org.apache.druid.query.rowsandcols.concrete.ColumnBasedFrameRowsAndColumns Maven / Gradle / Ivy
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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.query.rowsandcols.concrete;
import org.apache.druid.frame.Frame;
import org.apache.druid.frame.FrameType;
import org.apache.druid.frame.read.FrameReader;
import org.apache.druid.frame.read.columnar.FrameColumnReaders;
import org.apache.druid.frame.segment.FrameStorageAdapter;
import org.apache.druid.java.util.common.ISE;
import org.apache.druid.java.util.common.Intervals;
import org.apache.druid.query.rowsandcols.RowsAndColumns;
import org.apache.druid.query.rowsandcols.column.Column;
import org.apache.druid.query.rowsandcols.semantic.WireTransferable;
import org.apache.druid.segment.CloseableShapeshifter;
import org.apache.druid.segment.StorageAdapter;
import org.apache.druid.segment.column.ColumnType;
import org.apache.druid.segment.column.RowSignature;
import javax.annotation.Nullable;
import java.util.Collection;
import java.util.LinkedHashMap;
public class ColumnBasedFrameRowsAndColumns implements RowsAndColumns, AutoCloseable, CloseableShapeshifter
{
private final Frame frame;
private final RowSignature signature;
private final LinkedHashMap colCache = new LinkedHashMap<>();
public ColumnBasedFrameRowsAndColumns(Frame frame, RowSignature signature)
{
this.frame = FrameType.COLUMNAR.ensureType(frame);
this.signature = signature;
}
@Override
public Collection getColumnNames()
{
return signature.getColumnNames();
}
@Override
public int numRows()
{
return frame.numRows();
}
@Nullable
@Override
public Column findColumn(String name)
{
// Use contains so that we can negative cache.
if (!colCache.containsKey(name)) {
final int columnIndex = signature.indexOf(name);
if (columnIndex < 0) {
colCache.put(name, null);
} else {
final ColumnType columnType = signature
.getColumnType(columnIndex)
.orElseThrow(() -> new ISE("just got the id, why is columnType not there?"));
colCache.put(name, FrameColumnReaders.create(name, columnIndex, columnType).readRACColumn(frame));
}
}
return colCache.get(name);
}
@SuppressWarnings("unchecked")
@Nullable
@Override
public T as(Class clazz)
{
if (StorageAdapter.class.equals(clazz)) {
return (T) new FrameStorageAdapter(frame, FrameReader.create(signature), Intervals.ETERNITY);
}
if (WireTransferable.class.equals(clazz)) {
return (T) this;
}
return null;
}
@Override
public void close()
{
// nothing to close
}
}