Class AllocationCache


  • class AllocationCache
    extends java.lang.Object
    An auxiliary object to cache the allocation information for a file container. Only a FileContainer should use this object

    The allocation cache contains an array of AllocExtents and 3 arrays of longs:

    1. ExtentPageNums[i] is the page number of the i'th extent
    2. lowRange[i] is the smallest page number managed by extent i
    3. hiRange[i] is the largest page number managed by extent i

    Note thate extentPageNums and lowRange does not change once the extent has been created, but hiRange will change for the last extent as more pages are allocated.

    Extents can be individually invalidated or the entire cache (all extends) can be invalidated at once.

    MT - unsafe Synrhonized access to all methods must be enforced by the caller of AllocationCache