Eclipse JDT ASTVisitor - how to tell if a field is read or written in a method?

Question

I am writing a Eclipse ASTVisitor. How to tell if a field is read or written in a method?

The idea provided was "You need to vist Assignment node. Field on the LHS is written, while fields on the RHS expression is read."

After I visit the assignment and get the LHS and RHS which are both of Expression, how do I tell if the Expression contains the field?

Answer 1

If you are doing AST work, I suggest working with the AST View plugin. It is a very handy tool for understanding the JDT AST.

Your approach will work. I use a variable inside the visitor to indicate I'm in an assignment.

    public boolean visit(final Assignment node) {
 inVariableAssignment = true;
 node.getLeftHandSide().accept(this);
 inVariableAssignment = false;
 node.getRightHandSide().accept(this);
 return false;
}

Now, when visiting a SimpleName or a QualifiedName I do something like:

    public boolean visit(final SimpleName node) {
 if (!node.isDeclaration()) {
  final IBinding nodeBinding = node.resolveBinding();
  if (nodeBinding instanceof IVariableBinding) {
   ...
  }
 }
 return false;
}

The ellipsis (...) will be replaced by a code which handles the field access according to the value of your inVariableAssignment. This will get you started.

Oh, don't forget PostfixExpression and PrefixExpression...