/**
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
*/
package com.bigdata.bop;
import java.util.Iterator;
import java.util.LinkedHashSet;
/**
* A factory which may be used when some identifiers need to be reserved.
*/
public class BOpIdFactory implements IdFactory {
/** The set of reserved bop identifiers. */
private LinkedHashSet<Integer> ids;
private int nextId = 0;
/**
* Reserve a bop id by adding it to a set of known identifiers that will not
* be issued by {@link #nextId()}.
*
* @param id
* The identifier.
*/
public void reserve(final int id) {
synchronized (this) {
if (ids == null) {
// Lazily allocated.
ids = new LinkedHashSet<Integer>();
ids.add(id);
}
}
}
@Override
public int nextId() {
synchronized (this) {
if (ids != null) {
while (ids.contains(nextId)) {
nextId++;
}
}
return nextId++;
}
}
/**
* Reserve ids used by the predicates in some join graph.
*
* @param preds
* The vertices of the join graph.
*/
public void reserveIds(final IPredicate<?>[] preds) {
if (preds == null)
throw new IllegalArgumentException();
for (IPredicate<?> p : preds) {
reserve(p.getId());
}
}
/**
* Reserve ids used by the constraints for some predicate or join graph.
*
* @param constraints
* The constraints that attach to some predicate (optional).
*/
public void reserveIds(final IConstraint[] constraints) {
if (constraints == null)
return;
for (IConstraint c : constraints) {
final Iterator<BOp> itr = BOpUtility
.preOrderIteratorWithAnnotations(c);
while (itr.hasNext()) {
final BOp y = itr.next();
final Integer anId = (Integer) y
.getProperty(BOp.Annotations.BOP_ID);
if (anId != null)
reserve(anId.intValue());
}
}
}
}