Package io.deephaven.util

Class SoftRecyclerWindow

java.lang.Object
io.deephaven.util.SoftRecyclerWindow
public final class SoftRecyclerWindow extends Object
Decides when the windows of every registered SoftRecycler end, from the update cycles reported to it, so that no recycler reads a clock.

An update graph may report the start of each cycle through reportCycleStart(String, long); a graph that does not report has no say in the window. A window is long enough to span a whole cycle of each reporting graph: the largest of the graphs' latest intervals between cycle starts, times "SoftRecycler.windowMargin" (1.5 by default) for jitter, but no shorter than "SoftRecycler.windowMillis"<T> milliseconds (1000 by default) and no longer than "SoftRecycler.maximumWindowMillis" milliseconds (60000 by default). Each graph contributes only its latest interval, so a graph that slowed for a cycle stops lengthening the window at its next cycle, and a graph that has not started a cycle within the longest window, because it is idle or gone, is ignored. An interval longer than the longest window, as an event-driven graph's idle time might be, counts as the longest window.

Each report also ends the current window if it has lasted long enough, so a window ends at the first cycle start, of any reporting graph, after it has elapsed. A process in which no graph reports never ends a window, so its recyclers never shrink, and the garbage collector reclaims their items under memory pressure as it always may.

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final String
    MAXIMUM_WINDOW_MILLIS_PROPERTY
    The property for the longest window, in milliseconds, between possibly shrinking the recyclers.
    static final String
    WINDOW_MARGIN_PROPERTY
    The property for the multiple of the longest interval between cycle starts that a window lasts.

  • Method Summary

    Modifier and Type
    Method
    Description
    static void
    forgetGraph(@NotNull String graphName)
    Stop counting a graph's cycles toward the window, as when the graph is removed.
    static <T> SoftRecycler<T>
    register(@NotNull SoftRecycler<T> recycler)
    Register recycler, so that its window ends with every other registered recycler's, from the update graphs' cycles.
    static void
    reportCycleStart(@NotNull String graphName, long startNanos)
    Report that an update graph started a cycle, and end every recycler's window if it has lasted long enough.

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Field Details

    • MAXIMUM_WINDOW_MILLIS_PROPERTY

      public static final String MAXIMUM_WINDOW_MILLIS_PROPERTY
      The property for the longest window, in milliseconds, between possibly shrinking the recyclers. Even if one of the reporting graphs has a longer interval between cycles, the next reporting graph to start a cycle ends the window, possibly shrinking the recyclers, once the window exceeds this value.
      See Also:

    • WINDOW_MARGIN_PROPERTY

      public static final String WINDOW_MARGIN_PROPERTY
      The property for the multiple of the longest interval between cycle starts that a window lasts.
      See Also:

  • Method Details

    • register

      public static <T> SoftRecycler<T> register(@NotNull @NotNull SoftRecycler<T> recycler)
      Register recycler, so that its window ends with every other registered recycler's, from the update graphs' cycles. Registered recyclers are held strongly and never unregistered, so register only a recycler that lives for the life of the process, as the column sources' static ones do. A recycler that is not registered never shrinks.
      Parameters:
      recycler - The recycler to register
      Returns:
      recycler, for the convenience of the caller

    • reportCycleStart

      public static void reportCycleStart(@NotNull @NotNull String graphName, long startNanos)
      Report that an update graph started a cycle, and end every recycler's window if it has lasted long enough. Called by the graph's update thread, with a time the graph has already read.
      Parameters:
      graphName - the name of the graph
      startNanos - when the cycle started, from System.nanoTime()

    • forgetGraph

      public static void forgetGraph(@NotNull @NotNull String graphName)
      Stop counting a graph's cycles toward the window, as when the graph is removed.
      Parameters:
      graphName - the name of the graph