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Jython is an implementation of the high-level, dynamic, object-oriented language Python written in 100% Pure Java, and seamlessly integrated with the Java platform. It thus allows you to run Python on any Java platform.

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/*
 * Jython Database Specification API 2.0
 *
 *
 * Copyright (c) 2001 brian zimmer 
 *
 */
package com.ziclix.python.sql.pipe.csv;

import com.ziclix.python.sql.pipe.Sink;
import org.python.core.Py;
import org.python.core.PyObject;

import java.io.PrintWriter;

/**
 * The CSVSink writes data out in a Comma Seperated Format.
 *
 * @author brian zimmer
 */
public class CSVSink implements Sink {

    /**
     * Field header
     */
    protected boolean header;

    /**
     * Field delimiter
     */
    protected String delimiter;

    /**
     * Field writer
     */
    protected PrintWriter writer;

    /**
     * Field converters
     */
    protected PyObject converters;

    /**
     * All data will be written to the given PrintWriter.
     *
     * @param writer the PrintWriter to which data will be written
     */
    public CSVSink(PrintWriter writer) {
        this(writer, Py.None);
    }

    /**
     * All data will be written to the given PrintWriter.  If
     * the converters param is not None, then an attempt will
     * be made to convert the object using the given converter.
     *
     * @param writer     the PrintWriter to which data will be written
     * @param converters an indexed dictionary of callable objects used for converting objects to strings
     */
    public CSVSink(PrintWriter writer, PyObject converters) {

        this.header = false;
        this.writer = writer;
        this.converters = converters;
        this.delimiter = ",";
    }

    /**
     * Handle the data callback and write the row out.
     */
    public void row(PyObject row) {

        String[] values = new String[row.__len__()];

        if (this.header) {
            for (int i = 0; i < row.__len__(); i++) {
                values[i] = this.convert(Py.newInteger(i), row.__getitem__(i));
            }
        } else {
            for (int i = 0; i < row.__len__(); i++) {
                values[i] = row.__getitem__(i).__getitem__(0).toString();
            }

            this.header = true;
        }

        this.println(values);
    }

    /**
     * Convert the object at index to a String.
     */
    protected String convert(PyObject index, PyObject object) {

        if (this.converters != Py.None) {
            PyObject converter = this.converters.__finditem__(index);

            if (converter != Py.None) {
                object = converter.__call__(object);
            }
        }

        if ((object == Py.None) || (object == null)) {
            return "";
        }

        return CSVString.toCSV(object.toString());
    }

    /**
     * Print the row of Strings.
     */
    protected void println(String[] row) {

        for (int i = 0; i < row.length - 1; i++) {
            this.writer.print(row[i]);
            this.writer.print(this.delimiter);
        }

        this.writer.println(row[row.length - 1]);
    }

    /**
     * Method start
     */
    public void start() {
    }

    /**
     * Method end
     */
    public void end() {
    }
}