package com.creditdatamw.zerocell.handler;
import com.creditdatamw.zerocell.ReaderUtil;
import com.creditdatamw.zerocell.ZeroCellException;
import com.creditdatamw.zerocell.ZeroCellReader;
import com.creditdatamw.zerocell.column.ColumnInfo;
import com.creditdatamw.zerocell.converter.Converter;
import com.creditdatamw.zerocell.converter.NoopConverter;
import org.apache.poi.ss.util.CellAddress;
import org.apache.poi.ss.util.CellReference;
import org.apache.poi.xssf.usermodel.XSSFComment;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.File;
import java.lang.reflect.Field;
import java.util.*;
import static com.creditdatamw.zerocell.converter.ConverterUtils.convertValueToType;
final class EntityExcelSheetHandler<T> implements ZeroCellReader {
private EntityHandler<T> entityHandler;
private final Logger LOGGER = LoggerFactory.getLogger(EntityExcelSheetHandler.class);
private final ColumnInfo rowNumberColumn;
private final Map<Integer, ColumnInfo> columns;
private final List<T> entities;
private final Converter NOOP_CONVERTER = new NoopConverter();
private final Map<Integer, Converter> converters;
private boolean isHeaderRow = false;
private int currentRow = -1;
private int currentCol = -1;
private EmptyColumnCounter emptyColumnCounter = new EmptyColumnCounter();
private T cur;
EntityExcelSheetHandler(EntityHandler<T> entityHandler, ColumnInfo rowNumberColumn, Map<Integer, ColumnInfo> columns) {
this.entityHandler = entityHandler;
this.rowNumberColumn = rowNumberColumn;
this.columns = columns;
this.converters = cacheConverters();
this.entities = new ArrayList<>();
}
private Map<Integer, Converter> cacheConverters() {
Map<Integer, Converter> mappedConverters = new HashMap<>();
for (ColumnInfo columnInfo : columns.values()) {
mappedConverters.put(columnInfo.getIndex(), NOOP_CONVERTER);
try {
if (!columnInfo.getConverterClass().equals(NoopConverter.class)) {
mappedConverters.put(columnInfo.getIndex(), (Converter) columnInfo.getConverterClass().newInstance());
}
} catch (InstantiationException | IllegalAccessException e) {
LOGGER.error("Failed to instantiate Converter class: {}", columnInfo.getConverterClass());
}
}
return mappedConverters;
}
/**
* Returns a list of entities loaded from the provided Excel file
* @param file the Excel file to load data from
* @param sheet the sheet to load data from
* @return list of entities from the sheet
*/
@Override
public List<T> read(File file, String sheet) {
/**
* We don't need to process the file here since that's
* handled in {@link ReaderUtil} which MUST be used when using this class
*/
return Collections.unmodifiableList(this.entities);
}
void clear() {
this.currentRow = -1;
this.currentCol = -1;
this.cur = null;
this.entities.clear();
}
@Override
@SuppressWarnings("unchecked")
public void startRow(int i) {
currentRow = i;
//skip the current row
if (currentRow - entityHandler.getSkipFirstNRows() < 0) return;
currentRow = currentRow - entityHandler.getSkipFirstNRows();
// skip the header row
if (currentRow == 0) {
isHeaderRow = true;
return;
} else {
isHeaderRow = false;
}
try {
cur = (T) entityHandler.getEntityClass().newInstance();
// Write to the field with the @RowNumber annotation here if it exists
if (!Objects.isNull(rowNumberColumn)) {
writeColumnField(cur, String.valueOf(currentRow), rowNumberColumn, currentRow);
}
} catch (InstantiationException | IllegalAccessException e) {
throw new ZeroCellException("Failed to create and instance of " + entityHandler.getEntityClass().getName(), e);
}
}
private boolean isRowNumberValueSetted() {
return entityHandler.getMaxRowNumber() != 0 &&
entityHandler.getMaxRowNumber() != entityHandler.getSkipFirstNRows();
}
@Override
public void endRow(int i) {
if (isRowNumberValueSetted() && i > entityHandler.getMaxRowNumber()) {
return;
}
if (!Objects.isNull(cur)) {
if (entityHandler.isSkipEmptyRows() && emptyColumnCounter.rowIsEmpty()) {
LOGGER.warn("Row#{} skipped because it is empty", i);
} else {
this.entities.add(cur);
}
}
cur = null;
emptyColumnCounter.reset();
}
@Override
public void cell(String cellReference, String formattedValue, XSSFComment xssfComment) {
if (cellReference == null) {
cellReference = new CellAddress(currentRow, currentCol).formatAsString();
}
int column = new CellReference(cellReference).getCol();
currentCol = column;
ColumnInfo currentColumnInfo = columns.get(column);
if (Objects.isNull(currentColumnInfo)) {
return;
}
if (isHeaderRow && !entityHandler.isSkipHeaderRow()) {
if (!currentColumnInfo.getName().equalsIgnoreCase(formattedValue.trim())) {
throw new ZeroCellException(String.format("Expected Column '%s' but found '%s'", currentColumnInfo.getName(), formattedValue));
}
}
// Prevent from trying to write to a null instance
if (Objects.isNull(cur)) return;
if (entityHandler.isSkipEmptyRows()) {
if (formattedValue == null || formattedValue.isEmpty()) {
emptyColumnCounter.increment();
}
}
writeColumnField(cur, formattedValue, currentColumnInfo, currentRow);
}
/**
* Write the value read from the excel cell to a field
*
* @param object the object to write to
* @param formattedValue the value read from the current excel column/row
* @param currentColumnInfo Column metadata
* @param rowNum the row number
*/
private void writeColumnField(T object, String formattedValue, ColumnInfo currentColumnInfo, int rowNum) {
String fieldName = currentColumnInfo.getFieldName();
try {
Converter converter = NOOP_CONVERTER;
if (currentColumnInfo.getIndex() != -1) {
converter = converters.get(currentColumnInfo.getIndex());
}
Object value = null;
// Don't use a converter if there isn't a custom one
if (converter instanceof NoopConverter) {
value = convertValueToType(currentColumnInfo.getType(), formattedValue, currentColumnInfo.getName(), rowNum);
} else {
// Handle any exceptions thrown by the converter - this stops execution of the whole process
try {
value = converter.convert(formattedValue, currentColumnInfo.getName(), rowNum);
} catch (Exception e) {
throw new ZeroCellException(String.format("%s threw an exception while trying to convert value %s ", converter.getClass().getName(), formattedValue), e);
}
}
Field field = entityHandler.getEntityClass()
.getDeclaredField(currentColumnInfo.getFieldName());
boolean access = field.isAccessible();
if (!access) {
field.setAccessible(true);
}
field.set(cur, value);
field.setAccessible(field.isAccessible() && access);
} catch (IllegalArgumentException e) {
throw new ZeroCellException(String.format("Failed to write value %s to field %s at row %s", formattedValue, fieldName, rowNum));
} catch (NoSuchFieldException | IllegalAccessException e) {
LOGGER.error("Failed to set field: {}", fieldName, e);
}
}
@Override
public void headerFooter(String text, boolean b, String tagName) {
// Skip, no headers or footers in CSV
}
private class EmptyColumnCounter {
private int count = 0;
void increment() {
this.count += 1;
}
boolean rowIsEmpty() {
return this.count >= columns.size();
}
void reset() {
count = 0;
}
}
}
