SalesForce Apex CSV Parser

gistfile1.java

/**
 * Used to read a delimited file.
 */
public class SSSCsvReader {
	private String delim = ',';
	// the input data
	private String[] buffer;
	
	public SSSCsvReader(String data){
		this.buffer = data.split('\n'); 
	}
	
	public SSSCsvReader(String data, String delim){
		this.buffer = data.split('\n'); 
		this.delim = delim;
	}
	
	/**
	 * Read and parse next available line.  Return null if end of stream.
	 */
	public String[] readLine(){
		if(buffer.size() == 0)
			return null;
		String line = this.buffer.remove(0);
		String[] parts = new String[] {};
		while(line != ''){
			Integer next = 0;
			if(line.startsWith('"')){
				line = line.substring(1); // strip initial
				Integer quoteIndex = findQuote(line, 0);
				while(quoteIndex == -1){
					if(buffer.size() == 0){
						// EOT!
						quoteIndex = line.length();
					} else { 
						// grab the next line
						Integer skip = line.length();
						line += '\n' + this.buffer.remove(0);
						quoteIndex = findQuote(line, skip);
					}
				}
				// advance to comma
				next = quoteIndex + 1;
				parts.add(line.substring(0, quoteIndex).replace('""', '"'));
			} else {
				next = line.indexOf(this.delim, next);
				if(next == -1)
					next = line.length();
				// NB in Substring, "endindex" is the index of the character AFTER the last index to get
				parts.add(line.substring(0, next));
			}		
			if(next == line.length() - 1)
				// case of a terminating comma.
				parts.add('');
			line = next < line.length() ? line.substring(next+1) : '';
		}
		if(parts.size() == 0)
			// empty string - we still want to return something...
			parts.add('');
		return parts;
	}
	
	static private Pattern quotePattern = Pattern.compile('(?<!")"(?!")');
	/**
	 * Find next quote in the line
	 */
	private Integer findQuote(String line, Integer skip){
		Matcher m = quotePattern.matcher(line);
		m.region(skip, m.regionEnd());
		if(!m.find())
			return -1;
		return m.start();
	}
}