/**
* Copyright (c) 2013, Institute of Information Systems (Sven Groppe and contributors of LUPOSDATE), University of Luebeck
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification, are permitted provided that the
* following conditions are met:
*
* - Redistributions of source code must retain the above copyright notice, this list of conditions and the following
* disclaimer.
* - Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the
* following disclaimer in the documentation and/or other materials provided with the distribution.
* - Neither the name of the University of Luebeck nor the names of its contributors may be used to endorse or promote
* products derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
* GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package lupos.engine.operators.singleinput.sort.comparator;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.net.URISyntaxException;
import java.util.Collection;
import java.util.LinkedList;
import lupos.datastructures.bindings.Bindings;
import lupos.datastructures.items.Variable;
import lupos.datastructures.items.literal.LazyLiteral;
import lupos.datastructures.items.literal.Literal;
import lupos.datastructures.items.literal.TypedLiteral;
import lupos.datastructures.items.literal.TypedLiteralOriginalContent;
import lupos.engine.operators.singleinput.NotBoundException;
import lupos.engine.operators.singleinput.TypeErrorException;
import lupos.engine.operators.singleinput.filter.Filter;
import lupos.engine.operators.singleinput.filter.expressionevaluation.Helper;
import lupos.optimizations.sparql2core_sparql.SPARQLParserVisitorImplementationDumper;
import lupos.sparql1_1.ASTAs;
import lupos.sparql1_1.SimpleNode;
public class ComparatorAST implements ComparatorBindings {
/**
* Compares two given bindings as specified in SPARQL-specification
*/
protected lupos.sparql1_1.Node node;
public ComparatorAST(final lupos.sparql1_1.Node node) {
this.node = node;
}
/**
* This method is used in order to check whether or not a previous join can
* replace this sort operator by using MergeJoinSort (for optional
* analogous).
*
* @return the sort criterium as collection of variables or null if the sort
* criterium is not so simple!
*/
public Collection<Variable> getSortCriterium() {
final LinkedList<Variable> sortCriterium = new LinkedList<Variable>();
for (int i = 0; i < node.jjtGetNumChildren(); i++) {
final lupos.sparql1_1.Node n = node.jjtGetChild(i);
final int mod = 1;
if (n instanceof lupos.sparql1_1.ASTDescOrder) {
return null;
}
if (n instanceof lupos.sparql1_1.ASTVar) {
sortCriterium.add(new Variable(((lupos.sparql1_1.ASTVar) n)
.getName()));
} else
return null;
}
return sortCriterium;
}
/**
* Compares two bindings considering SPARQL-specifications
*
* @param arg0
* first Bindings to compare
* @param arg1
* second Bindings to compare
* @return simlar to any other integer based compare method: <br>
* -1 if l0 < l1<br>
* 1 if l0 > l1<br>
* 0 if l0 = l1<br>
* but modified, as result will be multiplicated by -1 if descending
* order has been chosen.
*/
public int compare(final Bindings arg0, final Bindings arg1) {
for (int i = 0; i < node.jjtGetNumChildren(); i++) {
lupos.sparql1_1.Node n = node.jjtGetChild(i);
if (n instanceof ASTAs) {
n=n.jjtGetChild(0);
}
int mod = 1;
if (n instanceof lupos.sparql1_1.ASTDescOrder) {
mod = -1;
i++;
n = node.jjtGetChild(i);
}
if (n instanceof lupos.sparql1_1.ASTAscOrder) {
i++;
n = node.jjtGetChild(i);
}
Object o0;
try {
o0 = Filter.staticEvalTree(arg0, n, null);
} catch (final NotBoundException e) {
o0 = null;
} catch (final TypeErrorException e) {
o0 = null;
}
Object o1;
try {
o1 = Filter.staticEvalTree(arg1, n, null);
} catch (final NotBoundException e) {
o1 = null;
} catch (final TypeErrorException e) {
o1 = null;
}
final Literal l0 = getLiteral(o0);
final Literal l1 = getLiteral(o1);
final int ret = intComp(l0, l1);
if (ret != 0)
return ret * mod;
}
return 0;
}
public static Literal getLiteral(final Object o) {
if (o instanceof Literal)
return (Literal) o;
if (o instanceof String)
try {
return TypedLiteralOriginalContent.createTypedLiteral(o
.toString(),
"<http://www.w3.org/2001/XMLSchema#string>");
} catch (final URISyntaxException e) {
return null;
}
else if (o instanceof BigInteger)
try {
return TypedLiteralOriginalContent.createTypedLiteral("\""
+ o.toString() + "\"",
"<http://www.w3.org/2001/XMLSchema#integer>");
} catch (final URISyntaxException e) {
return null;
}
else if (o instanceof BigDecimal)
try {
return TypedLiteralOriginalContent.createTypedLiteral("\""
+ o.toString() + "\"",
"<http://www.w3.org/2001/XMLSchema#decimal>");
} catch (final URISyntaxException e) {
return null;
}
else if (o instanceof Boolean)
try {
return TypedLiteralOriginalContent.createTypedLiteral("\""
+ o.toString() + "\"",
"<http://www.w3.org/2001/XMLSchema#boolean>");
} catch (final URISyntaxException e) {
return null;
}
return null;
}
/**
* Does the dirty work for compare
*
* @param l0
* first binding to compare
* @param l1
* second binding to compare
* @return simlar to any other integer based compare method: <br>
* -1 if l0 < l1<br>
* 1 if l0 > l1<br>
* 0 if l0 = l1
*/
public static int intComp(Literal l0, Literal l1) {
if (l0 instanceof LazyLiteral) {
if(l1 instanceof LazyLiteral){
// if the two lazy literals are equal, then we can avoid to materialize them!
