verify your dependencies are correctly installed:

./tasks.sh check_deps

2. Build the Project

Compile the OGO project:

./tasks.sh compile

3. Full Installation

To compile and install the complete project:

./tasks.sh install

Running the Project

Run Tests

Execute the test suite:

./tasks.sh tests

Run the Application

Test out the OGO application by running it against Main.java

./tasks.sh exec

Format Code

Auto-format Java and C++ code according to project standards:

./tasks.sh format

End-to-End Setup

Perform a complete setup with dependency checks and full installation:

./tasks.sh end_to_end

Using OGO in a Maven Project

After packaging, OGO can be used in any maven project.

1. Include Client dependency:

   The client jar can be added as a dependency to a third-party project by adding the following to its pom.

   <dependency>
     <groupId>org.ogo</groupId>
     <artifactId>ogo</artifactId>
     <version>0.1.0</version>
     <scope>system</scope>
     <systemPath><!-- ENTER full path to client jar including jar name --></systemPath>
   </dependency>

2. Include Native Agent:

   The native agent can be included during execution by adding the following to the third-party pom.

   <configuration>
     <!-- for adding native agent ogoAgent -->
     <argLine>-agentpath:<!-- ENTER full path to native agent including native agent name --></argLine>
   </configuration>

   Some third-party project tend to use other plugins which may overwrite argLine. It may be necessary to explicitly specify this argument while running the tests using maven. This can be done using:

   mvn test -DargLine="-agentpath:<ENTER full path to native agent including native agent name>"

Citation

If you use OGO in your research, please cite the following paper:

@inproceedings{ThimmaiahETAL24OGO,
  author    = {Thimmaiah, Aditya and Lampropoulos, Leonidas and Rossbach, Christopher and Gligoric, Milos},
  title     = {Object Graph Programming},
  year      = {2024},
  doi       = {10.1145/3597503.3623319},
  booktitle = {International Conference on Software Engineering},
  pages     = {1--13},
}

The paper can be found here.