/*
* 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.Error;
import org.exist.xquery.util.ExpressionDumper;
import org.exist.xquery.value.BooleanValue;
import org.exist.xquery.value.Item;
import org.exist.xquery.value.NodeValue;
import org.exist.xquery.value.Sequence;
import org.exist.xquery.value.Type;
/**
* Implements node comparisons: is, isnot, <<, >>.
*
* @author Wolfgang Meier (wolfgang@exist-db.org)
*/
public class NodeComparison extends BinaryOp {
private final int relation;
/**
* @param context
*/
public NodeComparison(XQueryContext context, Expression left, Expression right, int relation) {
super(context);
this.relation = relation;
add(new DynamicCardinalityCheck(context, Cardinality.ZERO_OR_ONE, left,
new Error(Error.NODE_COMP_TYPE_MISMATCH)));
add(right);
//add(new DynamicCardinalityCheck(context, Cardinality.ZERO_OR_ONE, right,
// new Error(Error.NODE_COMP_TYPE_MISMATCH)));
//add(left);
}
/* (non-Javadoc)
* @see org.exist.xquery.PathExpr#getDependencies()
*/
public int getDependencies() {
return Dependency.CONTEXT_SET | Dependency.CONTEXT_ITEM;
}
/* (non-Javadoc)
* @see org.exist.xquery.AbstractExpression#getCardinality()
*/
public int getCardinality() {
return Cardinality.ZERO_OR_ONE;
}
/* (non-Javadoc)
* @see org.exist.xquery.BinaryOp#returnsType()
*/
public int returnsType() {
return Type.BOOLEAN;
}
/* (non-Javadoc)
* @see org.exist.xquery.Expression#eval(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();}
Sequence result;
final Sequence ls = getLeft().eval(contextSequence, contextItem);
final Sequence rs = getRight().eval(contextSequence, contextItem);
if (!ls.isEmpty() && !rs.isEmpty()) {
if (!Type.subTypeOf(ls.itemAt(0).getType(), Type.NODE))
{throw new XPathException(this, ErrorCodes.XPTY0004,
"left item is not a node; got '" +
Type.getTypeName(ls.itemAt(0).getType()) + "'");}
if (!Type.subTypeOf(rs.itemAt(0).getType(), Type.NODE))
{throw new XPathException(this, ErrorCodes.XPTY0004,
"right item is not a node; got '" +
Type.getTypeName(rs.itemAt(0).getType()) + "'");}
final NodeValue lv = (NodeValue)ls.itemAt(0);
final NodeValue rv = (NodeValue)rs.itemAt(0);
if (lv.getImplementationType() != rv.getImplementationType()) {
// different implementations : can't be the same nodes
result = BooleanValue.FALSE;
} else {
switch(relation) {
case Constants.IS:
result = lv.equals(rv) ? BooleanValue.TRUE : BooleanValue.FALSE;
break;
case Constants.ISNOT:
result = lv.equals(rv) ? BooleanValue.FALSE : BooleanValue.TRUE;
break;
case Constants.BEFORE:
result = lv.before(rv, false) ? BooleanValue.TRUE : BooleanValue.FALSE;
break;
case Constants.AFTER:
result = lv.after(rv, false) ? BooleanValue.TRUE : BooleanValue.FALSE;
break;
default:
throw new XPathException(this, "Illegal argument: unknown relation");
}
}
} else {
if (ls.isEmpty() && !rs.isEmpty()) {
if (!Type.subTypeOf(rs.getItemType(), Type.NODE))
{throw new XPathException(this, ErrorCodes.XPTY0004,
"The empty sequence cant be an atomic value");}
}
if (!ls.isEmpty() && rs.isEmpty()) {
if (!Type.subTypeOf(ls.getItemType(), Type.NODE))
{throw new XPathException(this, ErrorCodes.XPTY0004,
"The empty sequence cant be an atomic value");}
}
result = BooleanValue.EMPTY_SEQUENCE;
}
if (context.getProfiler().isEnabled())
{context.getProfiler().end(this, "", result);}
return result;
}
/* (non-Javadoc)
* @see org.exist.xquery.PathExpr#dump(org.exist.xquery.util.ExpressionDumper)
*/
public void dump(ExpressionDumper dumper) {
getLeft().dump(dumper);
dumper.display(' ').display(Constants.OPS[relation]).display(' ');
getRight().dump(dumper);
}
public String toString() {
final StringBuilder result = new StringBuilder();
result.append(getLeft().toString());
result.append(' ').append(Constants.OPS[relation]).append(' ');
result.append(getRight().toString());
return result.toString();
}
}