1. A system for processing a stream of tuples comprising: a plurality of processing elements to receive a stream of tuples, each processing element including one or more stream operators, wherein one or more of the stream operators include code configured to output tuples to one or more other stream operators; two or more processors; and a memory containing an application that, when executed, causes at least one of the two or more processors to: generate a window over at least one stream operator, the window being defined by a set of windowing conditions, the set of windowing conditions including a set of breakpoint thresholds and a reset policy, the set of breakpoint thresholds including a first breakpoint threshold, wherein the reset policy is a time interval, wherein the first breakpoint threshold sets a maximum number of tuples that are permitted to enter the window during a windowing period; determine a set of tuple flow counts for the window, the set of tuple flow counts corresponding to the set of breakpoint thresholds, the set of tuple flow counts including a first tuple flow count, wherein the first tuple flow count is a number of tuples that have entered the window during the windowing period; determine that a breakpoint condition has occurred by comparing the set of tuple flow counts to the set of breakpoint thresholds, wherein determining that the breakpoint condition has occurred includes determining that the number of tuples that has entered the window during the windowing period exceeds the maximum number of tuples; and implement, in response to determining that the breakpoint condition has occurred, a tuple flow change; determine that the reset policy has triggered by determining that an amount of time since generating the window exceeds the time interval; and reset, in response to determining that the reset policy has triggered, the set of tuple flow counts for the window.