Package javax.xml.xquery

Interface XQResultItem

  • All Superinterfaces:
    XQItem, XQItemAccessor
    All Known Implementing Classes:
    SaxonXQItem
    public interface XQResultItem
extends XQItem
    This interface represents an immutable item object obtained from an XQResultSequence using the getItem method.

    A forward only result sequence does not support calling the getter methods multiple times on the same item. To work around this case, the getItem method can be used to obtain a result item and then getter methods may be called multiple times on this item.

    The XQResultItem object is dependent on the connection, expression and the sequence from which it was created and is only valid for the duration of those objects. Thus, if any one of those objects is closed, this XQResultItem object will be implicitly closed, and it can no longer be used. Similarly re-executing the expression also implicitly closes the associated result sequences, which in turn implicitly closes this result item.

    An XQJ driver is not required to provide finalizer methods for the connection and other objects. Hence it is strongly recommended that users call close method explicitly to free any resources. It is also recommended that they do so under a final block to ensure that the object is closed even when there are exceptions. Not closing this object implicitly or explicitly might result in serious memory leaks.

    Example - 

    
  XQPreparedExpression expr = conn.prepareExpression("for $i ..");
  XQResultSequence result = expr.executeQuery();

  // posititioned before the first item
  while (result.next())
  {
    XQResultItem item = result.getItem();
    // perform multiple gets on this item
    // get DOM
    org.w3.dom.Node node = item.getNode();
    // get SAX
    item.writeItemToSAX(saxHandler);

    item.close();  // good practice.  Item will get implicitly closed
                   // when the expression,  connection or sequence is closed.
  }

  result.close(); // explicitly close the result sequence

    • Method Detail

      • getConnection

        XQConnection getConnection()
                    throws XQException
        Gets the XQuery connection associated with this result item
        Returns:
        the connection associated with this result item
        Throws:
        XQException - if the result item is in a closed state