/**
* 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.distributed.storage.distributionstrategy.tripleproperties;
import lupos.datastructures.items.Item;
import lupos.datastructures.items.Triple;
import lupos.datastructures.items.literal.Literal;
import lupos.distributed.storage.distributionstrategy.TriplePatternNotSupportedError;
import lupos.engine.operators.tripleoperator.TriplePattern;
/**
* This class implements the distribution strategy, where the
* triples are distributed according to one and two keys distribution strategies as well as
* to the subject - predicate - object
* (to seven different nodes).
*/
public class OneToThreeKeysDistribution implements IDistributionKeyContainer<String> {
// just for avoiding redundant code...
private final OneKeyDistribution oneKeyDistribution = new OneKeyDistribution();
private final TwoKeysDistribution twoKeysDistribution = new TwoKeysDistribution();
protected final static String TYPE_SPO = "SPO";
@Override
public KeyContainer<String>[] getKeysForStoring(final Triple triple) {
@SuppressWarnings("unchecked")
final KeyContainer<String>[] keys = new KeyContainer[7];
System.arraycopy(this.oneKeyDistribution.getKeysForStoring(triple), 0, keys, 0, 3);
System.arraycopy(this.twoKeysDistribution.getKeysForStoring(triple), 0, keys, 3, 3);
keys[6] = new KeyContainer<String>(TYPE_SPO,
triple.getSubject().originalString() +
triple.getPredicate().originalString() +
triple.getObject().originalString());
return keys;
}
@SuppressWarnings("unchecked")
@Override
public KeyContainer<String>[] getKeysForQuerying(final TriplePattern triplePattern) throws TriplePatternNotSupportedError {
int numberOfLiterals = 0;
// count the number of literals in a triple pattern...
for(final Item item: triplePattern){
if(!item.isVariable()){
numberOfLiterals++;
}
}
switch(numberOfLiterals){
case 1:
return this.oneKeyDistribution.getKeysForQuerying(triplePattern);
case 2:
return this.twoKeysDistribution.getKeysForQuerying(triplePattern);
case 3:
return new KeyContainer[]{ new KeyContainer<String>(TYPE_SPO, ((Literal)triplePattern.getSubject()).originalString() + ((Literal)triplePattern.getPredicate()).originalString() + ((Literal)triplePattern.getObject()).originalString()) };
default:
throw new TriplePatternNotSupportedError(this, triplePattern);
}
}
@Override
public String toString(){
return "One to three keys distribution strategy (triple (s, p, o) has keys { 'S' + s, 'P' + p, 'O' + o, 'SP' + s + p, 'PO' + p + o, 'SO' + s + o, 'SPO' + s + p + o })";
}
@Override
public String[] getKeyTypes() {
return OneToThreeKeysDistribution.getPossibleKeyTypes();
}
public static String[] getPossibleKeyTypes(){
return new String[]{ OneKeyDistribution.TYPE_S, OneKeyDistribution.TYPE_P,OneKeyDistribution.TYPE_O,
TwoKeysDistribution.TYPE_SP, TwoKeysDistribution.TYPE_SO, TwoKeysDistribution.TYPE_PO,
TYPE_SPO };
}
}