Package net.sf.saxon.expr

Class EveryItemMappingIterator

java.lang.Object
net.sf.saxon.expr.EveryItemMappingIterator
All Implemented Interfaces:
Closeable, AutoCloseable, SequenceIterator
public final class EveryItemMappingIterator extends Object implements SequenceIterator
EveryItemMappingIterator applies a mapping function to each item in a sequence. The mapping function always returns a single item (never null)

This is a specialization of the more general MappingIterator class, for use in cases where a single input item always maps to exactly one output item

  • Constructor Details

    • EveryItemMappingIterator

      public EveryItemMappingIterator(SequenceIterator base, ItemMappingFunction action)
      Construct an ItemMappingIterator that will apply a specified DummyItemMappingFunction to each Item returned by the base iterator.
      Parameters:
      base - the base iterator
      action - the mapping function to be applied

  • Method Details

    • next

      public Item next() throws XPathException
      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.
      Throws:
      XPathException - if an error occurs retrieving the next item

    • 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.

      Specified by:
      close in interface AutoCloseable
      Specified by:
      close in interface Closeable
      Specified by:
      close in interface SequenceIterator

    • getProperties

      public int getProperties()
      Get properties of this iterator, as a bit-significant integer.
      Specified by:
      getProperties in interface SequenceIterator
      Returns:
      the properties of this iterator. This will be some combination of properties such as SequenceIterator.GROUNDED, SequenceIterator.LAST_POSITION_FINDER, and SequenceIterator.LOOKAHEAD. It is always acceptable to return the value zero, indicating that there are no known special properties. It is acceptable for the properties of the iterator to change depending on its state.