/*
* 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.value.decorator;
import java.util.Iterator;
import java.util.NoSuchElementException;
import org.optaplanner.core.api.domain.valuerange.ValueRangeProvider;
import org.optaplanner.core.impl.domain.variable.descriptor.GenuineVariableDescriptor;
import org.optaplanner.core.impl.heuristic.selector.common.iterator.SelectionIterator;
import org.optaplanner.core.impl.heuristic.selector.value.AbstractValueSelector;
import org.optaplanner.core.impl.heuristic.selector.value.EntityIndependentValueSelector;
import org.optaplanner.core.impl.heuristic.selector.value.ValueSelector;
public class SelectedCountLimitValueSelector extends AbstractValueSelector implements EntityIndependentValueSelector {
protected final ValueSelector childValueSelector;
protected final long selectedCountLimit;
/**
* Unlike most of the other {@link ValueSelector} decorations,
* this one works for an entity dependent {@link ValueSelector} too.
* @param childValueSelector never null, if any of the {@link EntityIndependentValueSelector} specific methods
* are going to be used, this parameter must also implement that interface
* @param selectedCountLimit at least 0
*/
public SelectedCountLimitValueSelector(ValueSelector childValueSelector, long selectedCountLimit) {
this.childValueSelector = childValueSelector;
this.selectedCountLimit = selectedCountLimit;
if (selectedCountLimit < 0L) {
throw new IllegalArgumentException("The selector (" + this
+ ") has a negative selectedCountLimit (" + selectedCountLimit + ").");
}
phaseLifecycleSupport.addEventListener(childValueSelector);
}
// ************************************************************************
// Worker methods
// ************************************************************************
@Override
public GenuineVariableDescriptor getVariableDescriptor() {
return childValueSelector.getVariableDescriptor();
}
@Override
public boolean isCountable() {
return true;
}
@Override
public boolean isNeverEnding() {
return false;
}
@Override
public long getSize(Object entity) {
long childSize = childValueSelector.getSize(entity);
return Math.min(selectedCountLimit, childSize);
}
@Override
public long getSize() {
if (!(childValueSelector instanceof EntityIndependentValueSelector)) {
throw new IllegalArgumentException("To use the method getSize(), the moveSelector (" + this
+ ") needs to be based on an EntityIndependentValueSelector (" + childValueSelector + ")."
+ " Check your @" + ValueRangeProvider.class.getSimpleName() + " annotations.");
}
long childSize = ((EntityIndependentValueSelector) childValueSelector).getSize();
return Math.min(selectedCountLimit, childSize);
}
@Override
public Iterator<Object> iterator(Object entity) {
return new SelectedCountLimitValueIterator(childValueSelector.iterator(entity));
}
@Override
public Iterator<Object> iterator() {
return new SelectedCountLimitValueIterator(((EntityIndependentValueSelector) childValueSelector).iterator());
}
@Override
public Iterator<Object> endingIterator(Object entity) {
return new SelectedCountLimitValueIterator(childValueSelector.endingIterator(entity));
}
private class SelectedCountLimitValueIterator extends SelectionIterator<Object> {
private final Iterator<Object> childValueIterator;
private long selectedSize;
public SelectedCountLimitValueIterator(Iterator<Object> childValueIterator) {
this.childValueIterator = childValueIterator;
selectedSize = 0L;
}
@Override
public boolean hasNext() {
return selectedSize < selectedCountLimit && childValueIterator.hasNext();
}
@Override
public Object next() {
if (selectedSize >= selectedCountLimit) {
throw new NoSuchElementException();
}
selectedSize++;
return childValueIterator.next();
}
}
@Override
public String toString() {
return "SelectedCountLimit(" + childValueSelector + ")";
}
}