Package com.saxonica.ee.bytecode.iter

Class CompiledFilterIterator

  • All Implemented Interfaces:
    java.io.Closeable, java.lang.AutoCloseable, SequenceIterator
    public abstract class CompiledFilterIterator
extends java.lang.Object
implements SequenceIterator
    A CompiledFilterIterator filters an input sequence using a filter expression.

    • Constructor Detail

      • CompiledFilterIterator

        public CompiledFilterIterator()
        Zero-argument constructor (used by generated bytecode)

    • Method Detail

      • setSequence

        public final void setSequence​(SequenceIterator base,
                              XPathContext context)
        Set the base iterator and context
        Parameters:
        base - the iterator over the sequence to be filtered
        context - the context in which the (outer) filter expression is evaluated

      • next

        public final Item next()
                throws XPathException
        Get the next item if there is one
        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

      • matches

        protected abstract boolean matches()
                            throws XPathException
        Determine whether the context item matches the filter predicate
        Returns:
        true if the context item matches
        Throws:
        XPathException - if an error occurs evaluating the predicate

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