Package it.unimi.dsi.webgraph

Class NodeIterator

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

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

    The copy(int) methods is in fact optional, but should be implemented whenever the graph can be scanned more than once.

    • 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​(int 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 int outdegree()
      Returns the outdegree of the current node.
      int[] successorArray()
      Returns a reference to an array containing the successors of the current node.
      LazyIntIterator 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 it.unimi.dsi.fastutil.ints.IntIterator

        forEachRemaining, forEachRemaining, next, nextInt, skip

      • Methods inherited from interface java.util.Iterator

        hasNext, remove

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

        forEachRemaining

    • Field Detail

      • EMPTY

        public static final NodeIterator EMPTY
        An empty node iterator.

    • Constructor Detail

      • NodeIterator

        public NodeIterator()

    • Method Detail

      • outdegree

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

      • successors

        public LazyIntIterator successors()
        Returns a lazy iterator over the successors of the current node. The iteration terminates when -1 is returned.

        This implementation just wraps the array returned by successorArray().

        Returns:
        a lazy iterator over the successors of the current node.

      • successorArray

        public int[] successorArray()
        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​(int 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().