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copied!<p>This question was asked ages ago, but the answers still seemed correct. In case it's of interest to anyone else trying to pass complex objects between Java and Javascript, I wanted to present my solution.</p> <p>I wrote a script that converts the NativeObject to (in-memory) JSON objects (actually I use MongoDB's BSON-based objects, but you should just be able to substitute 1-1 for JSONArray and JSONObject in the sample code below).</p> <p>So for example, say I have a (user) script "create_object_script", which "returns" some object or array of interest, then I can convert it into JSON (ie a list of hashmaps) as follows:</p> <pre><code>Object returnVal = engine.eval(create_object_script); engine.put("output", returnVal); BasicDBObject objFactory = new BasicDBObject(); // (or JSON equivalent) BasicDBList listFactory = new BasicDBList(); // (or JSON equivalent) BasicDBList outList = new BasicDBList(); // (or JSON equivalent) engine.put("objFactory", objFactory); engine.put("listFactory", listFactory); engine.put("outList", outList); engine.eval(parsing_script); // (described below) // "outList" is now populated with (in-memory) JSON representations of "returnVal" </code></pre> <p>Obviously if you have control over the "create_object_script" script you can do this in a single step; my scripts are user-generated so hiding away this complexity is necessary - the users just write scripts where the "return value" is the final line.</p> <p>I gisted the "parsing_script" <a href="https://gist.github.com/1571455" rel="nofollow" title="here">here</a> to keep the length of this post down.</p> <p>Functionally this works very nicely; I haven't developed in JS much so it's possible there are more efficient ways of doing this. (Note I always need my results in a list, if you don't then you could pass in a BasicDBObject "outObj" and write to that instead in the singleton case).</p> <p>Hope this helps someone who finds themselves in my situation at 1am last night!</p>

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