tech.tablesaw.io.FileReader Maven / Gradle / Ivy
package tech.tablesaw.io;
import static tech.tablesaw.api.ColumnType.SKIP;
import com.google.common.base.Strings;
import com.google.common.collect.Lists;
import com.univocity.parsers.common.AbstractParser;
import java.io.Reader;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.Random;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import tech.tablesaw.api.ColumnType;
import tech.tablesaw.api.Table;
import tech.tablesaw.columns.AbstractColumnParser;
import tech.tablesaw.columns.Column;
public abstract class FileReader {
private static Logger logger = LoggerFactory.getLogger(FileReader.class);
private static final int UNLIMITED_SAMPLE_SIZE = -1;
/**
* Returns an array containing the inferred columnTypes for the file being read, as calculated by
* the ColumnType inference logic. These types may not be correct.
*/
public ColumnType[] getColumnTypes(
Reader reader, ReadOptions options, int linesToSkip, AbstractParser parser) {
parser.beginParsing(reader);
for (int i = 0; i < linesToSkip; i++) {
parser.parseNext();
}
ColumnTypeDetector detector = new ColumnTypeDetector(options.columnTypesToDetect());
return detector.detectColumnTypes(
new Iterator() {
String[] nextRow = parser.parseNext();
@Override
public boolean hasNext() {
return nextRow != null;
}
@Override
public String[] next() {
if (!hasNext()) {
throw new NoSuchElementException();
}
String[] tmp = nextRow;
nextRow = parser.parseNext();
return tmp;
}
},
options);
}
private String cleanName(String name) {
return name.trim();
}
/** Returns the column names for each column in the source. */
public String[] getColumnNames(
ReadOptions options, ColumnType[] types, AbstractParser parser) {
if (options.header()) {
String[] headerNames = parser.parseNext();
// work around issue where Univocity returns null if a column has no header.
for (int i = 0; i < headerNames.length; i++) {
if (headerNames[i] == null) {
headerNames[i] = "C" + i;
} else {
headerNames[i] = headerNames[i].trim();
}
}
return headerNames;
} else {
// Placeholder column names for when the file read has no header
String[] headerNames = new String[types.length];
for (int i = 0; i < types.length; i++) {
headerNames[i] = "C" + i;
}
return headerNames;
}
}
protected Table parseRows(
ReadOptions options,
boolean headerOnly,
Reader reader,
ColumnType[] types,
AbstractParser parser) {
return parseRows(options, headerOnly, reader, types, parser, UNLIMITED_SAMPLE_SIZE);
}
protected Table parseRows(
ReadOptions options,
boolean headerOnly,
Reader reader,
ColumnType[] types,
AbstractParser parser,
int sampleSize) {
parser.beginParsing(reader);
Table table = Table.create(options.tableName());
List headerRow = Lists.newArrayList(getColumnNames(options, types, parser));
for (int x = 0; x < types.length; x++) {
if (types[x] != SKIP) {
String columnName = cleanName(headerRow.get(x));
if (Strings.isNullOrEmpty(columnName)) {
columnName = "Column " + table.columnCount();
}
Column newColumn = types[x].create(columnName);
table.addColumns(newColumn);
}
}
if (!headerOnly) {
String[] columnNames = selectColumnNames(headerRow, types);
int[] columnIndexes = new int[columnNames.length];
for (int i = 0; i < columnIndexes.length; i++) {
// get the index in the original table, which includes skipped fields
columnIndexes[i] = headerRow.indexOf(columnNames[i]);
}
addRows(options, types, parser, table, columnIndexes, sampleSize);
}
return table;
}
private void addRows(
ReadOptions options,
ColumnType[] types,
AbstractParser reader,
Table table,
int[] columnIndexes,
int sampleSize) {
String[] nextLine;
Map> parserMap = getParserMap(options, table);
Random random = new Random(0);
// Add the rows
for (int rowNumber = options.header() ? 1 : 0;
(nextLine = reader.parseNext()) != null;
rowNumber++) {
// validation
if (nextLine.length < types.length) {
if (nextLine.length == 1 && Strings.isNullOrEmpty(nextLine[0])) {
logger.error("Warning: Invalid file. Row " + rowNumber + " is empty. Continuing.");
continue;
} else {
Exception e =
new IndexOutOfBoundsException(
"Row number "
+ rowNumber
+ " contains "
+ nextLine.length
+ " columns. "
+ types.length
+ " expected.");
throw new AddCellToColumnException(e, 0, rowNumber, table.columnNames(), nextLine);
}
} else if (nextLine.length > types.length) {
throw new IllegalArgumentException(
"Row number "
+ rowNumber
+ " contains "
+ nextLine.length
+ " columns. "
+ types.length
+ " expected.");
}
int samplesCount = table.rowCount();
if (sampleSize < 0 || samplesCount < sampleSize) {
addValuesToColumns(table, columnIndexes, nextLine, parserMap, rowNumber, -1);
} else {
// find a row index to replace
int randomIndex = random.nextInt(samplesCount + 1);
// replace index if it is smaller than numSamples, otherwise ignore it.
