/*
* 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.Sequence;
import org.exist.xquery.value.SequenceIterator;
import org.exist.xquery.value.Type;
import org.exist.xquery.value.ValueSequence;
import java.util.Set;
import java.util.TreeSet;
/**
* @author Wolfgang Meier (wolfgang@exist-db.org)
*/
public class Intersection extends CombiningExpression {
/**
* @param context
*/
public Intersection(XQueryContext context, PathExpr left, PathExpr right) {
super(context, left, right);
}
/* (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());}
}
final Sequence lval = left.eval(contextSequence, contextItem);
final Sequence rval = right.eval(contextSequence, contextItem);
lval.removeDuplicates();
rval.removeDuplicates();
Sequence result;
if (lval.isEmpty() || rval.isEmpty())
{result = Sequence.EMPTY_SEQUENCE;}
else {
if(!(Type.subTypeOf(lval.getItemType(), Type.NODE) && Type.subTypeOf(rval.getItemType(), Type.NODE)))
{throw new XPathException(this, ErrorCodes.XPTY0004, "intersect operand is not a node sequence");}
if (lval.isPersistentSet() && rval.isPersistentSet())
{result = lval.toNodeSet().intersection(rval.toNodeSet());}
else {
result = new ValueSequence(true);
final Set<Item> set = new TreeSet<Item>();
for (final SequenceIterator i = lval.unorderedIterator(); i.hasNext(); )
set.add(i.nextItem());
for (final SequenceIterator i = rval.unorderedIterator(); i.hasNext(); ) {
final Item next = i.nextItem();
if (set.contains(next))
{result.add(next);}
}
result.removeDuplicates();
}
}
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(" intersect ");
right.dump(dumper);
}
public String toString() {
final StringBuilder result = new StringBuilder();
result.append(left.toString());
result.append(" intersect ");
result.append(right.toString());
return result.toString();
}
public void accept(ExpressionVisitor visitor) {
visitor.visitIntersectionExpr(this);
}
}