samples/find_nonfinals.js

/*
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 *
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 *     from this software without specific prior written permission.
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
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/**
 * Nashorn project uses "final" modifier for method parameters
 * (like 'val' of Scala). This tool finds method parameters that
 * miss final modifier.
 */

// Usage: jjs -J-Djava.ext.dirs=<your_nashorn_jar_dir> find_nonfinals.js

var Class = Java.type("java.lang.Class");
var System = Java.type("java.lang.System");
var Thread = Java.type("java.lang.Thread");
var File = Java.type("java.io.File");
var JarFile = Java.type("java.util.jar.JarFile");
var Modifier = Java.type("java.lang.reflect.Modifier");

// locate nashorn.jar from java.ext.dirs
function findNashorn() {
    var paths = System.getProperty("java.ext.dirs").split(File.pathSeparator);
    for each (var p in paths) {
        var nashorn = p + File.separator + "nashorn.jar";
        if (new File(nashorn).exists()) {
            return nashorn;
        }
    }
}

// analyze a single Class and print info on non-final parameters
function analyzeClass(cls) {
    var methods = cls.getDeclaredMethods();
    for each (var method in methods) {
        var methodModifiers = method.modifiers;
        if (Modifier.isAbstract(methodModifiers) || Modifier.isNative(methodModifiers)) {
            continue;
        }
        // this requires -parameters option when compiling java sources
        var params = method.parameters;
        for each (var p in params) {
           var modifiers = p.modifiers;
           if (!Modifier.isFinal(modifiers)) {
               if (! method.name.startsWith("access$")) {
                   print(method);
                   print(" ->", p);
               }
           }
        }
    }
}

var jarFile = findNashorn();
var ctxtLoader = Thread.currentThread().contextClassLoader;

// load each class and use reflection to analyze each Class
new JarFile(jarFile).stream().forEach(
    function(entry) {
        var name = entry.name;
        if (name.endsWith(".class")) {
            var clsName = name.substring(0, name.lastIndexOf('.class'));
            clsName = clsName.replace(/\//g, '.');
            try {
                // don't initialize to avoid for possible initialization errors 
                var cls = Class.forName(clsName, false, ctxtLoader);
                analyzeClass(cls);
            } catch (e) {
                // print exception and continue analysis for other classes
                print("Failed to analyze " + clsName);
                e.printStackTrace();
            }
        }
    }
)