[GitHub] [drill] paul-rogers commented on a change in pull request #1749: DRILL-7177: Format Plugin for Excel Files

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paul-rogers commented on a change in pull request #1749: DRILL-7177: Format Plugin for Excel Files
URL: https://github.com/apache/drill/pull/1749#discussion_r334292313
 
 

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 File path: contrib/format-excel/src/main/java/org/apache/drill/exec/store/excel/ExcelBatchReader.java
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+/*
+ * 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.drill.exec.store.excel;
+
+import org.apache.drill.common.exceptions.UserException;
+import org.apache.drill.common.types.TypeProtos;
+import org.apache.drill.exec.physical.impl.scan.file.FileScanFramework;
+import org.apache.drill.exec.physical.impl.scan.framework.ManagedReader;
+import org.apache.drill.exec.physical.resultSet.ResultSetLoader;
+import org.apache.drill.exec.physical.resultSet.RowSetLoader;
+import org.apache.drill.exec.record.metadata.ColumnMetadata;
+import org.apache.drill.exec.record.metadata.MetadataUtils;
+import org.apache.drill.exec.record.metadata.SchemaBuilder;
+import org.apache.drill.exec.record.metadata.TupleMetadata;
+import org.apache.drill.exec.vector.accessor.ScalarWriter;
+import org.apache.drill.exec.vector.accessor.TupleWriter;
+import org.apache.hadoop.fs.FSDataInputStream;
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.mapred.FileSplit;
+
+import org.apache.poi.ss.usermodel.Cell;
+import org.apache.poi.ss.usermodel.CellValue;
+import org.apache.poi.ss.usermodel.DateUtil;
+import org.apache.poi.ss.usermodel.FormulaEvaluator;
+import org.apache.poi.ss.usermodel.Row;
+import org.apache.poi.xssf.usermodel.XSSFSheet;
+import org.apache.poi.xssf.usermodel.XSSFWorkbook;
+import org.apache.drill.exec.physical.impl.scan.file.FileScanFramework.FileSchemaNegotiator;
+import org.joda.time.Instant;
+
+import java.util.Iterator;
+import java.io.IOException;
+import java.util.ArrayList;
+
+public class ExcelBatchReader implements ManagedReader<FileSchemaNegotiator> {
+  private ExcelReaderConfig readerConfig;
+
+  private static final org.slf4j.Logger logger = org.slf4j.LoggerFactory.getLogger(ExcelBatchReader.class);
+
+  private XSSFWorkbook workbook;
+
+  private FSDataInputStream fsStream;
+
+  private static final String SAFE_WILDCARD = "_$";
+
+  private static final String SAFE_SEPARATOR = "_";
+
+  private static final String PARSER_WILDCARD = ".*";
+
+  private static final String MISSING_FIELD_NAME_HEADER = "field_";
+
+  private static final String SAFE_NEWLINE_REPLACEMENT = " ";
+
+  private XSSFSheet sheet;
+
+  private FormulaEvaluator evaluator;
+
+  private ArrayList<String> excelFieldNames;
+
+  private Iterator<Row> rowIterator;
+
+  private int totalColumnCount;
+
+  private int lineCount;
+
+  private FileSplit split;
+
+  private ResultSetLoader loader;
+
+  private int recordCount;
+
+  public static class ExcelReaderConfig {
+    protected final ExcelFormatPlugin plugin;
+
+    protected int headerRow;
+
+    protected int lastRow;
+
+    protected int firstColumn;
+
+    protected int lastColumn;
+
+    protected boolean readAllFieldsAsVarChar;
+
+    protected boolean evaluateFormulae;
+
+    protected TupleMetadata schema;
+
+    protected String sheetName;
+
+    public ExcelReaderConfig(ExcelFormatPlugin plugin, int headerRow, int lastRow, int firstColumn, int lastColumn, boolean readAllFieldsAsVarChar, boolean evaluateFormulae,
+                             //TupleMetadata schema,
