Recently I’ve been playing with some old Java Swing applications and I found myself wishing that I could replace all the anonymous inner-classes with some clean Groovy closures. The job of converting a java source file to a groovy source file is pretty simple and eminently scriptable. Here’s my take on a python script to do just that:

from optparse import OptionParser
from subprocess import Popen, PIPE
import os

def rename(src, dest, use_svn):
    if use_svn:
        output = Popen(['svn', 'rename', src, dest], stdout=PIPE).communicate()
        print output[0]
    else:
        print 'mv', src, dest
        os.rename(src, dest)

def process_file(src, use_svn):
    if src.endswith('.java'):
        print 'Processing', src
        fd = open(src, 'r')
        lines = fd.readlines()
        fd.close()
        fd = open(src, 'w')
        for line in lines:
            text = line.rstrip()
            if text.endswith(';'):
                text = text[:-1]
            fd.write(text)
            fd.write('\n')
        fd.close()
        root = os.path.dirname(src)
        filename = os.path.basename(src)
        dest = os.path.join(root, filename[:-5] + '.groovy')
        rename(src, dest, use_svn)

def process_dir(dir_path, use_svn):
    for root, dirs, files in os.walk(dir_path):
        for filename in files:
            src = os.path.join(root, filename)
            process_file(src, use_svn)

if __name__ == '__main__':
    parser = OptionParser()
    parser.add_option('-s', '--svn', action='store_true', dest='use_svn', help='use svn to rename files')
    (options, args) = parser.parse_args()
    if len(args) > 0:
        target = args[0]
        if os.path.isfile(target):
            process_file(target, options.use_svn)
        else:
            process_dir(target, options.use_svn)
    else:
        process_dir(os.getcwd(), options.use_svn)

This means that I can now replace this:

public void actionPerformed(ActionEvent e) {
    executor.execute(new Runnable() {
        public void run() {
            controller.showBuckets();
        }
    });
}

with this:

public void actionPerformed(ActionEvent e) {
    executor.execute { controller.showBuckets() }
}

Now that’s refactoring

Tags: Closure, groovy, Java, Python, swing