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package com.github.timo_reymann.csv_parser.io;
import com.github.timo_reymann.csv_parser.meta.CsvMetaDataReader;
import com.github.timo_reymann.csv_parser.util.Converter;
import lombok.AccessLevel;
import lombok.Setter;
import java.io.*;
import java.lang.reflect.Field;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.util.HashMap;
import java.util.Map;
import java.util.function.Function;
import java.util.stream.Stream;
/**
* Reader for csv files
*
* @author Timo Reymann
* @since 20.12.17
*/
public class CsvReader implements AutoCloseable, Flushable, Closeable {
/**
* Underlying file reader
*/
@Setter(AccessLevel.PROTECTED)
private FileReader fileReader;
/**
* Buffered reader for reading lines
*/
@Setter(AccessLevel.PROTECTED)
private BufferedReader bufferedReader;
/**
* Class object for type to read from file
*/
@Setter(AccessLevel.PROTECTED)
private Class clazz;
/**
* CSV file to read
*/
@Setter(AccessLevel.PROTECTED)
private File file;
/**
* Csv file has header in first line
*/
private boolean hasHeading = false;
/**
* Seperator for csv file
*/
private String seperator = Seperator.SEMICOLON;
/**
* Headings for file, if headings detection is enabled for this file
*/
private HashMap headings = new HashMap<>();
/**
* Meta data api
*/
private CsvMetaDataReader csvMetaDataReader;
/**
* Converter api
*/
private final Converter converter = new Converter();
/**
* Create CsvReader
*
* @param file File to read
* @param clazz Class of bean to read
* @param hasHeading Has the file headers for column names
* @throws FileNotFoundException File was not found on disk
*/
public CsvReader(File file, Class clazz, boolean hasHeading) throws FileNotFoundException {
this.file = file;
this.clazz = clazz;
this.csvMetaDataReader = new CsvMetaDataReader<>(clazz);
this.setHasHeading(hasHeading);
init();
}
/**
* Create new instance
*
* @param fileName Name of file
* @param clazz Class of bean
* @throws FileNotFoundException File was not found on disk
*/
public CsvReader(String fileName, Class clazz) throws FileNotFoundException {
this(new File(fileName), clazz, false);
}
/**
* Create new instance
*
* @param fileName Name of file
* @param clazz Class of bean
* @param hasHeading File has first line with headings
* @throws FileNotFoundException File was not found on disk
*/
public CsvReader(String fileName, Class clazz, boolean hasHeading) throws FileNotFoundException {
this(new File(fileName), clazz, hasHeading);
}
/**
* Map splitted data of line to object of bean
*
* @param data Data to map
* @return Mapped object
* @throws InstantiationException Error creating bean instance, this occurs when
* no default constructor without parameters is available or an exception is thrown during initalization
* @throws IllegalAccessException Constructor is private
*/
private T map(String[] data) throws InstantiationException, IllegalAccessException {
if (hasHeading) {
return mapByHeading(data);
}
return mapByIndex(data);
}
/**
* Map bean by heading in annotations
*
* @param data Data to set
* @return Mapped bean instance
* @throws IllegalAccessException Constructor is private
* @throws InstantiationException Error creating bean instance, this occurs when
* no default constructor without parameters is available or an exception is thrown during initalization
*/
private T mapByHeading(String[] data) throws IllegalAccessException, InstantiationException {
T obj = clazz.newInstance();
HashMap effectiveValueForColumnMapping = csvMetaDataReader.getEffectiveValueForColumnMapping();
for (Map.Entry headingEntry : headings.entrySet()) {
String val;
try {
val = data[headingEntry.getKey()];
} catch (ArrayIndexOutOfBoundsException e) { // No element found
val = null;
}
Field field = effectiveValueForColumnMapping.get(headingEntry.getValue());
// Ignore if field is not mapped
if (field != null) {
setValue(field, obj, val);
}
}
return obj;
}
/**
* Set value for field, this automatically picks the type for the field
*
* @param field Field
* @param obj Object to set field in
* @param value Value to set to field
* @throws IllegalAccessException Error setting field
*/
private void setValue(Field field, Object obj, String value) throws IllegalAccessException {
Class type = field.getType();
Function mapper = null;
// Basic types
if (type.isAssignableFrom(String.class)) {
mapper = String::valueOf;
} else if (type.isAssignableFrom(Integer.class)) {
mapper = converter::convertToInt;
} else if (type.isAssignableFrom(Boolean.class)) {
mapper = converter::convertToBoolean;
} else if (type.isAssignableFrom(Double.class)) {
mapper = converter::convertToDouble;
} else if (type.isAssignableFrom(Float.class)) {
mapper = converter::convertToFloat;
} else if (type.isAssignableFrom(LocalDate.class)) {
mapper = (input) -> converter.convertToLocalDate(getFormatForColumn(field), input);
} else if (type.isAssignableFrom(LocalDateTime.class)) {
mapper = (input) -> converter.convertToLocalDateTime(getFormatForColumn(field), input);
} else {
// 'Castable' types, may produce error
field.set(obj, field.getType().cast(value));
}
converter.setField(field, obj, mapper.apply(value));
}
private String getFormatForColumn(Field field) {
try {
return csvMetaDataReader.getCsvColumnForField(field).format();
} catch (Exception e) {
