/*
Copyright (C) SYSTAP, LLC DBA Blazegraph 2006-2016. All rights reserved.
Contact:
SYSTAP, LLC DBA Blazegraph
2501 Calvert ST NW #106
Washington, DC 20008
licenses@blazegraph.com
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/*
* Created on Aug 18, 2008
*/
package com.bigdata.bop.joinGraph;
import java.util.Arrays;
import com.bigdata.relation.rule.IRule;
import com.bigdata.relation.rule.eval.IJoinNexus;
/**
* A factory for {@link IEvaluationPlan}s that uses a caller specified
* evaluation order.
*
* @author <a href="mailto:thompsonbry@users.sourceforge.net">Bryan Thompson</a>
* @version $Id$
*/
public class FixedEvaluationPlanFactory implements IEvaluationPlanFactory {
/**
*
*/
private static final long serialVersionUID = 4374802847795489346L;
/** the evaluation order as specified to the ctor. */
private final int[] order;
public FixedEvaluationPlanFactory(final int[] order) {
if (order == null)
throw new IllegalArgumentException();
/*
* verify that the evaluation order uses each predicate in the tail of
* the rule exactly once (e.g., it is a permutation of the sequence
* [0,1,2...,tailCount-1].
*/
for (int i = 0; i < order.length; i++) {
int nfound = 0;
for (int j = 0; j < order.length; j++) {
if (order[j] == i)
nfound++;
}
if (nfound == 0)
throw new IllegalArgumentException("tailIndex=" + i
+ " is not in the evaluation order: "
+ Arrays.toString(order));
if (nfound > 1)
throw new IllegalArgumentException("tailIndex=" + i
+ " occurs more than once in the evaluation order: "
+ Arrays.toString(order));
}
this.order = order;
}
public IEvaluationPlan newPlan(final IJoinNexus joinNexus, final IRule rule) {
final int tailCount = rule.getTailCount();
if (order.length != tailCount) {
throw new IllegalArgumentException("tailCount=" + tailCount
+ ", but have order[] of length=" + order.length);
}
return new IEvaluationPlan() {
public int[] getOrder() {
return order;
}
public boolean isEmpty() {
return false;
}
public long rangeCount(int tailIndex) {
return joinNexus.getRangeCountFactory().rangeCount(
rule.getTail(tailIndex));
}
public String toString() {
return "order="+Arrays.toString(order);
}
};
}
}