CSV file reader
/*
* Copyright (C) 2010 takaji
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
//package dakside.csv;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.util.ArrayList;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
* CSV file reader
*
* @author Takaji
*/
public final class CSVFileReader {
private CSVFormat format;
private final BufferedReader reader;
private int col = 1;
private int row = 1;
private StringBuilder element = new StringBuilder(); // store current
// element
private CSVLine currentLine = null; // current CSV line
private boolean isOpened = false; // a string is opened with text delimiter
// <editor-fold defaultstate="collapsed" desc="Constructors">
public CSVFileReader(Reader reader) {
//validate parameter
checkNotNull(reader, "Reader cannot be null");
this.reader = new BufferedReader(reader);
this.format = new CSVFormat();
}
public CSVFileReader(Reader reader, CSVFormat format) {
//validate parameter
checkNotNull(reader, "Reader cannot be null");
this.reader = new BufferedReader(reader);
this.format = format;
}
public CSVFileReader(BufferedReader reader) throws FileNotFoundException {
//validate parameter
checkNotNull(reader, "Reader cannot be null");
this.reader = reader;
this.format = new CSVFormat();
}
public CSVFileReader(BufferedReader reader, CSVFormat format) {
//validate parameter
checkNotNull(reader, "Reader cannot be null");
this.reader = reader;
this.format = format;
}
public CSVFileReader(String filename) throws CSVException {
//validate parameter
checkNotNull(filename, "File name cannot be empty");
try {
this.reader = new BufferedReader(new FileReader(filename));
} catch (FileNotFoundException ex) {
Logger.getLogger(CSVFileReader.class.getName()).log(Level.SEVERE, null, ex);
throw new CSVException("Cannot create reading buffer", ex);
}
this.format = new CSVFormat();
}
public CSVFileReader(File f) {
//validate parameter
checkNotNull(f, "File object cannot be null");
try {
this.reader = new BufferedReader(new FileReader(f));
} catch (FileNotFoundException ex) {
Logger.getLogger(CSVFileReader.class.getName()).log(Level.SEVERE, null, ex);
throw new CSVException("Cannot create reading buffer", ex);
}
this.format = new CSVFormat();
}
public CSVFileReader(InputStream input) {
//validate parameter
checkNotNull(input, "InputStream cannot be null");
reader = new BufferedReader(new InputStreamReader(input));
this.format = new CSVFormat();
}
public CSVFileReader(String filename, CSVFormat format) {
//validate parameter
checkNotNull(filename, "File name cannot be empty");
try {
this.reader = new BufferedReader(new FileReader(filename));
} catch (FileNotFoundException ex) {
Logger.getLogger(CSVFileReader.class.getName()).log(Level.SEVERE, null, ex);
throw new CSVException("Cannot create reading buffer", ex);
}
this.format = format;
}
public CSVFileReader(File f, CSVFormat format) {
//validate parameter
checkNotNull(f, "File object cannot be null");
try {
this.reader = new BufferedReader(new FileReader(f));
} catch (FileNotFoundException ex) {
Logger.getLogger(CSVFileReader.class.getName()).log(Level.SEVERE, null, ex);
throw new CSVException("Cannot create reading buffer", ex);
}
this.format = format;
}
public CSVFileReader(InputStream input, CSVFormat format) {
//validate parameter
checkNotNull(input, "InputStream cannot be null");
reader = new BufferedReader(new InputStreamReader(input));
this.format = format;
}
// </editor-fold>
/**
* read next char
*/
private int read() throws IOException {
int next = -1;
next = reader.read();
if (next != -1) {
col++;
}
return next;
}
/**
* Do carriage return
*/
private void carriageReturn() {
synchronized (this) {
row++;
col = 1;
}
}
/**
* Finished read a cell, flush to current line
*/
private void flushElement() {
currentLine.add(element.toString());
element.setLength(0); // reset current element
isOpened = false;
}
/**
* Parse a CSV string to data
*
* @param rawData
* @return a simple CSV object with data. null if the raw data cannot be
* parse
* @throw CSVException
*/
public CSVLine readLine() throws CSVException {
if (reader == null) {
throw new CSVException("No reader found.");
}
synchronized (this) {
element = new StringBuilder(); // store current
// element
currentLine = null; // current CSV line
isOpened = false; // a string is opened with text delimiter
try {
int currentInt = -1;
// parse data
while ((currentInt = read()) != -1) {
if (currentLine == null) {
currentLine = new CSVLine();
}
// reach field delimiter
if (currentInt == format.getTextDelimiter()) {
if (isOpened) {
// check next char is escape?
