/**
Copyright (C) SYSTAP, LLC DBA Blazegraph 2006-2016. All rights reserved.
Contact:
SYSTAP, LLC DBA Blazegraph
2501 Calvert ST NW #106
Washington, DC 20008
licenses@blazegraph.com
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
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 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
*/
package com.bigdata.rdf.internal.constraints;
import java.util.Map;
import org.apache.log4j.Logger;
import org.openrdf.model.Literal;
import org.openrdf.query.algebra.Compare.CompareOp;
import org.openrdf.query.algebra.evaluation.ValueExprEvaluationException;
import org.openrdf.query.algebra.evaluation.util.QueryEvaluationUtil;
import com.bigdata.bop.BOp;
import com.bigdata.bop.IBindingSet;
import com.bigdata.bop.IValueExpression;
import com.bigdata.bop.NV;
import com.bigdata.bop.solutions.IVComparator;
import com.bigdata.rdf.error.SparqlTypeErrorException;
import com.bigdata.rdf.internal.IV;
import com.bigdata.rdf.internal.impl.literal.AbstractLiteralIV;
import com.bigdata.rdf.internal.impl.literal.LiteralExtensionIV;
import com.bigdata.rdf.internal.impl.literal.PackedLongIV;
import com.bigdata.rdf.internal.impl.literal.XSDIntegerIV;
import com.bigdata.rdf.model.BigdataValue;
import com.bigdata.rdf.sparql.ast.FilterNode;
/**
* Perform open-world value comparison operations per the SPARQL spec (the LT
* operator). This does NOT implement the broader ordering for ORDER BY. That is
* handled by {@link IVComparator}.
*
* @see <a
* href="http://www.w3.org/TR/2013/REC-sparql11-query-20130321/#op_lt"><</a>
*
* @see IVComparator
*/
public class CompareBOp extends XSDBooleanIVValueExpression
implements INeedsMaterialization {
/**
*
*/
private static final long serialVersionUID = 5661497748051783499L;
private static final transient Logger log = Logger
.getLogger(CompareBOp.class);
public interface Annotations extends XSDBooleanIVValueExpression.Annotations {
/**
* The compare operator, which is a {@link CompareOp} enum value.
*/
String OP = CompareBOp.class.getName() + ".op";
}
@SuppressWarnings("rawtypes")
public CompareBOp(final IValueExpression<? extends IV> left,
final IValueExpression<? extends IV> right, final CompareOp op) {
this(new BOp[] { left, right }, NV.asMap(Annotations.OP, op));
}
/**
* Required shallow copy constructor.
*/
public CompareBOp(final BOp[] args, final Map<String, Object> anns) {
super(args, anns);
if (args.length != 2 || args[0] == null || args[1] == null
|| getProperty(Annotations.OP) == null) {
throw new IllegalArgumentException();
}
if (log.isDebugEnabled()) {
log.debug(toString());
}
}
/**
* Constructor required for {@link com.bigdata.bop.BOpUtility#deepCopy(FilterNode)}.
*/
public CompareBOp(final CompareBOp op) {
super(op);
}
public CompareOp op() {
return (CompareOp) getRequiredProperty(Annotations.OP);
}
public static boolean compare(
final IV<BigdataValue, ?> left,
final IV<BigdataValue, ?> right,
final CompareOp op) {
if (log.isDebugEnabled()) {
log.debug(left);
log.debug(right);
}
// final BigdataValue val1 = left.getValue();
// final BigdataValue val2 = right.getValue();
//
// try {
//
// // use the Sesame implementation directly
// final boolean accept = QueryEvaluationUtil.compare(val1, val2, op);
//
// if (log.isDebugEnabled()) {
// log.debug(accept);
// }
//
// return accept;
//
// } catch (Exception ex) {
//
// if (log.isDebugEnabled()) {
// log.debug("exception: " + ex);
// }
//
// throw new SparqlTypeErrorException();
//
// }
if (left.isLiteral() && right.isLiteral()) {
// Both left and right argument is a Literal
return compareLiterals(left, right, op);
}
else {
// All other value combinations
switch (op) {
case EQ:
return valuesEqual(left, right);
case NE:
return !valuesEqual(left, right);
default:
throw new SparqlTypeErrorException();
}
}
}
private static boolean isRealTermId(final IV iv) {
return !iv.isInline() && !iv.isNullIV();
}
private static boolean compareLiterals(
final IV<BigdataValue, ?> left,
final IV<BigdataValue, ?> right,
final CompareOp op) {
/*
* Handle the special case where we have exact termId equality. This
* only works if both are "real" termIds (i.e. not mock IVs).
