package de.lmu.ifi.dbs.elki.result;
/*
This file is part of ELKI:
Environment for Developing KDD-Applications Supported by Index-Structures
Copyright (C) 2012
Ludwig-Maximilians-Universität München
Lehr- und Forschungseinheit für Datenbanksysteme
ELKI Development Team
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
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 Affero General Public License for more details.
You should have received a copy of the GNU Affero General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
import java.util.Comparator;
import de.lmu.ifi.dbs.elki.database.datastore.DataStore;
import de.lmu.ifi.dbs.elki.database.ids.ArrayModifiableDBIDs;
import de.lmu.ifi.dbs.elki.database.ids.DBID;
import de.lmu.ifi.dbs.elki.database.ids.DBIDUtil;
import de.lmu.ifi.dbs.elki.database.ids.DBIDs;
import de.lmu.ifi.dbs.elki.utilities.iterator.IterableIterator;
import de.lmu.ifi.dbs.elki.utilities.iterator.IterableUtil;
/**
* Result class providing an ordering backed by a hashmap.
*
* @author Erich Schubert
*
* @param <T> Data type in hash map
*/
public class OrderingFromDataStore<T extends Comparable<T>> extends BasicResult implements OrderingResult {
/**
* HashMap with object values
*/
protected DataStore<? extends T> map;
/**
* Database IDs
*/
protected DBIDs ids;
/**
* Comparator to use when sorting
*/
protected Comparator<T> comparator;
/**
* Factor for ascending (+1) and descending (-1) ordering.
*/
int ascending;
/**
* Constructor with comparator
*
* @param name The long name (for pretty printing)
* @param shortname the short name (for filenames etc.)
* @param ids DBIDs included
* @param map data hash map
* @param comparator comparator to use, may be null
* @param descending ascending (false) or descending (true) order.
*/
public OrderingFromDataStore(String name, String shortname, DBIDs ids, DataStore<? extends T> map, Comparator<T> comparator, boolean descending) {
super(name, shortname);
this.map = map;
this.ids = ids;
this.comparator = comparator;
this.ascending = descending ? -1 : 1;
}
/**
* Constructor without comparator
*
* @param name The long name (for pretty printing)
* @param shortname the short name (for filenames etc.)
* @param ids DBIDs included
* @param map data hash map
* @param descending ascending (false) or descending (true) order.
*/
public OrderingFromDataStore(String name, String shortname, DBIDs ids, DataStore<? extends T> map, boolean descending) {
super(name, shortname);
this.map = map;
this.ids = ids;
this.comparator = null;
this.ascending = descending ? -1 : 1;
}
/**
* Minimal Constructor
*
* @param name The long name (for pretty printing)
* @param shortname the short name (for filenames etc.)
* @param ids DBIDs included
* @param map data hash map
*/
public OrderingFromDataStore(String name, String shortname, DBIDs ids, DataStore<? extends T> map) {
super(name, shortname);
this.map = map;
this.ids = ids;
this.comparator = null;
this.ascending = 1;
}
@Override
public DBIDs getDBIDs() {
return ids;
}
@Override
public IterableIterator<DBID> iter(DBIDs ids) {
ArrayModifiableDBIDs sorted = DBIDUtil.newArray(ids);
if(comparator != null) {
sorted.sort(new DerivedComparator());
}
else {
sorted.sort(new ImpliedComparator());
}
return IterableUtil.fromIterable(sorted);
}
/**
* Internal comparator, accessing the map to sort objects
*
* @author Erich Schubert
*
* @apiviz.exclude
*/
protected final class ImpliedComparator implements Comparator<DBID> {
@Override
public int compare(DBID id1, DBID id2) {
T k1 = map.get(id1);
T k2 = map.get(id2);
assert (k1 != null);
assert (k2 != null);
return ascending * k1.compareTo(k2);
}
}
/**
* Internal comparator, accessing the map but then using the provided
* comparator to sort objects
*
* @author Erich Schubert
*
* @apiviz.exclude
*/
protected final class DerivedComparator implements Comparator<DBID> {
@Override
public int compare(DBID id1, DBID id2) {
T k1 = map.get(id1);
T k2 = map.get(id2);
assert (k1 != null);
assert (k2 != null);
return ascending * comparator.compare(k1, k2);
}
}
}