1. A computer program product, comprising: a non-transitory computer-readable storage medium having computer-readable program code embodied therewith, the computer-readable program code comprising: computer-readable program code configured to provide a plurality of processing elements comprising one or more operators, the operators configured to process streaming data tuples by operation of one or more computer processors; computer-readable program code configured to establish an operator graph of a plurality of operators, the operator graph defining at least one execution path in which a first operator of the plurality of operators is configured to: (i) receive data tuples from at least one upstream operator and (ii) transmit data tuples to at least one downstream operator; computer-readable program code configured to define a windowing condition specifying at least one rule for processing data tuples, wherein the at least one rule is based on one of: (i) a count of data tuples received by the first operator equaling a predefined count, (ii) expiration of a predefined period of time, and (iii) a change in an attribute value of the data tuples exceeding a predefined threshold; and computer-readable program code configured to, responsive to receiving, at a first operator of the plurality of operators, an indication to enforce the windowing condition on the first operator: process a first set of data tuples received by the first operator; and while processing the first set of data tuples, upon determining that the windowing condition has been satisfied: cease the processing of the first set of data tuples, wherein at least one data tuple of the first set of data tuples is not processed; and process a second set of data tuples.