if ((currentInt = read()) != -1) {
if (currentInt == format.getTextDelimiter()) {
// is special char
element.append(format.getTextDelimiter());
continue;
} else {
// is close string then flush
flushElement();
// next char must be field delimiter
//or a line terminator
if (currentInt == format.getFieldDelimiter()) {
continue;
} else if (currentInt == format.getLineTerminator()) {
carriageReturn();
return currentLine;
} else {
raiseExpected(format.getFieldDelimiter(),
(char) currentInt);
}
continue;
}
} else {
flushElement();
continue;
}
} else {
// is first open of the string
isOpened = true;
continue;
}
}
if (!isOpened) {
// ignore character
if (format.isIgnored((char) currentInt)) {
continue; // just ignore
} else if (currentInt == format.getLineTerminator()) {
flushElement();
if (currentLine != null) {
carriageReturn();
}
return currentLine;
}
}
// meet field delimiter
if (currentInt == format.getFieldDelimiter()) {
if (isOpened) {
element.append((char) currentInt);
continue;
} else {
flushElement();
continue;
}
}
// otherwise, it's a normal character, just add
element.append((char) currentInt);
}// continue while
// flush last element if needed
if (element != null && currentLine != null) {
flushElement();
}
} catch (Exception ex) {
ex.printStackTrace();
raiseException(ex);
}
// if currentLine exists, return carriage
if (currentLine != null) {
carriageReturn();
}
}// end of synchronize
return currentLine;
}
// <editor-fold defaultstate="collapsed" desc="Exception related tasks">
/**
* Expected char [expected] but found another char [actual] so we
* throw an exception here.
* @param expected
* @param actual
*/
private void raiseExpected(char expected, char actual) {
raiseException(new Exception(String.format(
"Invalid data. Expected [%s] but [%s] was found.", String.valueOf(expected), String.valueOf(actual))));
}
private void raiseException(Exception ex) {
throw new CSVException("Error happened while processing at row: " + row
+ " - col: " + (col - 1) + ")", ex);
}
/**
* Check if argument null then throw a new CSV Exception
* @param argument
*/
public static void checkNotNull(Object argument, String message) throws CSVException {
if (argument == null) {
throw new CSVException(message);
}
}
/**
* Close current reader and underline stream
*/
public void close() {
try {
synchronized (reader) {
reader.close();
}
} catch (Exception ex) {
Logger.getLogger(CSVFileReader.class.getName()).log(Level.SEVERE,
null, ex);
}
}
// </editor-fold>
// <editor-fold defaultstate="collapsed" desc="Quick CSV reading">
/**
* Parse a CSV stream to data
*
* @param stream
* InputStream
* @return a simple CSV object with data. null if the raw data cannot be
* parse
*/
public static CSVFile parse(InputStream stream) throws CSVException {
try {
CSVFileReader reader = new CSVFileReader(stream);
CSVFile file = new CSVFile();
CSVLine line = null;
do {
line = reader.readLine();
file.append(line);
} while (line != null);
return file;
} catch (Exception ex) {
throw new CSVException(ex);
}
}
/**
* Parse file content to CSV
*
* @param path
* @return
*/
public static CSVFile parseFile(String path) {
if (path == null || !(new File(path)).exists()) {
throw new CSVException("Invalid path");
}
try {
return parse(new FileInputStream(path));
} catch (Exception ex) {
Logger.getLogger(CSVFile.class.getName()).log(Level.SEVERE, null,
ex);
throw new CSVException(ex);
}
}
// </editor-fold>
}
class CSVFile {
private ArrayList<CSVLine> lines; //lines inside a CSV file
/**
* Default constructor
*/
public CSVFile() {
this.lines = new ArrayList<CSVLine>();
}
public CSVLine[] getLines() {
return this.lines.toArray(new CSVLine[0]);
}
/**
* Get line at a specified index
* @param idx
* @return
* @throws IndexOutOfBoundsException
*/
public CSVLine getLine(int idx) throws IndexOutOfBoundsException{
return this.lines.get(idx);
}
/**
* Add a new line to current csv
* @return new line object
*/
public CSVLine newLine() {
CSVLine line = new CSVLine();
this.lines.add(line);
return line;
}
/**
* get number of line
* @return number of line
*/
public int size() {
return this.lines.size();
}
/**
* discard a line at the specified index
* @param idx
*/
public void discard(int idx) {
if (idx >= 0 && idx < size()) {
this.lines.remove(idx);
}
}
/**
* discard empty record
*/