*/
if (op == CompareOp.EQ && isRealTermId(left) && isRealTermId(right)) {
if (left.equals(right)) {
return true;
}
}
/*
* We want to special case the LiteralExtensionIV, which
* handles xsd:dateTime. If we defer to Sesame for this, we will be
* forced into materialization because the first step in Sesame's
* evaluation is to get the datatype (requires materialization for
* LiteralExtensionIV).
*/
if (left instanceof LiteralExtensionIV &&
right instanceof LiteralExtensionIV) {
@SuppressWarnings("rawtypes")
final IV leftDatatype = ((LiteralExtensionIV) left).getExtensionIV();
@SuppressWarnings("rawtypes")
final IV rightDatatype = ((LiteralExtensionIV) right).getExtensionIV();
if (leftDatatype.equals(rightDatatype)) {
final boolean accept =
_accept(left.compareTo(right), op);
if (log.isDebugEnabled()) {
log.debug(accept);
}
return accept;
}
}
/**
* Handle LiteralExtensionIVs that support comparison with built-in datatypes.
* These types are handled by conversion into a built-in datatype, which can be checked
* by Sesame's QueryEvaluationUtil.
*/
Literal l1 = null;
Literal l2 = null;
if (left instanceof LiteralExtensionIV || right instanceof LiteralExtensionIV) {
/**
* We caught the case where both left and right are LiteralExtensionIVs
* earlier, so we can be sure that exactly one of the is a LiteralExtensionIVs.
*/
boolean leftIsLiteralExtensionIV = left instanceof LiteralExtensionIV;
@SuppressWarnings("rawtypes")
final AbstractLiteralIV delegate =
leftIsLiteralExtensionIV ?
((LiteralExtensionIV) left).getDelegate():
((LiteralExtensionIV) right).getDelegate();
if (delegate !=null) {
Literal delegateAsBuiltInLiteral = null;
if (delegate instanceof PackedLongIV) {
@SuppressWarnings("rawtypes")
final PackedLongIV iv = (PackedLongIV)delegate;
delegateAsBuiltInLiteral = new XSDIntegerIV<>(iv.integerValue());
} // else: add other cases here in future
// set left-hand or right-hand side expression
if (leftIsLiteralExtensionIV) {
l1 = delegateAsBuiltInLiteral; // may remain null
} else {
l2 = delegateAsBuiltInLiteral; // may remanin null
}
}
}
/*
* Now that the IVs implement the right openrdf interfaces,
* we should be able to mix and match inline with non-inline,
* using either the IV directly or its materialized value.
*/
l1 = l1==null ? asLiteral(left) : l1;
l2 = l2==null ? asLiteral(right) : l2;
if (log.isDebugEnabled()) {
log.debug(l1);
log.debug(l2);
}
try {
// use the Sesame implementation directly
final boolean accept =
QueryEvaluationUtil.compareLiterals(l1, l2, op);
if (log.isDebugEnabled()) {
log.debug(accept);
}
return accept;
} catch (ValueExprEvaluationException ex) {
if (log.isDebugEnabled()) {
log.debug("exception: " + ex);
}
throw new SparqlTypeErrorException();
}
}
private static boolean valuesEqual(
final IV<?, ?> left, final IV<?, ?> right) {
// must be the same type of value (e.g. both URIs, both BNodes, etc)
if (left.getVTE() != right.getVTE()) {
return false;
}
/*
* We can't use IV.equals() when we have a null IV. A null IV might
* have a materialized value that matches a term id in the database.
* Different IVs, same materialized value (this can happen via the
* datatype or str operator, anything that mints a new Value during
* query evaluation).
*/
if (left.isNullIV() || right.isNullIV()) {
return asValue(left).equals(asValue(right));
} else {
return left.equals(right);
}
}
@SuppressWarnings({ "rawtypes", "unchecked" })
public boolean accept(final IBindingSet s) {
final IV left = get(0).get(s);
final IV right = get(1).get(s);
// not yet bound
if (left == null || right == null)
throw new SparqlTypeErrorException();
if (log.isDebugEnabled()) {
log.debug("left: " + left);
log.debug("right: " + right);
log.debug("left value: " + (left.hasValue() ? left.getValue() : null));
log.debug("right value: " + (right.hasValue() ? right.getValue() : null));
}
return compare(left, right, op());
}
static protected boolean _accept(final int compare, final CompareOp op) {
switch(op) {
case EQ:
return compare == 0;
case NE:
return compare != 0;
case GT:
return compare > 0;
case GE:
return compare >= 0;
case LT:
return compare < 0;
case LE:
return compare <= 0;
default:
throw new UnsupportedOperationException();
}
}
/**
* The CompareBOp can work with non-materialized terms in the case of
* inline numerical compare operations. It is only when the bop encounters
* non-inlined numerics or needs to compare strings that it needs
* materialized terms.
*/
public Requirement getRequirement() {
return INeedsMaterialization.Requirement.SOMETIMES;
}
}