multiDeclRefactor

Simple and a bit ugly tool for refactoring multiple declarations in Java:

For example, given a Java file with multiple variables declared in a single statement::

public class MultiDecl {
    private int a, b, c;

    public List<String> d = new ArrayList<>(),
                        e,
                        f;
}

it will refactor the code so that each statement declares just one variable:

public class MultiDecl {
private int a;
private int b;
private int c;

public List<String> d = new ArrayList<>();
public List<String> e;
public List<String> f;
}

This tool is intended to be used as a pre-processor before running a code analysis tool. The refactored code is not very human-readable:

1. It removes all comments on a multi-variable declaration statement.

2. It does not retain the original indentation.

building

To build the tool, run:

./fetch_dependency.sh

usage

./run-refactor.sh a.java b.java ...

dependency

This tool depends on a hacked version of checkstyle in my git repo. (branch multiDeclJson)

The hacked version of checkstyle is the backend of this tool, i.e. it detects the multiple declarations in a source file and then propagates the diagnostic result to this tool.

I currently still not have time to write test framework for this tool, but hopefully I will create one soon.

developer notes

Architecture

This tool is actually just a light-weight front-end that receives diagnostic reports and then do refactors based on the reports, i.e. it doesn't has the ability of detecting multi-declaration issues, instead, it needs a back-end reports issues and then it do refactors based on reports.

It uses json as the data format, and the diagnostic report format shown below:

[
        {"file" : absolute_java_file_path,
         "line" : line_number,
         "declared_type" : type
        },
        {"file" : absolute_java_file_path,
         "line" : line_number,
         "declared_type" : type
        }
]

In above json format, "file" is the absolute java file path that contains one or more multi-declaration issues. "line" is the start line number of a multi-declaration issue. "declared_type" is the java type with modifiers for a multi-declarations.

I currently have a controller_checkstyle.py as the middleware between the checkstyle backend and multiDeclRefactor frontend.

Current architecture would make below future changes easy:

• provides a new frontend/backend: just make a frontend/backend whose output follows the json protocol.

• extend the refactor to process a new kind of issue: make hacks on checkstyle, provides a **check.xml to do the issue check, and then add a new python front-end to do the refactor.