/* eXist Open Source Native XML Database
* Copyright (C) 2000-03, Wolfgang M. Meier (meier@ifs.tu-darmstadt.de)
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This library 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 Library General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* $Id$
*/
package org.exist.xquery;
import org.apache.log4j.Logger;
import org.exist.xquery.util.ExpressionDumper;
import org.exist.xquery.value.Item;
import org.exist.xquery.value.Sequence;
import org.exist.xquery.value.Type;
import org.exist.xquery.value.ValueSequence;
public class Union extends CombiningExpression {
private final static Logger LOG = Logger.getLogger(Union.class);
public Union(XQueryContext context, PathExpr left, PathExpr right) {
super(context, left, right);
}
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 lval = left.eval(contextSequence, contextItem);
Sequence rval = right.eval(contextSequence, contextItem);
lval.removeDuplicates();
rval.removeDuplicates();
Sequence result;
if (lval.isEmpty() && rval.isEmpty()) {
result = Sequence.EMPTY_SEQUENCE;
} else if(rval.isEmpty()) {
if(!Type.subTypeOf(lval.getItemType(), Type.NODE))
throw new XPathException(this, "Error XPTY0004 : union operand is not a node sequence");
result = lval;
} else if(lval.isEmpty()) {
if(!Type.subTypeOf(rval.getItemType(), Type.NODE))
throw new XPathException(this, "Error XPTY0004 : union operand is not a node sequence");
result = rval;
} else {
if(!(Type.subTypeOf(lval.getItemType(), Type.NODE) && Type.subTypeOf(rval.getItemType(), Type.NODE)))
throw new XPathException(this, "Error XPTY0004 : union operand is not a node sequence");
if (lval.isPersistentSet() && rval.isPersistentSet()) {
result = lval.toNodeSet().union(rval.toNodeSet());
} else {
ValueSequence values = new ValueSequence(true);
values.addAll(lval);
values.addAll(rval);
values.sortInDocumentOrder();
values.removeDuplicates();
result = values;
}
}
if (context.getProfiler().isEnabled())
context.getProfiler().end(this, "", result);
return result;
}
/* (non-Javadoc)
* @see org.exist.xquery.Expression#dump(org.exist.xquery.util.ExpressionDumper)
*/
public void dump(ExpressionDumper dumper) {
left.dump(dumper);
dumper.display(" union ");
right.dump(dumper);
}
public String toString() {
StringBuilder result = new StringBuilder();
result.append(left.toString());
result.append(" union ");
result.append(right.toString());
return result.toString();
}
public void accept(ExpressionVisitor visitor) {
visitor.visitUnionExpr(this);
}
}