if (randomIndex < sampleSize) {
addValuesToColumns(table, columnIndexes, nextLine, parserMap, rowNumber, randomIndex);
}
}
}
}
private void addValuesToColumns(
Table table,
int[] columnIndexes,
String[] nextLine,
Map> parserMap,
int rowNumber,
int rowIndex) {
// append each column that we're including (not skipping)
int cellIndex = 0;
for (int columnIndex : columnIndexes) {
Column column = table.column(cellIndex);
AbstractColumnParser parser = parserMap.get(column.name());
try {
String value = nextLine[columnIndex];
if (rowIndex >= 0) {
column.set(rowIndex, value, parser);
} else {
column.appendCell(value, parser);
}
} catch (Exception e) {
throw new AddCellToColumnException(
e, columnIndex, rowNumber, table.columnNames(), nextLine);
}
cellIndex++;
}
}
private Map> getParserMap(ReadOptions options, Table table) {
Map> parserMap = new HashMap<>();
for (Column column : table.columns()) {
AbstractColumnParser parser = column.type().customParser(options);
parserMap.put(column.name(), parser);
}
return parserMap;
}
/** Reads column names from header, skipping any for which the type == SKIP */
private String[] selectColumnNames(List names, ColumnType[] types) {
List header = new ArrayList<>();
for (int i = 0; i < types.length; i++) {
if (types[i] != SKIP) {
String name = names.get(i);
name = name.trim();
header.add(name);
}
}
String[] result = new String[header.size()];
return header.toArray(result);
}
protected String getTypeString(Table structure) {
StringBuilder buf = new StringBuilder();
buf.append("ColumnType[] columnTypes = {");
buf.append(System.lineSeparator());
Column typeCol = structure.column("Column Type");
Column indxCol = structure.column("Index");
Column nameCol = structure.column("Column Name");
// add the column headers
int typeColIndex = structure.columnIndex(typeCol);
int indxColIndex = structure.columnIndex(indxCol);
int nameColIndex = structure.columnIndex(nameCol);
int typeColWidth = typeCol.columnWidth();
int indxColWidth = indxCol.columnWidth();
int nameColWidth = nameCol.columnWidth();
final char padChar = ' ';
for (int r = 0; r < structure.rowCount(); r++) {
String cell = Strings.padEnd(structure.get(r, typeColIndex) + ",", typeColWidth, padChar);
buf.append(cell);
buf.append(" // ");
cell = Strings.padEnd(structure.getUnformatted(r, indxColIndex), indxColWidth, padChar);
buf.append(cell);
buf.append(' ');
cell = Strings.padEnd(structure.getUnformatted(r, nameColIndex), nameColWidth, padChar);
buf.append(cell);
buf.append(' ');
buf.append(System.lineSeparator());
}
buf.append("}");
buf.append(System.lineSeparator());
return buf.toString();
}
}
© 2015 - 2025 Weber Informatics LLC | Privacy Policy