36. The computer-readable volatile or non-volatile medium of claim 25 , wherein the instructions that cause the one or more processors to perform the step of said XML processor receiving said one or more requests for said particular information include instructions which, when executed by the one or more processors, cause the one or more processors to perform the step of receiving a request regarding a first annotation that is associated with said particular XML element of said XML-based input stream, wherein said first annotation is defined in information that dictates the structure of corresponding XML data.
37. The computer-readable volatile or non-volatile medium of claim 36 , wherein said information that dictates the structure of corresponding XML data comprises a second annotation definition that is associated with a second XML element of said XML-based input stream that is different than said particular XML element, wherein the instructions that cause the one or more processors to perform the step of said XML processor receiving said one or more requests for said particular information include instructions which, when executed by the one or more processors, cause the one or more processors to perform the step of receiving a request regarding said second annotation, and wherein the one or more sequences of instructions further comprise instructions which, when executed by the one or more processors, cause the one or more processors to perform the step of: before responding to said request regarding said second annotation, responding to a request regarding whether said particular XML element is defined in said information that dictates the structure of corresponding XML data.