Eclipse create CompilationUnit from .java file

Question

How can I load a .java file into a CompilationUnit? For example, lets say I have a A.java file in my current project. I would like to load it into a CompilationUnit and then pass it to the ASTParser. It is not an option just to load it as a plain text since it seems that in that case I will not get the binding information in the AST.

Thermochemistry

Answer 1

You can load the projects using jdt and eclipse core libraries.

Using the following code you can load all the projects in the workspace.

IWorkspace workspace = ResourcesPlugin.getWorkspace();
IWorkspaceRoot root = workspace.getRoot();
// Get all projects in the workspace
IProject[] projects = root.getProjects();

Then you can get packages and in turn the java files.

IPackageFragment[] packages = JavaCore.create(project).getPackageFragments();
IPackageFragment mypackage = packages.get(0); // implement your own logic to select package
ICompilationUnit unit = mypackage.getCompilationUnits();

Then you can use this ICompilationUnit object for getting the CompilationUnit

ASTParser parser = ASTParser.newParser(AST.JLS3); 
parser.setKind(ASTParser.K_COMPILATION_UNIT);
parser.setSource(unit);
parser.setResolveBindings(true);
CompilationUnit cUnit = parser.createAST(null);

This CompilationUnit object can be passed on to the ASTParser.

Senator

This will work only for Eclipse projects? I.e., it will not work for Java projects? – Thermochemistry

You cannot use JDT in java projects by having jar files. To use JDT, you need to have the program running as a plug-in (or at least, an OSGi-enabled application). – Senator

Ok, so I can load the .java file to CompilationUnit by this approach only for eclipse projects. FYI, it is possible to use JDT outside of the eclipse projects by using setSource(char[]) and setEnvironment methods. (from version 3.6) – Thermochemistry

@bellpeace well i am using ver 3.5.1 . Its nice to know the JDT team have included the support outside eclipse env in their new version. May be i will try it out. Thanks for the info anyway. – Senator

@prosseek you can loop through the packages [IPackageFragment array] and get the package. mypackage is of Type IPackageFragment. – Senator

You can use the Eclipse JDT Language Server to enable code assistant features, without having to setup an Eclipse project manually: https://mcmap.net/q/1816239/-eclipse-jdt-how-to-get-data-model-for-java-content-assist – Flaming