/*
* eXist Open Source Native XML Database
* Copyright (C) 2001-2009 The eXist Project
* http://exist-db.org
*
* 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.fn;
import org.exist.dom.QName;
import org.exist.xquery.Cardinality;
import org.exist.xquery.Dependency;
import org.exist.xquery.Function;
import org.exist.xquery.FunctionSignature;
import org.exist.xquery.Profiler;
import org.exist.xquery.XPathException;
import org.exist.xquery.XQueryContext;
import org.exist.xquery.value.BooleanValue;
import org.exist.xquery.value.FunctionReturnSequenceType;
import org.exist.xquery.value.FunctionParameterSequenceType;
import org.exist.xquery.value.Item;
import org.exist.xquery.value.Sequence;
import org.exist.xquery.value.SequenceType;
import org.exist.xquery.value.Type;
/**
* Implements function fn:exists.
*
* @author Wolfgang Meier (wolfgang@exist-db.org)
*/
public class FunExists extends Function {
public final static FunctionSignature signature =
new FunctionSignature(
new QName("exists", Function.BUILTIN_FUNCTION_NS),
"Returns true if the argument $items is not the empty sequence, " +
"false otherwise.",
new SequenceType[] {
new FunctionParameterSequenceType("items", Type.ITEM, Cardinality.ZERO_OR_MORE, "The item sequence")
},
new FunctionReturnSequenceType(Type.BOOLEAN, Cardinality.EXACTLY_ONE, "true() if not the empty-sequence, false() otherwise"));
/**
* @param context
*/
public FunExists(XQueryContext context) {
super(context, signature);
}
/* (non-Javadoc)
* @see org.exist.xquery.Expression#eval(org.exist.dom.DocumentSet, org.exist.xquery.value.Sequence, org.exist.xquery.value.Item)
*/
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());}
}
//if(contextItem != null)
//contextSequence = contextItem.toSequence();
final Sequence seq = getArgument(0).eval(contextSequence, contextItem);
final Sequence result = seq.isEmpty() ? BooleanValue.FALSE : BooleanValue.TRUE;
if (context.getProfiler().isEnabled())
{context.getProfiler().end(this, "", result);}
return result;
}
}