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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.metamodel.excel;
import java.util.Iterator;
import java.util.List;
import java.util.stream.Collectors;
import org.apache.metamodel.data.DataSet;
import org.apache.metamodel.data.EmptyDataSet;
import org.apache.metamodel.data.MaxRowsDataSet;
import org.apache.metamodel.query.SelectItem;
import org.apache.metamodel.schema.Column;
import org.apache.metamodel.schema.ColumnType;
import org.apache.metamodel.schema.MutableColumn;
import org.apache.metamodel.schema.MutableSchema;
import org.apache.metamodel.schema.MutableTable;
import org.apache.metamodel.schema.Schema;
import org.apache.metamodel.schema.Table;
import org.apache.metamodel.schema.naming.ColumnNamingContext;
import org.apache.metamodel.schema.naming.ColumnNamingContextImpl;
import org.apache.metamodel.schema.naming.ColumnNamingSession;
import org.apache.metamodel.schema.naming.ColumnNamingStrategy;
import org.apache.metamodel.util.FileHelper;
import org.apache.metamodel.util.Resource;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Workbook;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* The default {@link SpreadsheetReaderDelegate}, which uses POI's main user
* model to read spreadsheets: the Workbook class.
*/
final class DefaultSpreadsheetReaderDelegate implements SpreadsheetReaderDelegate {
private static final Logger logger = LoggerFactory.getLogger(DefaultSpreadsheetReaderDelegate.class);
private final Resource _resource;
private final ExcelConfiguration _configuration;
public DefaultSpreadsheetReaderDelegate(Resource resource, ExcelConfiguration configuration) {
_resource = resource;
_configuration = configuration;
}
@Override
public Schema createSchema(String schemaName) {
final MutableSchema schema = new MutableSchema(schemaName);
final Workbook wb = ExcelUtils.readWorkbook(_resource);
try {
for (int i = 0; i < wb.getNumberOfSheets(); i++) {
final Sheet currentSheet = wb.getSheetAt(i);
final MutableTable table = createTable(wb, currentSheet);
table.setSchema(schema);
schema.addTable(table);
}
return schema;
} finally {
FileHelper.safeClose(wb);
}
}
@Override
public DataSet executeQuery(Table table, List columns, int maxRows) {
final Workbook wb = ExcelUtils.readWorkbook(_resource);
final Sheet sheet = wb.getSheet(table.getName());
if (sheet == null || sheet.getPhysicalNumberOfRows() == 0) {
return new EmptyDataSet(columns.stream().map(SelectItem::new).collect(Collectors.toList()));
}
DataSet dataSet = ExcelUtils.getDataSet(wb, sheet, table, _configuration);
if (maxRows > 0) {
dataSet = new MaxRowsDataSet(dataSet, maxRows);
}
return dataSet;
}
@Override
public void notifyTablesModified() {
// do nothing
}
private MutableTable createTable(final Workbook wb, final Sheet sheet) {
final MutableTable table = new MutableTable(sheet.getSheetName());
if (sheet.getPhysicalNumberOfRows() <= 0) {
// no physical rows in sheet
return table;
}
final Iterator rowIterator = ExcelUtils.getRowIterator(sheet, _configuration, false);
if (!rowIterator.hasNext()) {
// no physical rows in sheet
return table;
}
Row row = null;
if (_configuration.isSkipEmptyLines()) {
while (row == null && rowIterator.hasNext()) {
row = rowIterator.next();
}
} else {
row = rowIterator.next();
}
final int columnNameLineNumber = _configuration.getColumnNameLineNumber();
if (columnNameLineNumber == ExcelConfiguration.NO_COLUMN_NAME_LINE) {
// get to the first non-empty line (no matter if lines are skipped
// or not we need to read ahead to figure out how many columns there
// are!)
while (row == null && rowIterator.hasNext()) {
row = rowIterator.next();
}
// build columns without any intrinsic column names
final ColumnNamingStrategy columnNamingStrategy = _configuration.getColumnNamingStrategy();
try (final ColumnNamingSession columnNamingSession = columnNamingStrategy.startColumnNamingSession()) {
final int offset = getColumnOffset(row);
for (int i = 0; i < offset; i++) {
columnNamingSession.getNextColumnName(new ColumnNamingContextImpl(i));
}
for (int j = offset; j < row.getLastCellNum(); j++) {
final ColumnNamingContext namingContext = new ColumnNamingContextImpl(table, null, j);
final Column column = new MutableColumn(columnNamingSession.getNextColumnName(namingContext),
ColumnType.STRING, table, j, true);
table.addColumn(column);
}
}
} else {
boolean hasColumns = true;
// iterate to the column name line number (if above 1)
for (int j = 1; j < columnNameLineNumber; j++) {
if (rowIterator.hasNext()) {
row = rowIterator.next();
} else {
hasColumns = false;
break;
}
}
if (hasColumns) {
createColumns(table, wb, row);
}
}
return table;
}
/**
* Builds columns based on row/cell values.
*
* @param table
* @param wb
* @param row
*/
private void createColumns(MutableTable table, Workbook wb, Row row) {
if (row == null) {
logger.warn("Cannot create columns based on null row!");
return;
}
final short rowLength = row.getLastCellNum();
final int offset = getColumnOffset(row);
// build columns based on cell values.
try (final ColumnNamingSession columnNamingSession = _configuration.getColumnNamingStrategy()
.startColumnNamingSession()) {
for (int j = offset; j < rowLength; j++) {
final Cell cell = row.getCell(j);
final String intrinsicColumnName = ExcelUtils.getCellValue(wb, cell);
final ColumnNamingContext columnNamingContext = new ColumnNamingContextImpl(table, intrinsicColumnName,
j);
final String columnName = columnNamingSession.getNextColumnName(columnNamingContext);
final Column column = new MutableColumn(columnName, ColumnType.VARCHAR, table, j, true);
table.addColumn(column);
}
}
}
/**
* Gets the column offset (first column to include). This is dependent on
* the row used for column processing and whether the skip empty columns
* property is set.
*
* @param row
* @return
*/
private int getColumnOffset(Row row) {
final int offset;
if (_configuration.isSkipEmptyColumns()) {
offset = row.getFirstCellNum();
} else {
offset = 0;
}
return offset;
}
}
