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A module that is everything required to understands Druid Segments
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.apache.druid.segment.join.table;
import it.unimi.dsi.fastutil.ints.IntSortedSet;
import it.unimi.dsi.fastutil.ints.IntSortedSets;
import org.apache.druid.segment.DimensionHandlerUtils;
import org.apache.druid.segment.column.ColumnType;
import javax.annotation.Nullable;
/**
* An {@link IndexedTable.Index} backed by an int array.
*
* This is for nonnull long-typed keys whose values all fall in a "reasonable" range. Built by
* {@link RowBasedIndexBuilder#build()} when these conditions are met.
*/
public class UniqueLongArrayIndex implements IndexedTable.Index
{
/**
* Array index is the key, value is the row number.
*/
private final int[] index;
private final long minKey;
/**
* Create a new instance backed by a given array.
*
* @param index an int array where position {@code i} corresponds to the key {@code i + minKey}
* @param minKey lowest-valued key
*
* @see RowBasedIndexBuilder#build() the main caller
*/
UniqueLongArrayIndex(int[] index, long minKey)
{
this.index = index;
this.minKey = minKey;
}
@Override
public ColumnType keyType()
{
return ColumnType.LONG;
}
@Override
public boolean areKeysUnique(final boolean includeNull)
{
return true;
}
@Override
public IntSortedSet find(@Nullable Object key)
{
if (key == null) {
// This index class never contains null keys.
return IntSortedSets.EMPTY_SET;
}
final Long longKey = DimensionHandlerUtils.convertObjectToLong(key);
if (longKey != null) {
final int row = findUniqueLong(longKey);
if (row >= 0) {
return IntSortedSets.singleton(row);
}
}
return IntSortedSets.EMPTY_SET;
}
@Override
public int findUniqueLong(long key)
{
if (key >= minKey && key < (minKey + index.length)) {
return index[(int) (key - minKey)];
} else {
return NOT_FOUND;
}
}
}