CSV_Modular_1

CSVProcessor

package com.detector;

import java.util.ArrayList;
import java.util.List;

public class CSVProcessor {
	final String doubleQuoteRegex = "^\"\".*";
	
	private String[] process(String buffer) {
		List<String> values = new ArrayList<String>();
		if (buffer == null || buffer.isEmpty()) {
			return values.toArray(new String[] {});
		}
		
		StreamIterator charToken = new StreamIterator();
		charToken.setBuffer(buffer);
		// initially set to false,
		boolean isDoubleQuoteSkip = false;
		while (charToken.hasNext()) {
			char ch = charToken.getNext();
			if (ch == '\"') {
				isDoubleQuoteSkip = doubleQuoteProcess(isDoubleQuoteSkip,charToken,values);
			} else if (isDoubleQuoteSkip != true && ch == ',') {
				values.add("");
			} else {
				add(values, ch);
			}
		}
		return values.toArray(new String[] {});
	}
	
	/**
	 * @param isDoubleQuoteSkip
	 * @param charToken
	 * @param values
	 * @return
	 */
	private boolean doubleQuoteProcess(boolean isDoubleQuoteSkip,StreamIterator charToken,List<String> values){
		if (isDoubleQuoteSkip
				&& charToken.currentString()
							.matches(doubleQuoteRegex)) {
			// add this values based on the basic rule
			// double quote is followed by double quote
			add(values, '"');
			// skip the next double quote
			charToken.getNext();
		}else{
			// true <-> false
			isDoubleQuoteSkip = !isDoubleQuoteSkip;
		}
		return isDoubleQuoteSkip;
	}
	
	public void add(List<String> values, char ch) {
		// intialization
		if (values.size() == 0) {
			values.add("");
		}
		
		// append values to existing data 
		values.set(values.size() - 1, values.get(values.size() - 1) + ch);
	}

	public String[] csvToText(String buffer) {
		return process(buffer);
	}

	public static void main(String[] args) {
		CSVProcessor csvProcessor = new CSVProcessor();
		String[] values = csvProcessor
				.csvToText("1999,Chevy,\"Venture \"\"Extended Edition, Very Large\"\"\",,5000.00");
		for (String val : values) {
			System.out.println(val);
		}
		System.out.println("**************");
		values = csvProcessor.csvToText("1996,Jeep,Grand Cherokee,\"MUST SELL!\nair, moon roof, loaded\",4799.00");
		
		for (String val : values) {
			System.out.println(val);
		}
	}
}

StreamIterator{

class StreamIterator{
	
	private char next;
	private char peek;
	private int counter = -1;
	private String buffer;
	
	/**
	 * @return the counter
	 */
	public int getCounter() {
		return counter;
	}
	/**
	 * @param counter the counter to set
	 */
	public void setCounter(int counter) {
		this.counter = counter;
	}
	/**
	 * @return the buffer
	 */
	public String getBuffer() {
		return buffer;
	}
	/**
	 * @param buffer the buffer to set
	 */
	public void setBuffer(String buffer) {
		this.buffer = buffer;
		counterReset();
	}
	
	public void counterReset(){
		counter = -1;
	}
	
	/**
	 * @return the next
	 */
	public char getNext() {
		processNext();
		return next;
	}
	/**
	 * @return the peek
	 */
	public char getPeek() {
		processPeek();
		return peek;
	}
	
	public void processNext(){
		try{
			next = buffer.charAt(++counter);
		}catch(ArrayIndexOutOfBoundsException e){
			next = '\0';
		}
	}
	
	public void processPeek(){
		try{
			peek = buffer.charAt(counter+1);
		}catch(ArrayIndexOutOfBoundsException e){
			peek = '\0';
		}
	}
	
	public boolean hasNext(){
		if(buffer == null) return false;
		return counter+1<buffer.length();
	}
	
	public String currentString(){
		return buffer.substring(counter);
	}
}