/*
* Copyright 2014 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.heuristic.selector.entity.decorator;
import java.util.Iterator;
import java.util.ListIterator;
import java.util.NoSuchElementException;
import org.optaplanner.core.impl.domain.entity.descriptor.EntityDescriptor;
import org.optaplanner.core.impl.heuristic.selector.common.iterator.SelectionIterator;
import org.optaplanner.core.impl.heuristic.selector.entity.AbstractEntitySelector;
import org.optaplanner.core.impl.heuristic.selector.entity.EntitySelector;
public class SelectedCountLimitEntitySelector extends AbstractEntitySelector {
protected final EntitySelector childEntitySelector;
protected final boolean randomSelection;
protected final long selectedCountLimit;
public SelectedCountLimitEntitySelector(EntitySelector childEntitySelector, boolean randomSelection,
long selectedCountLimit) {
this.childEntitySelector = childEntitySelector;
this.randomSelection = randomSelection;
this.selectedCountLimit = selectedCountLimit;
if (selectedCountLimit < 0L) {
throw new IllegalArgumentException("The selector (" + this
+ ") has a negative selectedCountLimit (" + selectedCountLimit + ").");
}
phaseLifecycleSupport.addEventListener(childEntitySelector);
}
// ************************************************************************
// Worker methods
// ************************************************************************
@Override
public EntityDescriptor getEntityDescriptor() {
return childEntitySelector.getEntityDescriptor();
}
@Override
public boolean isCountable() {
return true;
}
@Override
public boolean isNeverEnding() {
return false;
}
@Override
public long getSize() {
long childSize = childEntitySelector.getSize();
return Math.min(selectedCountLimit, childSize);
}
@Override
public Iterator<Object> iterator() {
return new SelectedCountLimitEntityIterator(childEntitySelector.iterator());
}
@Override
public ListIterator<Object> listIterator() {
// TODO Not yet implemented
throw new UnsupportedOperationException();
}
@Override
public ListIterator<Object> listIterator(int index) {
// TODO Not yet implemented
throw new UnsupportedOperationException();
}
@Override
public Iterator<Object> endingIterator() {
if (randomSelection) {
// With random selection, the first n elements can differ between iterator calls,
// so it's illegal to only return the first n elements in original order (that breaks NearbySelection)
return childEntitySelector.endingIterator();
} else {
return new SelectedCountLimitEntityIterator(childEntitySelector.endingIterator());
}
}
private class SelectedCountLimitEntityIterator extends SelectionIterator<Object> {
private final Iterator<Object> childEntityIterator;
private long selectedSize;
public SelectedCountLimitEntityIterator(Iterator<Object> childEntityIterator) {
this.childEntityIterator = childEntityIterator;
selectedSize = 0L;
}
@Override
public boolean hasNext() {
return selectedSize < selectedCountLimit && childEntityIterator.hasNext();
}
@Override
public Object next() {
if (selectedSize >= selectedCountLimit) {
throw new NoSuchElementException();
}
selectedSize++;
return childEntityIterator.next();
}
}
@Override
public String toString() {
return "SelectedCountLimit(" + childEntitySelector + ")";
}
}