/**
* 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;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import lupos.datastructures.bindings.Bindings;
import lupos.datastructures.bindings.BindingsFactory;
import lupos.datastructures.items.Variable;
import lupos.datastructures.items.literal.Literal;
import lupos.datastructures.queryresult.QueryResult;
import lupos.engine.operators.messages.BindingsFactoryMessage;
import lupos.engine.operators.messages.BoundVariablesMessage;
import lupos.engine.operators.messages.Message;
public class ReduceEnv extends SingleInputOperator {
private List<Variable> letThrough = new LinkedList<Variable>();
private final List<Variable> substitutionsVariableLeft = new LinkedList<Variable>();
private final List<Variable> substitutionsVariableRight = new LinkedList<Variable>();
private List<Variable> substitutionsLiteralLeft = new LinkedList<Variable>();
private List<Literal> substitutionsLiteralRight = new LinkedList<Literal>();
private List<Literal> filterLeft = new LinkedList<Literal>();
private final List<Variable> filterRight = new LinkedList<Variable>();
protected BindingsFactory bindingsFactory;
// Simulate
// private Item[] valueOrVariable;
@Override
public Message preProcessMessage(final BoundVariablesMessage msg) {
this.intersectionVariables = new HashSet<Variable>();
this.unionVariables = new HashSet<Variable>();
final BoundVariablesMessage result = new BoundVariablesMessage(msg);
for (final Variable i : this.substitutionsVariableLeft) {
result.getVariables().add(i);
this.intersectionVariables.add(i);
this.unionVariables.add(i);
}
for (final Variable i : this.substitutionsLiteralLeft) {
result.getVariables().add(i);
this.intersectionVariables.add(i);
this.unionVariables.add(i);
}
return result;
}
public ReduceEnv() {
}
/*
* public Variable getVariable(Item right){ Variable var = null;
* if(right.isVariable()){ int index =
* substitutionsVariableRight.indexOf(right); if(index!=-1){ var =
* substitutionsVariableLeft.get(index); } } else{ int index =
* substitutionsLiteralRight.indexOf(right); if(index!=-1){ var =
* substitutionsLiteralLeft.get(index); } } return var; }
*/
public List<Literal> getFilterLeft() {
return this.filterLeft;
}
public void setFilterLeft(final List<Literal> filterLeft) {
this.filterLeft = filterLeft;
}
public List<Variable> getSubstitutionsLiteralLeft() {
return this.substitutionsLiteralLeft;
}
public void setSubstitutionsLiteralLeft(
final List<Variable> substitutionsLiteralLeft) {
this.substitutionsLiteralLeft = substitutionsLiteralLeft;
}
public List<Literal> getSubstitutionsLiteralRight() {
return this.substitutionsLiteralRight;
}
public void setSubstitutionsLiteralRight(
final List<Literal> substitutionsLiteralRight) {
this.substitutionsLiteralRight = substitutionsLiteralRight;
}
public List<Variable> getLetThrough() {
return this.letThrough;
}
public void setLetThrough(final List<Variable> letThrough) {
this.letThrough = letThrough;
}
public List<Variable> getSubstitutionsVariableLeft() {
return this.substitutionsVariableLeft;
}
public List<Variable> getSubstitutionsVariableRight() {
return this.substitutionsVariableRight;
}
public void addSubstitution(final Variable variable, final Variable content) {
this.substitutionsVariableLeft.add(variable);
this.substitutionsVariableRight.add(content);
}
public void addSubstitution(final Variable variable, final Literal content) {
this.substitutionsLiteralLeft.add(variable);
this.substitutionsLiteralRight.add(content);
}
public void addFilter(final Literal content, final Variable variable) {
this.filterLeft.add(content);
this.filterRight.add(variable);
}
@Override
public Message preProcessMessage(final BindingsFactoryMessage msg){
this.bindingsFactory = msg.getBindingsFactory();
return msg;
}
@Override
public QueryResult process(final QueryResult oldBindings,
final int operandID) {
final QueryResult qr = QueryResult.createInstance();
for (final Bindings oldBinding : oldBindings) {
// Triple triple = getTriple();
final Bindings bindings = this.bindingsFactory.createInstance();
Literal literal = null;
for (int i = 0; i < this.filterLeft.size(); i++) {
// its value has to be equal to the corresponding value of
// the triple pattern
if (!this.filterLeft.get(i).getLiteral(null).valueEquals(
oldBinding.get(this.filterRight.get(i)))) {
return null;
}
}
// process all items
// for(int i = 0; i < 3; i++){
for (int i = 0; i < this.substitutionsLiteralLeft.size(); i++) {
// if the item is an unbound variable
final Variable item = this.substitutionsLiteralLeft.get(i);
if ((literal = bindings.get(item)) == null) {
bindings.add(item, this.substitutionsLiteralRight.get(i));
}
// if the item is a variable which is already bound
// and the value differs from the value of the triple
// which would be used as binding, a conflict was
// detected
else if (!literal.valueEquals(this.substitutionsLiteralRight.get(i))) {
return null; // join within triple pattern!
}
}
for (int i = 0; i < this.substitutionsVariableLeft.size(); i++) {
// if the item is an unbound variable
final Variable item = this.substitutionsVariableLeft.get(i);
if ((literal = bindings.get(item)) == null) {
bindings.add(item, oldBinding
.get(this.substitutionsVariableRight.get(i)));
}
// if the item is a variable which is already bound
// and the value differs from the value of the triple
// which would be used as binding, a conflict was
// detected
else if (!literal.valueEquals(oldBinding
.get(this.substitutionsVariableRight.get(i)))) {
return null; // join within triple pattern!
}
}
qr.add(bindings);
}
// bindings.addTriple(triple);
return qr;
}
/*
* private Bindings addAllLiteralSubstitutions(){ Bindings bnew =
* Bindings.createNewInstance(); //Process all literal substitutions for(int
* i=0; i<substitutionsLiteralLeft.size();i++){ Item left =
* substitutionsLiteralLeft.get(i); Literal right =
* substitutionsLiteralRight.get(i); if((!left.isVariable()) &&
* (!left.equals(right))){ return null; } //Add Tupel (left variable, right
* literal) else if(left.isVariable()){ bnew.add(left.toString(), right); }
* } return bnew; }
*/
@Override
public String toString() {
final String text = "Reduce to (" + this.substitutionsVariableLeft + ","
+ this.substitutionsVariableRight + ")";
// if(substitutionsLiteralLeft.size()>0) text +=
// "\n "+substitutionsLiteralLeft;
return text;
}
}