package client.net.sf.saxon.ce.functions;
import client.net.sf.saxon.ce.expr.StaticProperty;
import client.net.sf.saxon.ce.expr.XPathContext;
import client.net.sf.saxon.ce.om.SequenceIterator;
import client.net.sf.saxon.ce.trans.XPathException;
import client.net.sf.saxon.ce.type.ItemType;
import client.net.sf.saxon.ce.type.TypeHierarchy;
import client.net.sf.saxon.ce.value.SequenceExtent;
/**
* Implement XPath function fn:reverse()
*/
public class Reverse extends SystemFunction {
public Reverse newInstance() {
return new Reverse();
}
/**
* Determine the item type of the value returned by the function
*
* @param th the type hierarchy cache
*/
public ItemType getItemType(TypeHierarchy th) {
return argument[0].getItemType(th);
}
public int computeSpecialProperties() {
int baseProps = argument[0].getSpecialProperties();
if ((baseProps & StaticProperty.REVERSE_DOCUMENT_ORDER) != 0) {
return (baseProps &
(~StaticProperty.REVERSE_DOCUMENT_ORDER)) |
StaticProperty.ORDERED_NODESET;
} else if ((baseProps & StaticProperty.ORDERED_NODESET) != 0) {
return (baseProps &
(~StaticProperty.ORDERED_NODESET)) |
StaticProperty.REVERSE_DOCUMENT_ORDER;
} else {
return baseProps;
}
}
public SequenceIterator iterate(XPathContext context) throws XPathException {
SequenceIterator forwards = argument[0].iterate(context);
return getReverseIterator(forwards);
}
public static SequenceIterator getReverseIterator(SequenceIterator forwards) throws XPathException {
SequenceExtent extent = new SequenceExtent(forwards);
return extent.reverseIterate();
}
}
// This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0.
// If a copy of the MPL was not distributed with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
// This Source Code Form is “Incompatible With Secondary Licenses”, as defined by the Mozilla Public License, v. 2.0.