Multiple Assertions

You can nest multiple assertions in receive activities, invoke activities, and the onMessage branch of pick and scope activities, with evaluation of the assertions continuing in the order in which they were declared until an expression evaluates to false. The following example provides details:

<invoke name="invokeCR" partnerLink="creditRatingService"
        portType="services:CreditRatingService" operation="process"
        inputVariable="crInput" outputVariable="crOutput">
    <bpelx:postAssert name="negativeCredit" expression="$crOutput.payload/tns:rating >
 0"
                  faultName="services:NegativeCredit" message="'Negative Credit'"
 />
    <bpelx:postAssert name="insufficientCredit"
 expression="$crOutput.payload/tns:rating > 600"
                  faultName="services:InsufficientCredit" message="'Insufficient
 Credit'" />
</invoke>

In the preceding example, the assertion with the expression that checks that the response credit rating is greater than zero is evaluated first. Table 12-11 describes the assertion behavior.

Table 12-11 Assertion Behavior

If The Credit Rating For The Returned Response Is...	Then...
Less than zero	The `services:NegativeCredit` fault is thrown.
Greater than or equal to zero	The assertion is correct and the second assertion is evaluated.
Less than 600	The `services:InsufficientCredit` fault is thrown.
Greater than or equal to 600	The assertion is correct and no fault is thrown from the invoke activity.

Any number of assertions can be nested. For no fault to be thrown from the activity, all assertions specified must evaluate to true.

This construct enables you to apply multiple levels of validation on an incoming payload, similar to if...else if...else statements in Java.

To enable a fault to always be thrown regardless of validation logic, the assertion expression can be specified as false(). This is similar to the else construct in Java.