if(((LazyLiteral)l0).getCode() == ((LazyLiteral)l1).getCode())
return 0;
}
l0 = ((LazyLiteral) l0).getLiteral();
}
if (l1 instanceof LazyLiteral)
l1 = ((LazyLiteral) l1).getLiteral();
// Order concerning only prim-variable
// Unbound second - But needs to be checked first
if (l0 == null || l1 == null) {
if (l0 == l1) {
return 0;
}
if (l0 == null) {
if (l1.isBlank()) {
return 1;
}
return -1;
} else {
if (l0.isBlank()) {
return -1;
}
return 1;
}
}
// Blanks first!!!
if (l0.isBlank() || l1.isBlank()) {
if (!l0.isBlank()) {
return 1;
}
if (!l1.isBlank()) {
return -1;
}
return l0.toString().compareTo(l1.toString());
}
// IRIs third
if ((l0.isURI()) || (l1.isURI())) {
if (!(l0.isURI())) {
return 1;
}
if (!(l1.isURI())) {
return -1;
}
return l0.toString().compareTo(l1.toString());
}
// this is undefined in the SPARQL specification, but we define the following order between RDF literals of different types:
// 1. Simple literals 2. language tagged literals 3. typed literals
// first simple literals:
if(l0.isSimpleLiteral() || l1.isSimpleLiteral()){
if (!(l0.isSimpleLiteral())) {
return 1;
}
if (!(l1.isSimpleLiteral())) {
return -1;
}
return l0.toString().compareTo(l1.toString());
}
// second language tagged literals
if(l0.isLanguageTaggedLiteral() || l1.isLanguageTaggedLiteral()){
if (!(l0.isLanguageTaggedLiteral())) {
return 1;
}
if (!(l1.isLanguageTaggedLiteral())) {
return -1;
}
return l0.toString().compareTo(l1.toString());
}
// third typed literals:
// Numeric comparison?
if (l0 instanceof TypedLiteral && l1 instanceof TypedLiteral) {
final TypedLiteral tl0 = (TypedLiteral) l0;
final TypedLiteral tl1 = (TypedLiteral) l1;
if (Helper.isNumeric(tl0.getType())
&& Helper.isNumeric(tl1.getType())) {
if (Helper.isInteger(tl0.getType())
&& Helper.isInteger(tl1.getType())) {
BigInteger a;
try {
a = Helper.getInteger(tl0);
} catch (final NumberFormatException e) {
a = null;
} catch (final TypeErrorException e) {
a = null;
}
BigInteger b;
try {
b = Helper.getInteger(tl1);
} catch (final NumberFormatException e) {
b = null;
} catch (final TypeErrorException e) {
b = null;
}
if (a == null) {
if (b == null){
return l0.toString().compareTo(l1.toString());
} else {
return 1;
}
} else if (b == null) {
return -1;
} else {
final int comp = a.compareTo(b);
return comp;
}
} else { // decimal comparison...
BigDecimal a;
try {
a = Helper.getBigDecimal(tl0);
} catch (final NumberFormatException e) {
a = null;
} catch (final TypeErrorException e) {
a = null;
}
BigDecimal b;
try {
b = Helper.getBigDecimal(tl1);
} catch (final NumberFormatException e) {
b = null;
} catch (final TypeErrorException e) {
b = null;
}
if (a == null) {
if (b == null){
return l0.toString().compareTo(l1.toString());
} else {
return 1;
}
} else if (b == null){
return -1;
} else {
final int comp = a.compareTo(b);
return comp;
}
}
}
}
// else simple String-compare
return l0.toString().compareTo(l1.toString());
}
/**
* @return returns a String-representation of this comperator
*/
@Override
public String toString() {
final SPARQLParserVisitorImplementationDumper filterDumper = new SPARQLParserVisitorImplementationDumper();
return (String) filterDumper.visit((SimpleNode) node);
}
}