FixedWidthFormat.java

/*
 * $Id: FixedWidthFormat.java,v 1.2 2005/12/19 12:31:29 oldman1004 Exp $
 *
 * Copyright(c) 2002 Infomata
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
package com.infomata.data;

import java.util.Iterator;

/**
 * Data file format that uses fixed width to define each item
 * per row of data.
 *
 * @author <a href="mailto:oldman1004@gmail.com">Sam Kim</a>
 * @version $Revision: 1.2 $
 */
public class FixedWidthFormat implements DataFormat {

    /**
     * Creates a new <code>FixedWidthFormat</code> instance.
     *
     * @param widths list of width of each item contained in
     *               data file in correct order.
     */
    public FixedWidthFormat(int[] widths) {

        beg = new int[widths.length];
        width = new int[widths.length];

        System.arraycopy(widths, 0, width, 0, widths.length);
        System.arraycopy(widths, 0, beg, 1, widths.length - 1);

        if (beg.length > 2) {
            for (int i = 2; i < beg.length; i++) {
                beg[i] += beg[i - 1];
            }
        }
    }

    /**
     * Parses a line of text containing
     * data contained according to pre-defined character widths.
     *
     * @param line <code>String</code> object containing data.
     * @return <code>DataRow</code> object containing data parsed
     *         from <code>line</code>.
     */
    public DataRow parseLine(String line) {

        DataRow row = null;

        if (line != null) {
            row = new DataRow();
            for (int i = 0; i < width.length; i++) {
                if (i == width.length - 1) {
                    row.add(line.substring(beg[i]).trim());
                }
                else {
                    String val = line.substring(beg[i], beg[i + 1]);
                    row.add(val.trim());
                }
            }
        }

        return row;
    }

    /**
     * Formats the data contained in <code>DataRow</code> object
     * into a <code>String</code> according to pre-defined
     * widths.
     *
     * @param row <code>DataRow</code> containing data to be written
     *            to file.
     * @return line of text containing data in specified widths.
     */
    public String format(DataRow row) {

        StringBuffer o = new StringBuffer();
        Iterator i = row.iterator();
        int cnt = 0;

        while (i.hasNext() && cnt < beg.length) {

            String c = (String)i.next();

            int diff = width[cnt] - c.length();

            if (diff > 0) {
                o.append(c);
                for (int j = 0; j < diff; j++) {
                    o.append(SPACE);
                }
            }
            else if (diff < 0) {
                o.append(c.substring(0, width[cnt]));
            }
            else {
                o.append(c);
            }

            cnt++;

        }

        return o.toString();

    }

    private int[] beg = null;
    private int[] width = null;
    private static final char SPACE = ' ';

} // class FixedWidthFormat