throw new InvalidArgumentException("format", "Format for column must be set if the datatype requires a format");
}
}
/**
* Map bean by index specified in annotation
*
* @param data Data to set
* @return Mapped bean
* @throws IllegalAccessException Constructor is private
* @throws InstantiationException Error creating bean instance, this occurs when
* no default constructor without parameters is available or an exception is thrown during initalization
*/
private T mapByIndex(String[] data) throws IllegalAccessException, InstantiationException {
T obj = clazz.newInstance();
HashMap effectiveMapping = csvMetaDataReader.getEffectiveValueForColumnMapping();
for (int i = 0, dataLength = data.length; i < dataLength; i++) {
Field field = effectiveMapping.get(i);
if (field != null) {
setValue(field, obj, data[i]);
}
}
return obj;
}
/**
* Read line from underlying {@link BufferedReader} and split it by seperator
*
* @return String array with columns split by seperator
* @throws IOException Error reading line
*/
private String[] readLineAndSplitBySeperator() throws IOException {
return splitBySeperator(bufferedReader.readLine());
}
/**
* Split string by seperator
*
* @param line Line to split
* @return String array with data
*/
private String[] splitBySeperator(String line) {
return line.split(seperator);
}
/**
* Get heading from file, this automatically skips the first line for further processing
*
* @throws IOException Error reading first line
*/
private void getHeadings() throws IOException {
if (!hasHeading) {
return;
}
headings.clear();
String[] headingStrings = readLineAndSplitBySeperator();
for (int i = 0; i < headingStrings.length; i++) {
headings.put(i, headingStrings[i]);
}
}
/**
* Intialize {@link FileReader} instance and {@link BufferedReader} for specified file
*
* @throws FileNotFoundException File was not found on disk
*/
private void init() throws FileNotFoundException {
fileReader = new FileReader(file);
bufferedReader = new BufferedReader(fileReader);
try {
getHeadings();
} catch (IOException e) {
throw new FileNotFoundException();
}
}
/**
* Close {@link FileReader} and {@link BufferedReader} instance
*
* @throws IOException Error while trying to close readers
*/
public void close() throws IOException {
if (this.fileReader != null) {
this.fileReader.close();
}
if (this.bufferedReader != null) {
this.bufferedReader.close();
}
}
/**
* Read line from csv file
*
* @return Mapped bean
* @throws IOException Error reading line from csv file
* @throws IllegalAccessException Error mapping fields
* @throws InstantiationException Error creating new bean instance for mapping
*/
public T readLine() throws IOException, IllegalAccessException, InstantiationException {
return map(readLineAndSplitBySeperator());
}
/**
* Get stream with remaining lines from {@link BufferedReader} already mapped to beans,
* if an error occurred during mapping, its element in list is null
*
* @return Stream with mapped bean objects
*/
public Stream lines() {
return bufferedReader.lines()
.map(l -> {
try {
return map(splitBySeperator(l));
} catch (InstantiationException | IllegalAccessException e) {
// Ignore Exception
}
return null;
});
}
/**
* Flush {@link FileReader} and {@link BufferedReader}
*
* @throws IOException Error flushing readers
*/
@Override
public void flush() throws IOException {
try {
close();
} catch (Exception e) {
throw new IOException(e);
}
init();
}
/**
* Set has heading property
*
* @param hasHeading Has heading (true) or not (false)
*/
public void setHasHeading(boolean hasHeading) {
this.hasHeading = hasHeading;
}
/**
* Set separator for splitting rows
*
* @param seperator Seperator
*/
public void setSeperator(String seperator) {
this.seperator = seperator;
}
/**
* Builder for easily creating csv reader
*
* @param Type of bean saved in csv file
*/
public static class Builder {
/**
* Final csv reader object
*/
private CsvReader csvReader;
/**
* Class of bean
*/
private Class clazz;
/**
* Csv file
*/
private File file;
/**
* The file has a first line with headings
*/
private boolean hasHeading = false;
/**
* Separator for file
*/
private String seperator;
/**
* Set class of bean
*
* @param clazz Class object for bean
* @return Current builder
*/
public Builder forClass(Class clazz) {
this.clazz = clazz;
return this;
}
/**
* Set file to read from
*
* @param file CSV file
* @return Current builder
*/
public Builder file(File file) {
this.file = file;
return this;
}
/**
* Set seperator for csv reader, default it is set to ';'
*
* @param seperator Seperator
* @return Current builder
*/
public Builder seperatedBy(String seperator) {
this.seperator = seperator;
return this;
}
/**
* File to read has first row with heading
*
* @return Current builder
*/
public Builder hasHeading() {
this.hasHeading = true;
return this;
}
/**
* Build csv reader instance
*
* @return Ready to use csv reader
*/
public CsvReader build() {
if (file == null || !file.exists()) {
throw new InvalidArgumentException("file", file);
}
if (clazz == null) {
throw new InvalidArgumentException("class", clazz);
}
try {
csvReader = new CsvReader(file, clazz, hasHeading);
} catch (FileNotFoundException e) {
throw new InvalidArgumentException("file", e);
}
csvReader.setHasHeading(this.hasHeading);
if (this.seperator != null && !this.seperator.isEmpty()) {
csvReader.setSeperator(seperator);
}
return csvReader;
}
}
}
