/* eXist Open Source Native XML Database
* Copyright (C) 2001-06, Wolfgang M. Meier (wolfgang@exist-db.org)
*
* 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 "and".
*
* @author Wolfgang <wolfgang@exist-db.org>
*/
public class OpAnd extends LogicalOp {
public OpAnd(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());
}
Sequence result;
if (getLength() == 0)
result = Sequence.EMPTY_SEQUENCE;
else {
if (contextItem != null)
contextSequence = contextItem.toSequence();
boolean doOptimize = optimize;
if (contextSequence != null && !contextSequence.isPersistentSet())
doOptimize = false;
Expression left = getLeft();
Expression right = getRight();
if(doOptimize) {
NodeSet rl = left.eval(contextSequence, null).toNodeSet();
rl = rl.getContextNodes(left.getContextId());
// TODO: optimize and return false if rl.isEmpty() ?
NodeSet rr = right.eval(contextSequence, null).toNodeSet();
rr = rr.getContextNodes(right.getContextId());
result = rr.intersection(rl);
//<test>{() and ()}</test> has to return <test>false</test>
if (getParent() instanceof EnclosedExpr ||
//First, the intermediate PathExpr
((PathExpr)getParent()).getParent() == null) {
result = result.isEmpty() ? BooleanValue.FALSE : BooleanValue.TRUE;
}
} else {
boolean ls = left.eval(contextSequence).effectiveBooleanValue();
// immediately return false if the left operand is false
if (!ls)
result = BooleanValue.FALSE;
else {
boolean rs = right.eval(contextSequence).effectiveBooleanValue();
result = (ls && rs) ? BooleanValue.TRUE : BooleanValue.FALSE;
}
}
}
if (context.getProfiler().isEnabled())
context.getProfiler().end(this, "", result);
return result;
}
public void accept(ExpressionVisitor visitor) {
visitor.visitAndExpr(this);
}
/* (non-Javadoc)
* @see org.exist.xquery.PathExpr#dump(org.exist.xquery.util.ExpressionDumper)
*/
public void dump(ExpressionDumper dumper) {
if (getLength() == 0)
return;
getExpression(0).dump(dumper);
for (int i = 1; i < getLength(); i++) {
dumper.display(") and (");
getExpression(i).dump(dumper);
}
}
public String toString() {
if (getLength() == 0)
return "";
StringBuilder result = new StringBuilder("(");
result.append(getExpression(0).toString());
for (int i = 1; i < getLength(); i++) {
result.append(") and (");
result.append(getExpression(i).toString());
}
result.append(")");
return result.toString();
}
}