/*
* eXist Open Source Native XML Database
* Copyright (C) 2001-06 Wolfgang M. Meier
* wolfgang@exist-db.org
* http://exist.sourceforge.net
*
* 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., 675 Mass Ave, Cambridge, MA 02139, USA.
*
* $Id$
*/
package org.exist.xquery;
import org.exist.xquery.util.ExpressionDumper;
import org.exist.xquery.value.Item;
import org.exist.xquery.value.NumericValue;
import org.exist.xquery.value.Sequence;
import org.exist.xquery.value.Type;
/**
* A unary minus or plus.
*
* @author wolf
*/
public class UnaryExpr extends PathExpr {
private final int mode;
public UnaryExpr(XQueryContext context, int mode) {
super(context);
this.mode = mode;
}
public int returnsType() {
return Type.DECIMAL;
}
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();}
if(getLength() == 0)
{throw new XPathException(this, "unary expression requires an operand");}
Sequence result;
final Sequence item = getExpression(0).eval(contextSequence);
if (item.isEmpty())
{return item;}
NumericValue value = (NumericValue)item.convertTo(Type.NUMBER);
if(mode == Constants.MINUS)
{result = value.negate();}
else
{result = value;}
if (context.getProfiler().isEnabled())
{context.getProfiler().end(this, "", result);}
return result;
}
public void dump(ExpressionDumper dumper) {
if(mode == Constants.MINUS)
{dumper.display("-");}
else
{dumper.display("to be implemented");}
}
public String toString() {
if(mode == Constants.MINUS)
{return "-";}
else
{return("to be implemented");}
}
@Override
public Expression simplify() {
return this;
}
}