Boolean b1 = true;
Boolean b2 = true;
String b3 = 'b1 && b2';
Boolean b4 = Boolean.valueOf(b3);
system.debug('test Bool '+ b4);
Given a string how can you convert into expression without breaking the sting.
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I'm curious how you want to apply this, or what problem you need to solve?– pchittumCommented Jan 29, 2013 at 12:20
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In the above example I will get raw data as as show in b3 and need to evaluate true or false.– Ugesh GaliCommented Jan 29, 2013 at 12:22
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Would it help if you convert your conditions into a dynamic query and act on results from that?– LVSCommented May 3, 2013 at 11:13
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4 Answers
It is possible to mimic a Javascript eval() in Apex by making a callout to the executeAnonymous API method.
There are two common ways you can get a response back from executeAnonymous.
- Throw a deliberate exception at the end of the execute and include the response. Kevin covers this approach in EVAL() in Apex. Secure Dynamic Code Evaluation on the Salesforce1 Platform.
- I used a variation of this approach but returned the response via the debug log rather than an intentional exception. See Adding Eval() support to Apex.
Using my example the Apex would be something like:
string toEval =
'Boolean b1 = true;' +
'Boolean b2 = true;' +
'boolean b3 = b1 && b2;' +
'System.debug(LoggingLevel.Error, b3);';
boolean b4 = soapSforceCom200608Apex.evalBoolean( toEval );
system.debug('test Bool '+ b4);
answered Nov 28, 2014 at 1:12
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You rock! Never known this is possible in Apex!!!! You have my vote up!– PatlatusCommented Apr 16, 2015 at 8:55
I think what you're after doing is creating an expression as a string and then evaluating it and obtaining the result in Apex.
I don't think it is actually possible to evaluate expressions in Apex natively (it would be great if it was, I also wondered the same since we have the Formula functions). I think the best you could do is roll your own expression parser and AND(Boolean, Boolean) function that implements the required behaviour.
answered Jan 29, 2013 at 12:14
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Thank you. Will think of building own expression parser. Commented Jan 29, 2013 at 12:17
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No. There are some native features that will evaluate your string such as Database.insert and other DML methods. But not an arbitrary expression.– pchittumCommented Jan 29, 2013 at 12:19
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I want do it in apex and expression is much more complex. Commented Jan 29, 2013 at 12:20
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2You should probably research the Interpreter design pattern, one thing to obviously be wary of from the start when going down this route would be the limits around script statements, especially if you're going to try and implement complex/recursive expressions. I'd be interested to hear if anyone else has any clever tricks in this area. Commented Jan 29, 2013 at 12:23
I created an apex class on github to do this. Take a look at this... https://github.com/hsaraujo/BooleanEvaluate-Apex
List<Boolean> values = new List<Boolean>{
true, false, true, true, false, true, true, true
};
BooleanEvaluate boolEval = new BooleanEvaluate('1 && ( ( 2 || 3 ) && 6 ) && ( 4 && 5 || ( 7 && 8 ) )', values);
boolEval.evaluate();
If someone wants to improve it, please fork! Hope it helps
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1please include the essentials of the link in your post, as is, this is a link only answer, although it might help, if the link becomes invalid, so will your answer. Please update accordingly and take some time to review How to Answer and take the tour. thanks!– gllsCommented Oct 27, 2017 at 2:08
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Hi @glls, This is my first answer here, thank you for your tips Commented Nov 6, 2017 at 2:12
Also you can try Script.apex(https://github.com/Click-to-Cloud/Script.apex)
Map context = new Map{ b1 => true, b2 => false };
Boolean result = (Boolean)ScriptEngine.getInstance().eval('b1 && b2', context);
