com.trolltech.qt.xmlpatterns
Class QXmlResultItems
java.lang.Object
com.trolltech.qt.internal.QSignalEmitterInternal
com.trolltech.qt.QSignalEmitter
com.trolltech.qt.QtJambiObject
com.trolltech.qt.xmlpatterns.QXmlResultItems
- All Implemented Interfaces:
- QtJambiInterface
public class QXmlResultItems
- extends QtJambiObject
The QXmlResultItems
class iterates through the results of evaluating an XQuery in QXmlQuery
. QXmlResultItems
presents the evaluation of an associated query as a sequence of QXmlItems
. The sequence is traversed by repeatedly calling next()
, which actually produces the sequence by lazy evaluation of the query.
QXmlQuery query = new QXmlQuery();
query.setQuery("<e/>, 1, 'two'");
QXmlResultItems result = new QXmlResultItems();
if(query.isValid())
{
query.evaluateToResult(result);
QXmlItem item = result.next();
while(!item.isNull())
{
// Use item
item = result.next();
}
if(result.hasError())
throw new RuntimeException("Runtime error!");
}
An effect of letting next()
produce the sequence by lazy evaluation is that a query error can occur on any call to next()
. If an error occurs, both next()
and current()
will return the null QXmlItem
, and hasError()
will return true. QXmlResultItems
can be thought of as an "iterator" that traverses the sequence of query results once, in the forward direction. Each call to next()
advances the iterator to the next QXmlItem
in the sequence and returns it, and current()
always returns the QXmlItem
that next()
returned the last time it was called.
See also:
QXmlItem::isNode()
, QXmlItem::isAtomicValue()
, and QXmlNodeModelIndex
.
Nested classes/interfaces inherited from class com.trolltech.qt.QSignalEmitter |
QSignalEmitter.AbstractSignal, QSignalEmitter.Signal0, QSignalEmitter.Signal1, QSignalEmitter.Signal2, QSignalEmitter.Signal3, QSignalEmitter.Signal4, QSignalEmitter.Signal5, QSignalEmitter.Signal6, QSignalEmitter.Signal7, QSignalEmitter.Signal8, QSignalEmitter.Signal9 |
Nested classes/interfaces inherited from class com.trolltech.qt.internal.QSignalEmitterInternal |
com.trolltech.qt.internal.QSignalEmitterInternal.AbstractSignalInternal |
Fields inherited from class com.trolltech.qt.internal.QSignalEmitterInternal |
currentSender |
Method Summary |
QXmlItem |
current()
Returns the current item. |
boolean |
hasError()
If an error occurred during evaluation of the query, true is returned. |
QXmlItem |
next()
Returns the next result in the sequence produced by lazy evaluation of the associated query. |
Methods inherited from class com.trolltech.qt.internal.QSignalEmitterInternal |
__qt_signalInitialization |
Methods inherited from class java.lang.Object |
clone, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
QXmlResultItems
public QXmlResultItems()
- Constructs an instance of
QXmlResultItems
.
current
public final QXmlItem current()
- Returns the current item. The current item is the last item that was produced and returned by
next()
. Returns a null QXmlItem
if there is no associated QXmlQuery
.
hasError
public final boolean hasError()
- If an error occurred during evaluation of the query, true is returned.
Returns false if query evaluation has been done.
next
public final QXmlItem next()
- Returns the next result in the sequence produced by lazy evaluation of the associated query. When the returned
QXmlItem
is null, either the evaluation terminated normally without producing another result, or an error occurred. Call hasError()
to determine whether the null item was caused by normal termination or by an error. Returns a null QXmlItem
if there is no associated QXmlQuery
.