/**
* 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.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.LinkedList;
import lupos.datastructures.bindings.Bindings;
import lupos.datastructures.bindings.BindingsFactory;
import lupos.datastructures.items.Item;
import lupos.datastructures.items.Variable;
import lupos.datastructures.queryresult.QueryResult;
import lupos.engine.operators.BasicOperator;
import lupos.engine.operators.messages.BindingsFactoryMessage;
import lupos.engine.operators.messages.BoundVariablesMessage;
import lupos.engine.operators.messages.Message;
public class ReplaceVar extends SingleInputOperator {
private LinkedList<Variable> substitutionsVariableLeft = new LinkedList<Variable>();
private LinkedList<Variable> substitutionsVariableRight = new LinkedList<Variable>();
protected BindingsFactory bindingsFactory;
public Variable getReplacement(final Variable v) {
for (int i = 0; i < this.substitutionsVariableLeft.size(); i++) {
if (this.substitutionsVariableRight.get(i).equals(v)) {
return this.substitutionsVariableLeft.get(i);
}
}
return null;
}
public void removeSubstitution(final Variable left, final Variable right) {
final LinkedList<Integer> pos = this.getPositions(this.substitutionsVariableLeft,
left);
int index;
for (int i = 0; i < pos.size(); i++) {
index = pos.get(i);
if (this.substitutionsVariableRight.get(index).equals(right)) {
this.substitutionsVariableLeft.remove(index);
this.substitutionsVariableRight.remove(index);
break;
}
}
}
public void setSubstitutionsVariableLeft(
final LinkedList<Variable> substitutionsVariableLeft) {
this.substitutionsVariableLeft = substitutionsVariableLeft;
}
public void setSubstitutionsVariableRight(
final LinkedList<Variable> substitutionsVariableRight) {
this.substitutionsVariableRight = substitutionsVariableRight;
}
public LinkedList<Variable> getSubstitutionsVariableLeft() {
return this.substitutionsVariableLeft;
}
public LinkedList<Variable> getSubstitutionsVariableRight() {
return this.substitutionsVariableRight;
}
@Override
public Message preProcessMessage(final BoundVariablesMessage msg) {
this.intersectionVariables = new LinkedList<Variable>();
this.intersectionVariables.addAll(this.substitutionsVariableLeft);
this.unionVariables = this.intersectionVariables;
msg.getVariables().clear();
msg.getVariables().addAll(this.intersectionVariables);
return msg;
}
private LinkedList<Integer> getPositions(final LinkedList<Variable> list,
final Item item) {
final LinkedList<Integer> pos = new LinkedList<Integer>();
for (int i = 0; i < list.size(); i++) {
if (list.get(i).equals(item)) {
pos.add(i);
}
}
return pos;
}
private boolean contains(final Item left, final Item right) {
final LinkedList<Integer> indices = this.getPositions(
this.substitutionsVariableLeft, left);
if (indices.size() != 0) {
for (int i = 0; i < indices.size(); i++) {
if (this.substitutionsVariableRight.get(indices.get(i))
.equals(right)) {
return true;
}
}
}
return false;
}
public void addSubstitution(final Variable variable, final Variable content) {
if (!this.contains(variable, content)) {
this.substitutionsVariableLeft.add(variable);
this.substitutionsVariableRight.add(content);
}
}
public void removeSubstitutionVars(final int index) {
this.substitutionsVariableLeft.remove(index);
this.substitutionsVariableRight.remove(index);
}
@Override
public Message preProcessMessage(final BindingsFactoryMessage msg){
this.bindingsFactory = msg.getBindingsFactory();
return msg;
}
@Override
public QueryResult process(final QueryResult oldBindings,
final int operandID) {
return QueryResult.createInstance(new Iterator<Bindings>() {
Iterator<Bindings> oldIt = oldBindings.oneTimeIterator();
@Override
public boolean hasNext() {
return this.oldIt.hasNext();
}
@Override
public Bindings next() {
if (!this.hasNext()) {
return null;
}
final Bindings oldBinding = this.oldIt.next();
if (oldBindings == null) {
return null;
}
final Bindings newBinding = ReplaceVar.this.bindingsFactory.createInstance();
for (int i = 0; i < ReplaceVar.this.substitutionsVariableLeft.size(); i++) {
final Variable itemName = ReplaceVar.this.substitutionsVariableLeft.get(i);
// always do like this!
newBinding.add(itemName, oldBinding
.get(ReplaceVar.this.substitutionsVariableRight.get(i)));
}
return newBinding;
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
});
}
@Override
public void cloneFrom(final BasicOperator bo) {
super.cloneFrom(bo);
if (bo instanceof ReplaceVar) {
final ReplaceVar rv = (ReplaceVar) bo;
this.substitutionsVariableLeft = (LinkedList<Variable>) rv.substitutionsVariableLeft
.clone();
this.substitutionsVariableRight = (LinkedList<Variable>) rv.substitutionsVariableRight
.clone();
}
}
@Override
public String toString() {
String result = super.toString() + "(";
for (int i = 0; i < this.substitutionsVariableLeft.size(); i++) {
if (i > 0) {
result += ", ";
}
result += this.substitutionsVariableLeft.get(i) + "="
+ this.substitutionsVariableRight.get(i);
}
return result + ")";
}
@Override
public boolean remainsSortedData(final Collection<Variable> sortCriterium){
return true;
}
@Override
public Collection<Variable> transformSortCriterium(final Collection<Variable> sortCriterium){
for (final Variable var : new ArrayList<Variable>(sortCriterium)) {
if (this.getSubstitutionsVariableRight().contains(var)) {
sortCriterium.remove(var);
sortCriterium.add(this.getSubstitutionsVariableLeft().get(this.getSubstitutionsVariableRight().indexOf(var)));
}
}
return sortCriterium;
}
}