JavaDataFlow

Creating Data Flow Graphs from java input classes

With JavaDataFlow you can create data flow graphs. This is a directed graph where a node represents data (e.g. fields, inputParameters, etc.) and the edges represent a node influencing the state of another node. Nodes are always defined within a specific method, constructor, codeBlock. We refer to such a code block as owner. Every Node has an owner. Every owner can also have an owner, for instance a method is owned by a class.

Example

Let's say we have a class as given as below:

public class JavaDataFlowExampleInputClass {
  int a;
  public int getA() {
    return a;
  }
  public void setA(int inputA) {
    this.a = inputA;
  }
}

Then we can execute the following commands to create a data flow graph from it. First define the path to your project and setup the path where JavaDataFlow will look for class files. If you have multiple projects where JavaDataFlow needs to look for class files, you can enter multiple project paths there. Then create the data flow graph using the absolute input path to the java class. A DataFlowGraph represents a single class.

String projectPath = "projectPath";
String input = "/relativePath/Example.java";
StaticJavaDataFlow.getConfig().setProjectPaths(projectPath);
DataFlowGraph dfg = JavaDataFlow.create(projectPath + input);

Now if we want to gather all input nodes to this class that can influence the output of the method "getA", we can do that as given below. First get the given method. Now we need to walk back until we reach a node that is an input parameter of a method, for this we can use the method DataFlowNode::isInputParameter. For this example we don't want to go outside of this class so we add dfg::owns as scope to the method walkBackUntil. The scope determines when to stop walking over the nodes, this can become important if multiple data flow graphs are connected to each other. However, this is currently not supported yet.

DataFlowMethod getA = dfg.getMethods().stream().filter(m -> m.getName().equals("getA")).findFirst().get();
List<DataFlowNode> inputNodes = getA.getReturnNode().get().walkBackUntil(DataFlowNode::isInputParameter, dfg::owns);
System.out.println(inputNodes.get(0).getName());

The above code will output the name "inputA".

Setup

Add the dependency below to the pom of your project.

<dependency>
  <groupId>com.github.daanvdh.javadataflow</groupId>
  <artifactId>JavaDataFlow</artifactId>
  <version>0.0.2</version>
</dependency>

Definitions

The owner of a DataFlowNode represents structure in which the node is defined. For the method setA, the parameter inputA has a ParameterList as input. The ParameterList has the DataFlowMethod for "setA" as owner. The owner of the method is the DataFlowGraph representing Example.java

Features

JavaDataFlow uses JavaParser for parsing the input classes. Each DataFlowNode has a representedNode which is the JavaParser Node that it represents. If you have a given JavaParser Node you can get the JavaDataFlowNode via DataFlowGraph::getNode.

Roadmap

Include Constructors in the JavaDataFlow graph.
Model if statements.
Model primitive functions like: + - * / < >.
Model for and while loops.
Connect multiple JavaDataFlow graphs to each other so that we can walk from class to class.

License

JavaDataFlow is available under the terms of the Apache License. http://www.apache.org/licenses/LICENSE-2.0