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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.data.input.impl;
import com.google.common.base.Function;
import com.google.common.base.Preconditions;
import com.google.common.base.Splitter;
import com.google.common.collect.Iterables;
import org.apache.druid.data.input.InputEntity;
import org.apache.druid.data.input.InputRow;
import org.apache.druid.data.input.InputRowSchema;
import org.apache.druid.data.input.TextReader;
import org.apache.druid.java.util.common.ISE;
import org.apache.druid.java.util.common.collect.Utils;
import org.apache.druid.java.util.common.parsers.ParseException;
import org.apache.druid.java.util.common.parsers.ParserUtils;
import org.apache.druid.java.util.common.parsers.Parsers;
import javax.annotation.Nullable;
import java.io.IOException;
import java.util.Collections;
import java.util.List;
import java.util.Map;
/**
* DelimitedValueReader is the reader for Delimitor Separate Value format input data(CSV/TSV).
*/
public class DelimitedValueReader extends TextReader
{
private final boolean findColumnsFromHeader;
private final int skipHeaderRows;
private final Function multiValueFunction;
private final DelimitedValueParser parser;
@Nullable
private List columns;
interface DelimitedValueParser
{
List parseLine(String line) throws IOException;
}
DelimitedValueReader(
InputRowSchema inputRowSchema,
InputEntity source,
@Nullable String listDelimiter,
@Nullable List columns,
boolean findColumnsFromHeader,
int skipHeaderRows,
DelimitedValueParser parser
)
{
super(inputRowSchema, source);
this.findColumnsFromHeader = findColumnsFromHeader;
this.skipHeaderRows = skipHeaderRows;
final String finalListDelimeter = listDelimiter == null ? Parsers.DEFAULT_LIST_DELIMITER : listDelimiter;
this.multiValueFunction = ParserUtils.getMultiValueFunction(finalListDelimeter, Splitter.on(finalListDelimeter));
this.columns = findColumnsFromHeader ? null : columns; // columns will be overriden by header row
this.parser = parser;
}
@Override
public List parseInputRows(String line) throws IOException, ParseException
{
final Map zipped = parseLine(line);
return Collections.singletonList(MapInputRowParser.parse(getInputRowSchema(), zipped));
}
@Override
public List