Hi Radhika,
The validate policy is for validating the body only, not parameters. The only parameter validation that is done today is the required property. For now my only suggestion would be to have a GatewayScript policy at the beginning of the assembly that would do a context.reject if the value doesn't match what you want. You could open a PMR to have this done based upon the parameter configuration, but my assumption would be this would be considered a request for enhancement although I would see this as a useful feature.
Best Regards,
Steve
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Steve Linn
Senior Consulting I/T Specialist
IBM
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