/*
* Copyright 2015 Red Hat, Inc. and/or its affiliates.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.optaplanner.core.impl.constructionheuristic.placer;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import org.optaplanner.core.impl.heuristic.move.Move;
import org.optaplanner.core.impl.heuristic.selector.common.iterator.UpcomingSelectionIterator;
import org.optaplanner.core.impl.heuristic.selector.entity.EntitySelector;
import org.optaplanner.core.impl.heuristic.selector.move.MoveSelector;
public class QueuedEntityPlacer extends AbstractEntityPlacer implements EntityPlacer {
protected final EntitySelector entitySelector;
protected final List<MoveSelector> moveSelectorList;
public QueuedEntityPlacer(EntitySelector entitySelector, List<MoveSelector> moveSelectorList) {
this.entitySelector = entitySelector;
this.moveSelectorList = moveSelectorList;
phaseLifecycleSupport.addEventListener(entitySelector);
for (MoveSelector moveSelector : moveSelectorList) {
phaseLifecycleSupport.addEventListener(moveSelector);
}
}
@Override
public Iterator<Placement> iterator() {
return new QueuedEntityPlacingIterator(entitySelector.iterator());
}
private class QueuedEntityPlacingIterator extends UpcomingSelectionIterator<Placement> {
private final Iterator<Object> entityIterator;
private Iterator<MoveSelector> moveSelectorIterator;
private QueuedEntityPlacingIterator(Iterator<Object> entityIterator) {
this.entityIterator = entityIterator;
moveSelectorIterator = Collections.emptyIterator();
}
@Override
protected Placement createUpcomingSelection() {
Iterator<Move> moveIterator = null;
// Skip empty placements to avoid no-operation steps
while (moveIterator == null || !moveIterator.hasNext()) {
// If a moveSelector's iterator is empty, it might not be empty the next time
// (because the entity changes)
while (!moveSelectorIterator.hasNext()) {
if (!entityIterator.hasNext()) {
return noUpcomingSelection();
}
entityIterator.next();
moveSelectorIterator = moveSelectorList.iterator();
}
MoveSelector moveSelector = moveSelectorIterator.next();
moveIterator = moveSelector.iterator();
}
return new Placement(moveIterator);
}
}
}