/**
* Checks if the specified expression yields an element. Returns the element or throws an
* exception.
*
* @param ex expression to be evaluated
* @param qc query context
* @return binary item
* @throws QueryException query exception
*/
protected final ANode toElem(final Expr ex, final QueryContext qc) throws QueryException {
return (ANode) checkType(ex.item(qc, info), NodeType.ELM);
}
/**
* Checks if the specified expression yields a non-empty item. Returns the item or throws an
* exception.
*
* @param ex expression to be evaluated
* @param qc query context
* @param type expected type
* @return item
* @throws QueryException query exception
*/
private Item toItem(final Expr ex, final QueryContext qc, final Type type) throws QueryException {
return checkNoEmpty(ex.item(qc, info), type);
}
/**
* Checks if the specified expression yields a node or {@code null}. Returns the node, {@code
* null}, or throws an exception.
*
* @param ex expression to be evaluated
* @param qc query context
* @return node or {@code null}
* @throws QueryException query exception
*/
protected final ANode toEmptyNode(final Expr ex, final QueryContext qc) throws QueryException {
final Item it = ex.item(qc, info);
return it == null ? null : toNode(it);
}
/**
* Checks if the evaluated expression yields a non-empty item. Returns the item or throws an
* exception.
*
* @param ex expression to be evaluated
* @param qc query context
* @return item
* @throws QueryException query exception
*/
protected final Item toItem(final Expr ex, final QueryContext qc) throws QueryException {
return checkNoEmpty(ex.item(qc, info));
}
/**
* Checks if the specified expression yields a node. Returns the boolean or throws an exception.
*
* @param ex expression to be evaluated
* @param qc query context
* @return node
* @throws QueryException query exception
*/
protected final ANode toNode(final Expr ex, final QueryContext qc) throws QueryException {
return toNode(checkNoEmpty(ex.item(qc, info), NodeType.NOD));
}