Evaluate the GROOVY expression in Oracle SQL/PLSQL - oracle

Question

I have one Groovy expression. (stored in master table but let's consider it as an individual string for this question)
Example of Groovy expression: if(shortName.equals("do not include")){return false;}; return true;
I want to use it in my oracle SQL query to consider this groovy expression to filter the records. Please note that the shortName is the column of the database table.
I want something like this:
SELECT * FROM MYTABLE
WHERE SOME_FFUNCTION_TO_EVALUATE_GROOVY(<GROOVY_EXPRESSION>);
Thanks in advance.

Answer 1

Perhaps easiest way to do is using javax.script.ScriptEngine and javax.script.ScriptEngineManager classes.
Step 1 : Download the jar files from maven repository for latest stable version of groovy libraries.
https://repo1.maven.org/maven2/org/codehaus/groovy/groovy-all/2.5.10/groovy-all-2.5.10-sources.jar
Step 2 : Load the jar file to schema using loadjava utility. Post import check data dictionary to ensure the java source is loaded to the database to appropriate schema. https://docs.oracle.com/cd/A87860_01/doc/java.817/a81358/02_load3.htm
Step 3: Create java source with a method for groovy expression evaluation.The method accepts string as input and returns 1 if expression evaluates to true and 0 when evaluated to false.This method creates instance of ScriptEngine and calls eval method to evaluate the input expression.
create or replace and resolve java source named
"GroovyEval" as
import java.math.*;
import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
import javax.script.ScriptException;
/**
* Java class to Evaluate Groovy String
*/
public class GroovyEval {
/**
* #param String
* #return 1 if True else 0 if False
*/
public static int evalGroovyExpr(String expr) throws ScriptException{
ScriptEngineManager factory = new ScriptEngineManager();
ScriptEngine engine = factory.getEngineByName("groovy");
Object result = engine.eval(expr);
int lv_output = 0;
if (result.toString().equals("true"))
{
lv_output = 1;
}
if (result.toString().equals("false"))
{
lv_output = 0;
}
return lv_output;
}
};
/
Step 4 : Create a Stored function to call the java source.
create or replace function evaluateGroovyExpr
(n number)
return number
as language java
name 'GroovyEval.evaluateGroovyExpr(String) return int';
/
Step 5: Fire the SQL query to call the function.You might use table columns to build groovy expression, but this is just a demo.
with exprtab as
(select '''do not include''.equals(''do not include'')' expr from dual)
SELECT evaluateGroovyExpr(expr) from exprtab;
Result
1
PS :
Using single quotes to frame the expression will be ideal as that wouldn't confuse JVM.
This is not one solution for all, but works for all expression that evaluates to boolean.
Tips: Idea approach to develop/debug would be to create the class in java and evaluate your expressions and then integrate it to the database.

Answer 2

You can use Eval function in groovy library of java using java stored procedure in DB
A simple example of Eval is given here
The documentation of Eval is given here
If you want to know how to use java stored procedure in oracle DB an example is given here
Also You have to use loadjava to load the groovy library in oracle DB