added more readme stuff
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README.md
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README.md
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@ -151,3 +151,81 @@ When the debug mode flag has been set to _true_, you can use the <a href="http:/
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After pressing "GO", the tests will run and you can inspect stuff and step through the code.
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After pressing "GO", the tests will run and you can inspect stuff and step through the code.
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Integrated debugging into for example Eclipse does not work for the moment.
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Integrated debugging into for example Eclipse does not work for the moment.
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* * *
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# Advanced: Implementation details
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## RhinoContext API
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The _RhinoContext_ class is basically a wrapper/facade/whatever which allows you to easily manipulate the Javascript scope.
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Read <a href="https://developer.mozilla.org/En/Rhino_documentation/Scopes_and_Contexts" target="_blank">Rhino docs: scopes and contexts</a> first please!
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Creating a new RhinoContext initializes one "root" scope (toplevel), and assignes one context to the current Thread.
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### Evaluating async javascript code
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Creating another RhinoContext while passing the root scope, uses prototypal inheritance to create a new toplevel scope. This means the root scope is shared across different contexts (and thus different threads).
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You can execute the _runAsync_ method, which does this:
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* create a new thread and thus a new context
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* create a new scope based on the root one -> shared
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* execute stuff in the new scope (You can access root JS functions but not modify them, remember prototypal inheritance!)
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* cleanup
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For example, JasmineSpec uses the _execute_ Jasmine JS function on a spec and calls it in another thread:
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```java
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baseContext.runAsync(new RhinoRunnable() {
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@Override
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public void run(RhinoContext context) {
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// get some random spec from Jasmine
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NativeObject someSpec = (NativeObject) context.evalJS("jasmine.getEnv().currentRunner().suites()[0].specs()[0]");
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context.executeFunction(someSpec, "execute");
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}
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});
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``
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### Creating a Rhino debugger
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Basically creates a _org.mozilla.javascript.tools.debugger.Main_ object. Pitfall: create before loading all required JS files, but after creating the rhino context!
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To acutally break once (so users can set breakpoints and press GO), use this:
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> debugger.doBreak();
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### Executing functions
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_executeFunction_ is a convenience method to call a function on a passed NativeObject. The function pointer may reside in the object's prototype, you don't need to explicitly check this in Javascript but you do using Rhino!
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## Envjs Utils/Hacks
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### Error.stack fix
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In firefox, you can get a stacktrace from a JS exception using:
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> new Error("BOOM").stack
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Of course this does not work in Envjs. But Rhino attaches an internal _rhinoException_ to each JS Error object, so using a bit of magic, now it's possible to call _getStackTrace()_
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### Envjs.uri Windows relative paths fix
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Use _file:///_ (three forward slashes) if no context has been provided. Works like this:
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```javascript
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Envjs.uri(path, "file:///" + ("" + Envjs.getcwd()).replace(/\\/g, '/') + "/")
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```
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### window.setTimeout fix
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Used by Jasmine internally for async spec execution, but for some reason the Envjs Javascript implementation is broken.
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A simple fix is possible, since using Rhino you can call Java objects in Javascript space! Wow awesome. So just create a new thread and use _sleep_:
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```javascript
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window.setTimeout = function(closure, timeout) {
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spawn(function() {
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java.lang.Thread.sleep(timeout);
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closure();
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});
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};
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```
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