/*
* eXist Open Source Native XML Database
* Copyright (C) 2001-2009 The eXist team
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software Foundation
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* $Id$
*/
package org.exist.xquery.functions;
import org.exist.dom.QName;
import org.exist.xquery.*;
import org.exist.xquery.value.FunctionParameterSequenceType;
import org.exist.xquery.value.FunctionReturnSequenceType;
import org.exist.xquery.value.Item;
import org.exist.xquery.value.Sequence;
import org.exist.xquery.value.SequenceIterator;
import org.exist.xquery.value.SequenceType;
import org.exist.xquery.value.Type;
import org.exist.xquery.value.ValueSequence;
/**
* Implements the fn:reverse function.
*
* @author <a href="mailto:piotr@ideanest.com">Piotr Kaminski</a>
*/
public class FunReverse extends Function {
public final static FunctionSignature signature =
new FunctionSignature(
new QName("reverse", Function.BUILTIN_FUNCTION_NS),
"Reverses the order of items in a sequence. If the argument is an empty" +
"sequence, the empty sequence is returned.",
new SequenceType[] {new FunctionParameterSequenceType("arg", Type.ITEM, Cardinality.ZERO_OR_MORE, "The sequence to reverse")},
new FunctionReturnSequenceType(Type.ITEM, Cardinality.ZERO_OR_MORE, "the reverse order sequence"));
public FunReverse(XQueryContext context) {
super(context, signature);
}
public void analyze(AnalyzeContextInfo contextInfo) throws XPathException {
// statically check the argument list
checkArguments();
// call analyze for each argument
inPredicate = (contextInfo.getFlags() & IN_PREDICATE) > 0;
contextId = contextInfo.getContextId();
contextInfo.setParent(this);
AnalyzeContextInfo argContextInfo = new AnalyzeContextInfo(contextInfo);
getArgument(0).analyze(argContextInfo);
contextInfo.setStaticReturnType(argContextInfo.getStaticReturnType());
}
public Sequence eval(Sequence contextSequence, Item contextItem) throws XPathException {
if (context.getProfiler().isEnabled()) {
context.getProfiler().start(this);
context.getProfiler().message(this, Profiler.DEPENDENCIES, "DEPENDENCIES", Dependency.getDependenciesName(this.getDependencies()));
if (contextSequence != null)
context.getProfiler().message(this, Profiler.START_SEQUENCES, "CONTEXT SEQUENCE", contextSequence);
if (contextItem != null)
context.getProfiler().message(this, Profiler.START_SEQUENCES, "CONTEXT ITEM", contextItem.toSequence());
}
Sequence result;
Sequence seq = getArguments(contextSequence, contextItem)[0];
if (seq.isEmpty())
result = Sequence.EMPTY_SEQUENCE;
else {
Sequence tmp = new ValueSequence();
Item item;
for(SequenceIterator i = seq.iterate(); i.hasNext(); ) {
item = i.nextItem();
tmp.add(item);
}
result = new ValueSequence();
for (int i = seq.getItemCount() - 1; i >= 0; i--) {
result.add(tmp.itemAt(i));
}
}
if (context.getProfiler().isEnabled())
context.getProfiler().end(this, "", result);
return result;
}
}