/**
* Execute the compiled Query, returning the first item in the result. This is useful where it is
* known that the expression will only return a singleton value (for example, a single node, or a
* boolean).
*
* @param env Provides the dynamic query evaluation context
* @return The first item in the sequence returned by the expression. If the expression returns an
* empty sequence, this method returns null. Otherwise, it returns the first item in the
* result sequence, represented as a Java object using the same mapping as for the {@link
* XQueryExpression#evaluate evaluate} method
*/
public Object evaluateSingle(DynamicQueryContext env) throws XPathException {
if (isUpdating) {
throw new XPathException("Cannot call evaluateSingle() on an updating query");
}
SequenceIterator iterator = iterator(env);
Item item = iterator.next();
if (item == null) {
return null;
}
return Value.convertToJava(item);
}
/**
* Execute a the compiled Query, returning the results as a List.
*
* @param env Provides the dynamic query evaluation context
* @return The results of the expression, as a List. The List represents the sequence of items
* returned by the expression. Each item in the list will either be an object representing a
* node, or an object representing an atomic value. For the types of Java object that may be
* returned, see the description of the {@link org.orbeon.saxon.xpath.XPathEvaluator#evaluate
* evaluate} method of class XPathProcessor
*/
public List evaluate(DynamicQueryContext env) throws XPathException {
if (isUpdating) {
throw new XPathException("Cannot call evaluate() on an updating query");
}
SequenceIterator iterator = iterator(env);
ArrayList list = new ArrayList(100);
while (true) {
Item item = iterator.next();
if (item == null) {
return list;
}
list.add(Value.convertToJava(item));
}
}