Package org.roaringbitmap.buffer

Class RoaringBatchIterator

  • All Implemented Interfaces:
    java.lang.Cloneable, BatchIterator
    public final class RoaringBatchIterator
extends java.lang.Object
implements BatchIterator

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void advanceIfNeeded​(int target)
      If needed, advance as long as the next value is smaller than minval The advanceIfNeeded method is used for performance reasons, to skip over unnecessary repeated calls to next.
      BatchIterator clone()
      Creates a copy of the iterator.
      boolean hasNext()
      Returns true is there are more values to get.
      int nextBatch​(int[] buffer)
      Writes the next batch of integers onto the buffer, and returns how many were written.

      • Methods inherited from class java.lang.Object

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

    • Method Detail

      • nextBatch

        public int nextBatch​(int[] buffer)
        Description copied from interface: BatchIterator
        Writes the next batch of integers onto the buffer, and returns how many were written. Aims to fill the buffer.
        Specified by:
        nextBatch in interface BatchIterator
        Parameters:
        buffer - - the target to write onto
        Returns:
        how many values were written during the call.

      • hasNext

        public boolean hasNext()
        Description copied from interface: BatchIterator
        Returns true is there are more values to get.
        Specified by:
        hasNext in interface BatchIterator
        Returns:
        whether the iterator is exhaused or not.

      • advanceIfNeeded

        public void advanceIfNeeded​(int target)
        Description copied from interface: BatchIterator
        If needed, advance as long as the next value is smaller than minval The advanceIfNeeded method is used for performance reasons, to skip over unnecessary repeated calls to next. Suppose for example that you wish to compute the intersection between an ordered list of integers (e.g., int[] x = {1,4,5}) and a BatchIterator. You might do it as follows... 
        
     int[] buffer = new int[128];
     BatchIterator j = // get an iterator
     int val = // first value from my other data structure
     j.advanceIfNeeded(val);
     while ( j.hasNext() ) {
       int limit = j.nextBatch(buffer);
       for (int i = 0; i < limit; i++) {
         if (buffer[i] == val) {
           // got it!
           // do something here
           val = // get next value?
         }
       }
       j.advanceIfNeeded(val);
     }
        The benefit of calling advanceIfNeeded is that each such call can be much faster than repeated calls to "next". The underlying implementation can "skip" over some data.
        Specified by:
        advanceIfNeeded in interface BatchIterator
        Parameters:
        target - threshold

      • clone

        public BatchIterator clone()
        Description copied from interface: BatchIterator
        Creates a copy of the iterator.
        Specified by:
        clone in interface BatchIterator
        Overrides:
        clone in class java.lang.Object
        Returns:
        a clone of the current iterator