/* 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.exist.dom.NodeSet;
import org.exist.xquery.util.ExpressionDumper;
import org.exist.xquery.value.BooleanValue;
import org.exist.xquery.value.Item;
import org.exist.xquery.value.Sequence;
/**
* Boolean operator "or".
*
* @author Wolfgang <wolfgang@exist-db.org>
*/
public class OpOr extends LogicalOp {
public OpOr(XQueryContext context) {
super(context);
}
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 (getLength() == 0)
{return Sequence.EMPTY_SEQUENCE;}
if (contextItem != null)
{contextSequence = contextItem.toSequence();}
boolean doOptimize = optimize;
if (contextSequence != null && !contextSequence.isPersistentSet())
{doOptimize = false;}
Sequence result;
final Expression left = getLeft();
final Expression right = getRight();
final Sequence ls = left.eval(contextSequence, null);
// first check if left operand is a persistent set
doOptimize = doOptimize && (ls.isPersistentSet() || ls.isEmpty());
if (doOptimize) {
// yes: try to optimize by looking at right operand
final Sequence rs = right.eval(contextSequence, null);
if (rs.isPersistentSet() || rs.isEmpty()) {
NodeSet rl = ls.toNodeSet();
rl = rl.getContextNodes(contextId);
NodeSet rr = rs.toNodeSet();
rr = rr.getContextNodes(contextId);
result = rl.union(rr);
//<test>{() or ()}</test> should return <test>false</test>
if (getParent() instanceof EnclosedExpr ||
//First, the intermediate PathExpr
(getParent() != null && getParent().getParent() == null)) {
result = result.isEmpty() ? BooleanValue.FALSE : BooleanValue.TRUE;
}
} else {
// fall back
final boolean rl = ls.effectiveBooleanValue();
if (rl) {
result = BooleanValue.TRUE;
} else {
final boolean rr = rs.effectiveBooleanValue();
result = rl || rr ? BooleanValue.TRUE : BooleanValue.FALSE;
}
}
} else {
// no: default evaluation based on boolean value
final boolean rl = ls.effectiveBooleanValue();
if (rl) {
result = BooleanValue.TRUE;
} else {
final Sequence rs = right.eval(contextSequence, null);
final boolean rr = rs.effectiveBooleanValue();
result = rl || rr ? BooleanValue.TRUE : BooleanValue.FALSE;
}
}
if (context.getProfiler().isEnabled())
{context.getProfiler().end(this, "", result);}
return result;
}
public void accept(ExpressionVisitor visitor) {
visitor.visitOrExpr(this);
}
/* (non-Javadoc)
* @see org.exist.xquery.PathExpr#dump(org.exist.xquery.util.ExpressionDumper)
*/
public void dump(ExpressionDumper dumper) {
if (getLength() == 0)
{return;}
dumper.display("(");
getExpression(0).dump(dumper);
for (int i = 1; i < getLength(); i++) {
dumper.display(") or (");
getExpression(i).dump(dumper);
}
dumper.display(")");
}
public String toString() {
if (getLength() == 0)
{return "";}
final StringBuilder result = new StringBuilder("(");
result.append(getExpression(0).toString());
for (int i = 1; i < getLength(); i++) {
result.append(") or (");
result.append(getExpression(i).toString());
}
result.append(")");
return result.toString();
}
}