What is the correct way to parse variables using JavaParser?

Question

Using JavaParser I can get a list of my methods and fields using:

//List of all methods
System.out.println("Methods: " + this.toString());
List<TypeDeclaration> types = n.getTypes();
for (TypeDeclaration type : types)
{
    List<BodyDeclaration> members = type.getMembers();
    for (BodyDeclaration member : members)
    {
        if (member instanceof MethodDeclaration)
        {
            MethodDeclaration method = (MethodDeclaration) member;
            System.out.println("Methods: " + method.getName());
        }
    }
}

//List all field variables.
System.out.println("Field Variables: " + this.toString());
List<TypeDeclaration> f_vars = n.getTypes();
for (TypeDeclaration type : f_vars)
{
    List<BodyDeclaration> members = type.getMembers();
    for (BodyDeclaration member : members)
    {
        if (member instanceof FieldDeclaration)
        {
            FieldDeclaration myType = (FieldDeclaration) member;
            List <VariableDeclarator> myFields = myType.getVariables();
            System.out.println("Fields: " + myType.getType() + ":" + myFields.toString());
        }
    }
}

But I can't figure out how to get a list of my variables. I simply want a list of all variables from a java source, regardless of scope.

If you have found the answer to your question, don't edit it: feel free to answer it! — Danilo Piazzalunga, Dec 20 '12 at 13:41
Just edit your question to remove the solution, and then paste it back as an answer. — Danilo Piazzalunga, Dec 20 '12 at 16:34

score 8 · Accepted Answer · answered Dec 20 '12 at 19:25

The solution was to create a visitor class that extends VoidVisitorAdapter and override the visit() method. Code follows:

@Override
public void visit(VariableDeclarationExpr n, Object arg)
{      
    List <VariableDeclarator> myVars = n.getVars();
        for (VariableDeclarator vars: myVars){
            System.out.println("Variable Name: "+vars.getId().getName());
            }
}

score 2 · Answer 2 · answered Jan 28 '14 at 19:44

Note that based on your solution, the original field listing can be done with the following code:

@Override
public void visit(FieldDeclaration n, Object arg) {
    System.out.println(n);
    super.visit(n, arg);
}

Don't forget to call super.visit, if you are overriding multiple visit methods in a visitor adapter.

score 1 · Answer 3 · edited Oct 24 '15 at 02:18

Working:

In the visit(FieldDeclaration n, Object arg) method of the VoidVisitorAdapter class, the following can be used for extracting variables.

It will give the exact name of the variables whether initialized or not.

String newstr;
List<VariableDeclarator> list = n.getVariables();
//as getVariables() returns a list we need to implement that way 
for (VariableDeclarator var : list) {

    String item = var.toString();

    if (item.contains("=")) {

        if (item != null && item.length() > 0) {

            int index = item.lastIndexOf("=");
            newstr = item.substring(0, index);
            newstr = newstr.trim();
            variablename = newstr;`
            //variablename is the name of the desired variable.
        }
    } 
}

Thanks @Pang for editing my answer. I'm new to this site and want to learn plus contribute. — Sangit Dhanani, Oct 30 '15 at 06:49

What is the correct way to parse variables using JavaParser?

3 Answers3