javax.xml.xquery

Interface XQResultSequence

All Superinterfaces:

XQItemAccessor, XQSequence

All Known Implementing Classes:

SaxonXQForwardSequence, SaxonXQSequence

public interface XQResultSequence
extends XQSequence

This interface represents a sequence of items obtained as a result of evaluation XQuery expressions. The result sequence is tied to the XQconnection object on which the expression was evaluated.

This sequence can be obtained by performing an executeQuery on the expression object. It represents a cursor-like interface.

The XQResultSequence object is dependent on the connection and the expression 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 XQResultSequence object will be implicitly closed and it can no longer be used. Similarly re-executing the expression also implicitly closes the associated result sequences.

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.

When the XQResultSequence is closed any XQResultItem objects obtained from it are also implicitly closed.

Example -

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

  // create the ItemTypes for string and integer
  XQItemType strType = conn.createAtomicType(XQItemType.XQBASETYPE_STRING);
  XQItemType intType = conn.createAtomicType(XQItemType.XQBASETYPE_INT);

  // posititioned before the first item
  while (result.next())
  {
    XQItemType type = result.getItemType();

    // If string, then get the string value out
    if (type.equals(strType))
      String str = result.getAtomicValue();
    else if (type.equals(intType))  // if it is an integer..
      int intval = result.getInt();
      ...
  }

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

 

Method Summary

Methods

Modifier and Type	Method and Description
XQConnection	getConnection() Gets the XQuery connection associated with this result sequence

Methods inherited from interface javax.xml.xquery.XQSequence

absolute, afterLast, beforeFirst, close, count, first, getItem, getPosition, getSequenceAsStream, getSequenceAsString, isAfterLast, isBeforeFirst, isClosed, isFirst, isLast, isOnItem, isScrollable, last, next, previous, relative, writeSequence, writeSequence, writeSequenceToResult, writeSequenceToSAX

Methods inherited from interface javax.xml.xquery.XQItemAccessor

getAtomicValue, getBoolean, getByte, getDouble, getFloat, getInt, getItemAsStream, getItemAsString, getItemType, getLong, getNode, getNodeUri, getObject, getShort, instanceOf, writeItem, writeItem, writeItemToResult, writeItemToSAX

Method Detail

getConnection

XQConnection getConnection()
                           throws XQException

Gets the XQuery connection associated with this result sequence

Returns:

the connection associated with this result sequence

Throws:

XQException - if the result sequence is in a closed state