CSVReader.java

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.nio.CharBuffer;
import java.util.ArrayList;
import java.util.Collections;
import java.util.LinkedList;
import java.util.List;

/**
 * Simple symbol CSV reader class.
 *
 * @author cab404
 */
public class CSVReader {
    private final static int INROW = 0;
    private final static int INSTRING = 1;
    private final static int ENDSTRING = 2;

    private List<List<String>> table = new LinkedList<List<String>>();
    private List<String> currentRow = new ArrayList<String>();
    private StringBuilder buff = new StringBuilder();
    private int state = 0;

    private final char textDelimeter;
    private final char rowDelimeter;
    private final char separator;

    public CSVReader(char separator, char textDelimeter) {
        this.textDelimeter = textDelimeter;
        this.rowDelimeter = '\n';
        this.separator = separator;
    }

    public CSVReader(char separator, char textDelimeter, char rowDelimeter) {
        this.textDelimeter = textDelimeter;
        this.rowDelimeter = rowDelimeter;
        this.separator = separator;
    }

    /**
     * Parses next chunk of data.
     */
    public void read(CharSequence sequence) {
        for (int i = 0; i < sequence.length(); i++) {
            char ch = sequence.charAt(i);
            switch (state) {
                case INROW:
                    if (ch == rowDelimeter) {
                        flushRow();
                        continue;
                    }
                    if (ch == textDelimeter) {
                        state = INSTRING;
                        continue;
                    }
                    if (ch == separator) {
                        flushCell();
                        continue;
                    }
                    buff.append(ch);
                    continue;
                case INSTRING:
                    if (ch == textDelimeter) {
                        state = ENDSTRING;
                        continue;
                    }
                    buff.append(ch);
                    continue;
                case ENDSTRING:
                    if (ch == rowDelimeter) {
                        flushRow();
                        continue;
                    }
                    if (ch == separator) {
                        flushCell();
                        continue;
                    }
                    if (ch == textDelimeter) {
                        state = INSTRING;
                        buff.append(textDelimeter);
                        continue;
                    }
                    continue;
            }
        }
    }

    private void flushCell() {
        state = INROW;
        currentRow.add(buff.toString());
        buff.setLength(0);
    }

    private void flushRow() {
        flushCell();
        table.add(Collections.unmodifiableList(currentRow));
        currentRow = new ArrayList<String>();
    }

    public List<List<String>> getTable() {
        return Collections.unmodifiableList(table);
    }

    public void read(Reader reader) throws IOException {
        CharBuffer buffer = CharBuffer.allocate(256);
        while (reader.read(buffer) != -1) {
            buffer.flip();
            read(buffer);
            buffer.clear();
        }
    }

    public void read(InputStream stream) throws IOException {
        read(new InputStreamReader(stream));
    }

}