org.apache.flink.table.sources.orc.OrcUtils Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one
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* 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,
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*/
package org.apache.flink.table.sources.orc;
import org.apache.orc.Reader;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
/**
* Utils for Orc connector.
*/
public class OrcUtils {
public static int[] requestedColumnIds(
boolean isCaseSensitive,
String[] requiredFieldNames,
String[] schemaFieldNames,
Reader reader) {
String[] orcFieldNames = reader.getSchema().getFieldNames().toArray(new String[0]);
if (orcFieldNames.length == 0) {
// Some old empty ORC files always have an empty schema stored in their footer.
return null;
} else {
boolean isHiveOrcFile = Arrays.stream(orcFieldNames).allMatch(field -> field.startsWith("_col"));
List ret = new ArrayList<>();
if (isHiveOrcFile) {
// This is a ORC file written by Hive.
// assume the required field names are the physical field names.
for (String field : requiredFieldNames) {
int index = fieldIndex(field, schemaFieldNames, isCaseSensitive);
ret.add(index);
}
} else {
for (String field : requiredFieldNames) {
int index = fieldIndex(field, orcFieldNames, isCaseSensitive);
ret.add(index);
}
}
return ret.stream().mapToInt(i -> i).toArray();
}
}
// TODO: performance issue?
private static int fieldIndex(String field, String[] fieldNames, boolean isCaseSensitive) {
for (int i = 0; i < fieldNames.length; i++) {
if ((isCaseSensitive && field.equals(fieldNames[i]))
|| (!isCaseSensitive && field.equalsIgnoreCase(fieldNames[i]))) {
return i;
}
}
return -1;
}
}