Package net.sf.saxon.tree.iter

Class UntypedAtomizingIterator

  • All Implemented Interfaces:
    java.io.Closeable, java.lang.AutoCloseable, LastPositionFinder, SequenceIterator, LookaheadIterator
    public class UntypedAtomizingIterator
extends java.lang.Object
implements SequenceIterator, LastPositionFinder, LookaheadIterator
    AtomizingIterator returns the atomization of an underlying sequence supplied as an iterator. We use a specialist class rather than a general-purpose MappingIterator for performance, especially as the relationship of items in the result sequence to those in the base sequence is often one-to-one.

    This UntypedAtomizingIterator is used only when it is known that the input sequence consists entirely of nodes, and that all nodes will be untyped.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void close()
      Close the iterator.
      void discharge()
      Calling this method instructs the iterator to release any resources it holds, while still remaining able to deliver the remaining items in the sequence.
      int getLength()
      Get the last position (that is, the number of items in the sequence).
      boolean hasNext()
      Determine whether there are more items to come.
      AtomicValue next()
      Get the next item in the sequence.
      boolean supportsGetLength()
      Ask whether this iterator supports use of the getLength() method.
      boolean supportsHasNext()
      Ask whether the hasNext() method can be called.

      • Methods inherited from class java.lang.Object

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

    • Constructor Detail

      • UntypedAtomizingIterator

        public UntypedAtomizingIterator​(SequenceIterator base)
        Construct an AtomizingIterator that will atomize the values returned by the base iterator.
        Parameters:
        base - the base iterator

    • Method Detail

      • next

        public AtomicValue next()
        Description copied from interface: SequenceIterator
        Get the next item in the sequence. This method changes the state of the iterator.
        Specified by:
        next in interface SequenceIterator
        Returns:
        the next item, or null if there are no more items. Once a call on next() has returned null, no further calls should be made. The preferred action for an iterator if subsequent calls on next() are made is to return null again, and all implementations within Saxon follow this rule.

      • close

        public void close()
        Description copied from interface: SequenceIterator
        Close the iterator. This indicates to the supplier of the data that the client does not require any more items to be delivered by the iterator. This may enable the supplier to release resources. After calling close(), no further calls on the iterator should be made; if further calls are made, the effect of such calls is undefined.

        For example, the iterator returned by the unparsed-text-lines() function has a close() method that causes the underlying input stream to be closed, whether or not the file has been read to completion.

        Closing an iterator is important when the data is being "pushed" in another thread. Closing the iterator terminates that thread and means that it needs to do no additional work. Indeed, failing to close the iterator may cause the push thread to hang waiting for the buffer to be emptied.

        Closing an iterator is not necessary if the iterator is read to completion: if a call on SequenceIterator.next() returns null, the iterator will be closed automatically. An explicit call on SequenceIterator.close() is needed only when iteration is abandoned prematurely.

        Specified by:
        close in interface java.lang.AutoCloseable
        Specified by:
        close in interface java.io.Closeable
        Specified by:
        close in interface SequenceIterator

      • discharge

        public void discharge()
        Description copied from interface: SequenceIterator
        Calling this method instructs the iterator to release any resources it holds, while still remaining able to deliver the remaining items in the sequence. This may require the iterator to calculate the rest of the sequence eagerly. The method is called by a client if it anticipates that it might not read the iterator to completion, but it cannot guarantee that SequenceIterator.close() will be called when no more items are needed.
        Specified by:
        discharge in interface SequenceIterator

      • supportsGetLength

        public boolean supportsGetLength()
        Ask whether this iterator supports use of the getLength() method. This method should always be called before calling getLength(), because an iterator that implements this interface may support use of getLength() in some situations and not in others
        Specified by:
        supportsGetLength in interface LastPositionFinder
        Returns:
        true if the getLength() method can be called to determine the length of the underlying sequence.

      • getLength

        public int getLength()
        Description copied from interface: LastPositionFinder
        Get the last position (that is, the number of items in the sequence). This method is non-destructive: it does not change the state of the iterator. The result is undefined if the next() method of the iterator has already returned null. This method must not be called unless the LastPositionFinder.supportsGetLength() has been called and has returned true.
        Specified by:
        getLength in interface LastPositionFinder
        Returns:
        the number of items in the sequence

      • supportsHasNext

        public boolean supportsHasNext()
        Description copied from interface: LookaheadIterator
        Ask whether the hasNext() method can be called. This method must be called before calling hasNext(), because some iterators implement this interface, but only support look-ahead under particular circumstances (this is usually because they delegate to another iterator)
        Specified by:
        supportsHasNext in interface LookaheadIterator
        Returns:
        true if the LookaheadIterator.hasNext() method is available

      • hasNext

        public boolean hasNext()
        Description copied from interface: LookaheadIterator
        Determine whether there are more items to come. Note that this operation is stateless and it is not necessary (or usual) to call it before calling next(). It is used only when there is an explicit need to tell if we are at the last element.

        This method must not be called unless the result of LookaheadIterator.supportsHasNext() is true.

        Specified by:
        hasNext in interface LookaheadIterator
        Returns:
        true if there are more items in the sequence