Package org.apache.cassandra.index.sasi.utils

Class RangeIntersectionIterator.LookupIntersectionIterator<K extends java.lang.Comparable<K>,​D extends CombinedValue<K>>

  • Type Parameters:
    K - The type used to sort ranges.
    D - The container type which is going to be returned by Iterator.next().
    All Implemented Interfaces:
    com.google.common.collect.PeekingIterator<D>, java.io.Closeable, java.lang.AutoCloseable, java.util.Iterator<D>
    Enclosing class:
    RangeIntersectionIterator
    protected static class RangeIntersectionIterator.LookupIntersectionIterator<K extends java.lang.Comparable<K>,​D extends CombinedValue<K>>
extends RangeIterator<K,​D>
    Iterator which performs a linear scan over a primary range (the smallest of the ranges) and O(log(n)) lookup into secondary ranges using values from the primary iterator. This technique is efficient when one of the intersection ranges is smaller than others e.g. ratio 0.01d (default), in such situation scan + lookup is more efficient comparing to "bounce" merge because "bounce" distance is never going to be big.

    • Method Detail

      • computeNext

        protected D computeNext()
        Description copied from class: AbstractIterator
        Returns the next element. Note: the implementation must call AbstractIterator.endOfData() when there are no elements left in the iteration. Failure to do so could result in an infinite loop.

        The initial invocation of AbstractIterator.hasNext() or AbstractIterator.next() calls this method, as does the first invocation of hasNext or next following each successful call to next. Once the implementation either invokes endOfData or throws an exception, computeNext is guaranteed to never be called again.

        If this method throws an exception, it will propagate outward to the hasNext or next invocation that invoked this method. Any further attempts to use the iterator will result in an IllegalStateException.

        The implementation of this method may not invoke the hasNext, next, or AbstractIterator.peek() methods on this instance; if it does, an IllegalStateException will result.

        Specified by:
        computeNext in class AbstractIterator<D extends CombinedValue<K>>
        Returns:
        the next element if there was one. If endOfData was called during execution, the return value will be ignored.