public void discardEmpty() {
for (int i = this.lines.size() - 1; i > -1; i--) {
if (this.lines.get(i) == null || this.lines.get(i).isEmpty()) {
discard(i);
}
}
}
/**
* append a CSV line to file (line is ignored if null)
* @param line
*/
void append(CSVLine line) {
if (line == null) {
return;
}
this.lines.add(line);
}
}
class CSVException extends RuntimeException {
private static final long serialVersionUID = 1L;
public CSVException() {
}
public CSVException(Throwable throwable) {
super(throwable);
}
public CSVException(String message) {
super(message);
}
public CSVException(String message, Throwable throwable) {
super(message, throwable);
}
}
class CSVLine {
private ArrayList<Object> elements;
/**
* Default constructor
*/
public CSVLine() {
this.elements = new ArrayList<Object>();
}
/**
* Get all elements (cells) inside a line
* @return empty String array if there's no element found inside
*/
public Object[] getElements() {
return this.elements.toArray();
}
/**
* Get element at index
* @param idx
* @return
* @throws IndexOutOfBoundsException
*/
public Object getElementAt(int idx) throws IndexOutOfBoundsException {
return elements.get(idx);
}
/**
* Set element at
* @param idx
* @param value
* @throws IndexOutOfBoundsException
*/
public void setElementAt(int idx, Object value) throws IndexOutOfBoundsException {
elements.set(idx, value);
}
/**
* count elements inside this line
* @return
*/
public int size() {
return elements.size();
}
/**
* Add a new element
*/
public CSVLine add(Object obj) {
this.elements.add(obj);
return this;
}
/**
* if CSV line is empty
* @return
*/
public boolean isEmpty() {
return this.elements.isEmpty();
}
/**
* Remove all elements
*/
public void clear() {
this.elements.clear();
}
/**
* Remove element at a specified index
* @param idx
* @throws IndexOutOfBoundsException
*/
public void remove(int idx) throws IndexOutOfBoundsException {
elements.remove(idx);
}
/**
* Trim down or expand with null cell to a new length
* @param newLength
*/
public void setLength(int newLength) {
if (elements.size() > newLength) {
//trim down
while (elements.size() > newLength) {
elements.remove(elements.size() - 1);
}
} else {
//add more
while (elements.size() < newLength) {
add(null);
}
}
}
}
class CSVFormat {
private String charset;
private char fieldDelimiter;
private char textDelimiter;
private char lineTerminator;
private char[] ignoreCharacters;
/**
* Construct a standard CSV format
*/
public CSVFormat() {
this.setCharset("UTF-8");
this.setFieldDelimiter(',');
this.setTextDelimiter('"');
//auto detect line separator
String s = System.getProperty("line.separator");
if (s.length() > 0) {
this.setLineTerminator(s.charAt(0));
char[] ignoreChars = new char[s.length() - 1];
for (int i = 1; i < s.length(); i++) {
ignoreChars[i-1] = s.charAt(i);
}
this.setIgnoreCharacters(ignoreChars);
} else {
this.setLineTerminator('\n');
this.setIgnoreCharacters(new char[]{'\r'});
}
}
/**
* @param lineTerminator
* the lineTerminator to set
*/
public void setLineTerminator(char lineTerminator) {
this.lineTerminator = lineTerminator;
}
/**
* @return the lineTerminator
*/
public char getLineTerminator() {
return lineTerminator;
}
/**
* @param ignoreCharacters
* the ignoreCharacters to set
*/
public void setIgnoreCharacters(char[] ignoreCharacters) {
this.ignoreCharacters = ignoreCharacters;
}
/**
* @return the ignoreCharacters
*/
public char[] getIgnoreCharacters() {
return ignoreCharacters;
}
/**
* @param charset
* the charset to set
*/
public void setCharset(String charset) {
this.charset = charset;
}
/**
* @return the charset
*/
public String getCharset() {
return charset;
}
/**
* @param fieldDelimiter
* the fieldDelimiter to set
*/
public void setFieldDelimiter(char fieldDelimiter) {
this.fieldDelimiter = fieldDelimiter;
}
/**
* @return the fieldDelimiter
*/
public char getFieldDelimiter() {
return fieldDelimiter;
}
/**
* @param textDelimiter
* the textDelimiter to set
*/
public void setTextDelimiter(char textDelimiter) {
this.textDelimiter = textDelimiter;
}
/**
* @return the textDelimiter
*/
public char getTextDelimiter() {
return textDelimiter;
}
/**
* is ignored characters
* @param c
* @return
*/
public boolean isIgnored(char c) {
return Arrays.binarySearch(ignoreCharacters, c) >= 0;
}
}
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