/**
* 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.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 the subject, predicate and object
* (to three different nodes).
*/
public class OneKeyDistribution implements IDistributionKeyContainer<String> {
protected final static String TYPE_S = "S";
protected final static String TYPE_P = "P";
protected final static String TYPE_O = "O";
@SuppressWarnings("unchecked")
@Override
public KeyContainer<String>[] getKeysForStoring(final Triple triple) {
return new KeyContainer[]{
new KeyContainer<String>(TYPE_S, triple.getSubject().originalString()),
new KeyContainer<String>(TYPE_P, triple.getPredicate().originalString()),
new KeyContainer<String>(TYPE_O, triple.getObject().originalString())
};
}
@SuppressWarnings("unchecked")
@Override
public KeyContainer<String>[] getKeysForQuerying(final TriplePattern triplePattern) throws TriplePatternNotSupportedError {
if(triplePattern.getSubject().isVariable()){
if(triplePattern.getObject().isVariable()){
if(triplePattern.getPredicate().isVariable()){
// only variables in the triple pattern is not supported!
throw new TriplePatternNotSupportedError(this, triplePattern);
} else {
return new KeyContainer[]{ new KeyContainer<String>(TYPE_P, ((Literal)triplePattern.getPredicate()).originalString()) };
}
} else {
return new KeyContainer[]{ new KeyContainer<String>(TYPE_O, ((Literal)triplePattern.getObject()).originalString()) };
}
} else {
return new KeyContainer[]{ new KeyContainer<String>(TYPE_S, ((Literal)triplePattern.getSubject()).originalString()) };
}
}
@Override
public String toString(){
return "One key distribution strategy (triple (s, p, o) has keys { 'S' + s, 'P' + p, 'O' + o })";
}
@Override
public String[] getKeyTypes() {
return OneKeyDistribution.getPossibleKeyTypes();
}
public static String[] getPossibleKeyTypes(){
return new String[] {TYPE_S, TYPE_P, TYPE_O};
}
}