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POCan I strictly evaluate a boolean expression stored as a string in Java?
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copied!<p>I would like to be able to evaluate an boolean expression stored as a string, like the following:</p> <pre><code>"hello" == "goodbye" && 100 < 101 </code></pre> <p>I know that there are tons of questions like this on SO already, but I'm asking this one because I've tried the most common answer to this question, <a href="http://www.beanshell.org/" rel="nofollow noreferrer">BeanShell</a>, and it allows for the evaluation of statements like this one</p> <pre><code>"hello" == 100 </code></pre> <p>with no trouble at all. Does anyone know of a FOSS parser that throws errors for things like operand mismatch? Or is there a setting in BeanShell that will help me out? I've already tried Interpreter.setStrictJava(true).</p> <p>For completeness sake, here's the code that I'm using currently:</p> <pre><code>Interpreter interpreter = new Interpreter(); interpreter.setStrictJava(true); String testableCondition = "100 == \"hello\""; try { interpreter.eval("boolean result = ("+ testableCondition + ")"); System.out.println("result: "+interpreter.get("result")); if(interpreter.get("result") == null){ throw new ValidationFailure("Result was null"); } } catch (EvalError e) { e.printStackTrace(); throw new ValidationFailure("Eval error while parsing the condition"); } </code></pre> <p><strong>Edit:</strong></p> <p>The code I have currently returns this output</p> <pre><code>result: false </code></pre> <p>without error. What I would like it to do is throw an EvalError or <em>something</em> letting me know that there were mismatched operands.</p>

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