You can specify a timeout setting as an absolute deadline for request-response receive activities. For BPEL 2.0, the syntax is as shown in the following example:

<receive <bpelx:until>"deadline-expr"</bpelx:until>
</receive>

For BPEL 1.1, the syntax is as shown in the following example:

<receive bpelx:until="deadline-expr">
    standard-elements
</receive>

The expected expiration time for the bpelx:until attribute must be at least two seconds ahead of the current time. Otherwise, the timer scheduling is ignored and skipped, just as if the timer was never specified.

The bpelx:until attribute specifies a static value or an XPath expression that must evaluate to an XML schema type datetime or date. Only one of the bpelx:for or bpelx:until attributes is permitted for an activity.

XPath version 1.0 is not XML schema-aware. Therefore, none of the built-in functions of XPath version 1.0 can create or manipulate dateTime or date values. However, it is possible to perform one of the following:

• Write a constant (literal) that conforms to XML schema definitions and use that as a deadline value.

• Extract a field from a variable (part) of one of these types and use that as a deadline value.

XPath version 1.0 treats that literal as a string literal, but the result can be interpreted as a lexical representation of a dateTime or date value.

Once a valid datetime or date value has been retrieved, the expiration date for the activity is set to the specified date. For example, the datetime value bpelx:until="'2009-12-24T18:00+01:00'" specifies that the activity expects an inbound message to arrive no later than Dec 24, 2009 6:00 pm UTC+1 after the activity has started execution.

Timeout dates can only be specified on the following activities:

• Midprocess receives

• Receive activities that do not specify createInstance="true"

A receive activity can only time out after it has been instantiated, which is not the case with entry receive activities.