/*
* Copyright (c) 2013 Data Harmonisation Panel
*
* All rights reserved. This program and the accompanying materials are made
* available under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation, either version 3 of the License,
* or (at your option) any later version.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this distribution. If not, see <http://www.gnu.org/licenses/>.
*
* Contributors:
* Data Harmonisation Panel <http://www.dhpanel.eu>
*/
package eu.esdihumboldt.hale.ui.service.instance.sample.internal.sampler.first;
import java.util.Map;
import com.google.common.base.Function;
import com.google.common.collect.Maps;
import eu.esdihumboldt.hale.common.instance.model.Filter;
import eu.esdihumboldt.hale.common.instance.model.Instance;
import eu.esdihumboldt.hale.common.instance.model.InstanceCollection;
import eu.esdihumboldt.hale.common.instance.model.ResourceIterator;
import eu.esdihumboldt.hale.common.instance.model.ext.helper.FullInstanceIteratorSupport;
import eu.esdihumboldt.hale.common.instance.model.ext.helper.InstanceCollectionDecorator;
import eu.esdihumboldt.hale.common.instance.model.impl.FilteredInstanceCollection;
import eu.esdihumboldt.hale.common.schema.model.TypeDefinition;
import gnu.trove.TObjectIntHashMap;
/**
* Simple implementation of an instance collection where only a specific number
* of instances per types is returned.
*
* @author Simon Templer
*/
public class FirstInstancesPerType extends InstanceCollectionDecorator {
/**
* Iterator that returns at maximum a specific number of instances per type.
*/
private class FirstSampleIterator extends FullInstanceIteratorSupport {
private final TObjectIntHashMap<TypeDefinition> typeCount = new TObjectIntHashMap<>();
/**
* Constructor.
*
* @param decoratee the decoratee
*/
public FirstSampleIterator(ResourceIterator<Instance> decoratee) {
super(decoratee);
}
@Override
public boolean hasNext() {
proceedToNextValid();
return super.hasNext();
}
private void proceedToNextValid() {
// skip all invalid instances where the limit has already been
// reached
while (super.hasNext() && typeCount.get(super.typePeek()) >= max) {
super.skip();
}
}
@Override
public Instance next() {
proceedToNextValid();
Instance result = super.next();
typeCount.adjustOrPutValue(result.getDefinition(), 1, 1);
return result;
}
@Override
public TypeDefinition typePeek() {
proceedToNextValid();
return super.typePeek();
}
@Override
public void skip() {
proceedToNextValid();
super.skip();
}
@Override
public boolean supportsTypePeek() {
return true;
}
}
private final int max;
/**
* Constructor.
*
* @param instances the original instance collection
* @param max the maximum number of instances per type
*/
public FirstInstancesPerType(InstanceCollection instances, int max) {
super(instances);
this.max = max;
}
@Override
public ResourceIterator<Instance> iterator() {
return new FirstSampleIterator(super.iterator());
}
@Override
public int size() {
return InstanceCollection.UNKNOWN_SIZE;
}
@Override
public boolean hasSize() {
return false;
}
@Override
public InstanceCollection select(Filter filter) {
// filter the samples
return FilteredInstanceCollection.applyFilter(this, filter);
}
@Override
public Map<TypeDefinition, InstanceCollection> fanout() {
Map<TypeDefinition, InstanceCollection> fanout = super.fanout();
if (fanout != null) {
// individually sample each instance collection
return Maps.transformValues(fanout,
new Function<InstanceCollection, InstanceCollection>() {
@Override
public InstanceCollection apply(InstanceCollection org) {
return new FirstOverallInstances(org, max);
}
});
}
return null;
}
}