I wish to parse java source code files, and extract the methods source code.
I would need a method like this :
/** Returns a map with key = method name ; value = method source code */
Map<String,String> getMethods(File javaFile);
Is there a simple way to achieve this, a library to help me build my method, etc. ?
Download the java parser from https://javaparser.org/
You'll have to write some code. This code will invoke the parser... it will return you a CompilationUnit:
InputStream in = null;
CompilationUnit cu = null;
try
{
in = new SEDInputStream(filename);
cu = JavaParser.parse(in);
}
catch(ParseException x)
{
// handle parse exceptions here.
}
finally
{
in.close();
}
return cu;
Note: SEDInputStream is a subclass of input stream. You can use a FileInputStream if you want.
You'll have to create a visitor. Your visitor will be easy because you're only interested in methods:
public class MethodVisitor extends VoidVisitorAdapter
{
public void visit(MethodDeclaration n, Object arg)
{
// extract method information here.
// put in to hashmap
}
}
To invoke the visitor, do this:
MethodVisitor visitor = new MethodVisitor();
visitor.visit(cu, null);
You can build your parser with one of parser generators:
Also, you can use (or study how it works) something ready-made. There are Java Tree Builder which uses JavaCC and RefactorIt which uses ANTLR.
JavaCC is a "compiler-compiler" (parser generator) for Java. There are many grammar files for it, including one for Java 1.5.
I think you can use ANTLR parser generator.
It is very easy to use and ANTLR site has a lot of examples written in Java.
Also it comes with a plug-in for eclipse.
You can use this repo. https://github.com/minqukanq/method-extractor/blob/main/README.md
method-extractor is a parser for Java, Python.