Package it.unimi.dsi.big.webgraph

Class NodeIterator

  • All Implemented Interfaces:
    it.unimi.dsi.fastutil.longs.LongIterator, java.util.Iterator<java.lang.Long>, java.util.PrimitiveIterator<java.lang.Long,​java.util.function.LongConsumer>, java.util.PrimitiveIterator.OfLong
    Direct Known Subclasses:
    ArcLabelledNodeIterator
    public abstract class NodeIterator
extends java.lang.Object
implements it.unimi.dsi.fastutil.longs.LongIterator
    This interface extends LongIterator and is used to scan a graph, that is, to read its nodes and their successor lists sequentially. The LongIterator.nextLong() method returns the node that will be scanned. After a call to this method, calling successors() or successorBigArray() will return the list of successors.

    Implementing subclasses can override either successors() or successorBigArray(), but at least one of them must be implemented.

    • Nested Class Summary

      • Nested classes/interfaces inherited from interface java.util.PrimitiveIterator

        java.util.PrimitiveIterator.OfDouble, java.util.PrimitiveIterator.OfInt, java.util.PrimitiveIterator.OfLong

    • Field Summary

      Fields 
      Modifier and Type Field Description
      static NodeIterator EMPTY
      An empty node iterator.

    • Constructor Summary

      Constructors 
      Constructor Description
      NodeIterator()  

    • Method Summary

      All Methods Instance Methods Abstract Methods Concrete Methods 
      Modifier and Type Method Description
      NodeIterator copy​(long upperBound)
      Creates a copy of this iterator that will never return nodes ≥ the specified bound; the copy must be accessible by a different thread.
      abstract long outdegree()
      Returns the outdegree of the current node.
      long skip​(long n)
      Skips the given number of elements.
      long[][] successorBigArray()
      Returns a reference to an array containing the successors of the current node.
      LazyLongIterator successors()
      Returns a lazy iterator over the successors of the current node.

      • Methods inherited from class java.lang.Object

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

      • Methods inherited from interface java.util.Iterator

        hasNext, remove

      • Methods inherited from interface it.unimi.dsi.fastutil.longs.LongIterator

        forEachRemaining, forEachRemaining, next, nextLong, skip

      • Methods inherited from interface java.util.PrimitiveIterator.OfLong

        forEachRemaining

    • Field Detail

      • EMPTY

        public static final NodeIterator EMPTY
        An empty node iterator.

    • Constructor Detail

      • NodeIterator

        public NodeIterator()

    • Method Detail

      • outdegree

        public abstract long outdegree()
        Returns the outdegree of the current node.
        Returns:
        the outdegree of the current node.

      • successors

        public LazyLongIterator successors()
        Returns a lazy iterator over the successors of the current node. The iteration terminates when -1 is returned.
        Returns:
        a lazy iterator over the successors of the current node.
        Implementation Specification:
        This implementation just wraps the array returned by successorBigArray().

      • successorBigArray

        public long[][] successorBigArray()
        Returns a reference to an array containing the successors of the current node.

        The returned array may contain more entries than the outdegree of the current node. However, only those with indices from 0 (inclusive) to the outdegree of the current node (exclusive) contain valid data.

        Returns:
        an array whose first elements are the successors of the current node; the array must not be modified by the caller.
        Implementation Specification:
        This implementation just unwrap the iterator returned by successors().

      • copy

        public NodeIterator copy​(long upperBound)
        Creates a copy of this iterator that will never return nodes ≥ the specified bound; the copy must be accessible by a different thread. Optional operation (it should be implemented by all classes that allow to scan the graph more than once).
        Parameters:
        upperBound - the upper bound.
        Returns:
        a copy of this iterator, with the given upper bound.
        Implementation Specification:
        This implementation just throws an UnsupportedOperationException. It should be kept in sync with the result of ImmutableGraph.hasCopiableIterators().

      • skip

        public long skip​(long n)
        Skips the given number of elements.

        The effect of this call is exactly the same as that of calling LongIterator.nextLong() for n times (possibly stopping if Iterator.hasNext() becomes false).

        This method is a big version of LongIterator.skip(int).

        Parameters:
        n - the number of elements to skip.
        Returns:
        the number of elements actually skipped.
        See Also:
        LongIterator.nextLong()