+                             String sheetName) {
+      this.plugin = plugin;
+      this.headerRow = headerRow;
+      this.lastRow = lastRow;
+      this.firstColumn = firstColumn;
+      this.lastColumn = lastColumn;
+      this.readAllFieldsAsVarChar = readAllFieldsAsVarChar;
+      this.evaluateFormulae = evaluateFormulae;
+      this.sheetName = sheetName;
+
+    }
+  }
+
+  public ExcelBatchReader(ExcelReaderConfig readerConfig) {
+    this.readerConfig = readerConfig;
+  }
+
+  @Override
+  public boolean open(FileSchemaNegotiator negotiator) {
+    verifyConfigOptions();
+    split = negotiator.split();
+    openFile(negotiator);
+    TupleMetadata schema = defineSchema();
+    this.loader = negotiator.build();
+    return true;
+  }
+
+  private void openFile(FileScanFramework.FileSchemaNegotiator negotiator) {
+    try {
+      String filePath = split.getPath().toString();
+      this.fsStream = negotiator.fileSystem().open(new Path(filePath));
+      this.workbook = new XSSFWorkbook(this.fsStream.getWrappedStream());
+    } catch (Exception e) {
+      throw UserException.dataReadError(e).message("Failed to open open input file: %s", split.getPath().toString()).message(e.getMessage()).build(logger);
+    }
+
+    // Evaluate formulae
+    if (readerConfig.evaluateFormulae) {
+      this.evaluator = workbook.getCreationHelper().createFormulaEvaluator();
+    }
+    this.workbook.setMissingCellPolicy(Row.MissingCellPolicy.CREATE_NULL_AS_BLANK);
+    this.sheet = getSheet();
+  }
+
+  /**
+   * This helper function gets the column headers.
+   * If the user specified no columns headers it populates an array with field names of field_n
+   */
+  private TupleMetadata defineSchema() {
+    // TODO Use case if there are no column headers
+    SchemaBuilder builder = new SchemaBuilder();
+    return getColumnHeaders(builder);
+  }
+
+  protected TupleMetadata getColumnHeaders(SchemaBuilder builder) {
+    //Get the field names
+    int columnCount = 0;
+    if (readerConfig.headerRow >= 0) {
+      columnCount = sheet.getRow(readerConfig.headerRow).getPhysicalNumberOfCells();
+    } else {
+      columnCount = sheet.getRow(0).getPhysicalNumberOfCells();
+    }
+    this.excelFieldNames = new ArrayList<>(columnCount);
+    this.rowIterator = sheet.iterator();
+
+    //If there are no headers, create columns names of field_n
+    if (readerConfig.headerRow == -1) {
+      String missingFieldName;
+      for (int i = 0; i < columnCount; i++) {
+        missingFieldName = MISSING_FIELD_NAME_HEADER + (i + 1);
+        ExcelFormatPlugin.makeColumn(builder, missingFieldName, TypeProtos.MinorType.VARCHAR);
+        excelFieldNames.add(i, missingFieldName);
+      }
+      return builder.buildSchema();
+    } else if (rowIterator.hasNext()) {
+      //Find the header row
+      while (this.lineCount < readerConfig.headerRow) {
+        Row row = rowIterator.next();
+        this.lineCount++;
+      }
+      //Get the header row and column count
+      Row row = rowIterator.next();
+      this.totalColumnCount = row.getLastCellNum();
+
+      //Read the header row
+      Iterator<Cell> cellIterator = row.cellIterator();
+      int colPosition = 0;
+      String tempColumnName = "";
+
+      while (cellIterator.hasNext()) {
+        Cell cell = cellIterator.next();
+        // TODO Potential NPE if cell evaluation is turned off
+        CellValue cellValue = evaluator.evaluate(cell);
+        switch (cellValue.getCellTypeEnum()) {
 
 Review comment:
   Are `STRING` and `NUMERIC` the only two cases? If not, what do we do for the other cases?

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