tech.tablesaw.index.ShortIndex Maven / Gradle / Ivy
/*
* 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 tech.tablesaw.index;
import com.google.common.base.Preconditions;
import it.unimi.dsi.fastutil.ints.IntArrayList;
import it.unimi.dsi.fastutil.shorts.Short2ObjectAVLTreeMap;
import it.unimi.dsi.fastutil.shorts.Short2ObjectOpenHashMap;
import it.unimi.dsi.fastutil.shorts.Short2ObjectSortedMap;
import tech.tablesaw.api.ShortColumn;
import tech.tablesaw.columns.numbers.ShortColumnType;
import tech.tablesaw.selection.BitmapBackedSelection;
import tech.tablesaw.selection.Selection;
/**
* An index for four-byte integer and integer backed columns (date, category, time)
*/
public class ShortIndex implements Index {
private final Short2ObjectAVLTreeMap index;
public ShortIndex(ShortColumn column) {
Preconditions.checkArgument(column.type().equals(ShortColumnType.instance()),
"Short indexing only allowed on SHORT numeric columns");
int sizeEstimate = Integer.min(1_000_000, column.size() / 100);
Short2ObjectOpenHashMap tempMap = new Short2ObjectOpenHashMap<>(sizeEstimate);
for (int i = 0; i < column.size(); i++) {
short value = column.getShort(i);
IntArrayList recordIds = tempMap.get(value);
if (recordIds == null) {
recordIds = new IntArrayList();
recordIds.add(i);
tempMap.trim();
tempMap.put(value, recordIds);
} else {
recordIds.add(i);
}
}
index = new Short2ObjectAVLTreeMap<>(tempMap);
}
private static void addAllToSelection(IntArrayList tableKeys, Selection selection) {
for (int i : tableKeys) {
selection.add(i);
}
}
/**
* Returns a bitmap containing row numbers of all cells matching the given int
*
* @param value This is a 'key' from the index perspective, meaning it is a value from the standpoint of the column
*/
public Selection get(short value) {
Selection selection = new BitmapBackedSelection();
IntArrayList list = index.get(value);
if (list != null) {
addAllToSelection(list, selection);
}
return selection;
}
public Selection atLeast(short value) {
Selection selection = new BitmapBackedSelection();
Short2ObjectSortedMap tail = index.tailMap(value);
for (IntArrayList keys : tail.values()) {
addAllToSelection(keys, selection);
}
return selection;
}
public Selection greaterThan(short value) {
Selection selection = new BitmapBackedSelection();
Short2ObjectSortedMap tail = index.tailMap((short) (value + 1));
for (IntArrayList keys : tail.values()) {
addAllToSelection(keys, selection);
}
return selection;
}
public Selection atMost(short value) {
Selection selection = new BitmapBackedSelection();
Short2ObjectSortedMap head = index.headMap((short) (value + 1)); // we add 1 to get values equal to the arg
for (IntArrayList keys : head.values()) {
addAllToSelection(keys, selection);
}
return selection;
}
public Selection lessThan(short value) {
Selection selection = new BitmapBackedSelection();
Short2ObjectSortedMap head = index.headMap(value); // we add 1 to get values equal to the arg
for (IntArrayList keys : head.values()) {
addAllToSelection(keys, selection);
}
return selection;
}
}