/*
 * File:     XNumericalJTextFieldFilter.java
 * Project:  MPI Linguistic Application
 * Date:     03 April 2006
 *
 * Copyright (C) 2001-2006  Max Planck Institute for Psycholinguistics
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package mpi.util.gui;

import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.PlainDocument;


/**
 * This class allows only integer resp float values to be entered or a +X or -X
 * (only upper case) standing for infinity
 */
public class XNumericalJTextFieldFilter extends PlainDocument {
    /** allow only positive integers */
    public static final int POS_INTEGER = 0;

    /** allow only zero and positive integers to be typed in */
    public static final int POS_INTEGER_WITH_INFINITY = 1;

    /** allow all integers to be typed in */
    public static final int INTEGER_WITH_INFINITY = 2;

    /** allow float numbers (using point as seperator) */
    public static final int FLOAT_WITH_INFINITY = 3;

    /** allow integers with positive but without negative infinity */
    public static final int INTEGER_WITH_POS_INFINITY = 4;

    /** allow integers with negative but without positive infinity */
    public static final int INTEGER_WITH_NEG_INFINITY = 5;

    /** all possible positive integer chars */
    protected static final String POS_INTEGER_CHARS = "+0123456789";

    /** Holds value of property DOCUMENT ME! */
    protected static final String POS_INTEGER_CHARS_WITH_INFINITY = POS_INTEGER_CHARS +
        "X";

    /** Holds value of property DOCUMENT ME! */
    protected static final String INTEGER_CHARS = "-" +
        POS_INTEGER_CHARS_WITH_INFINITY;

    /** Holds value of property DOCUMENT ME! */
    protected static final String FLOAT_CHARS = INTEGER_CHARS + ".";

    /** Holds value of property DOCUMENT ME! */
    protected String acceptedChars = null;
    private final int mode;

    /**
     * default setting to positive integers
     *
     * @see java.lang.Object#Object()
     */
    public XNumericalJTextFieldFilter() {
        mode = 0;
        acceptedChars = POS_INTEGER_CHARS_WITH_INFINITY;
    }

    /**
     * determines which characters may be typed in
     *
     * @param i
     */
    public XNumericalJTextFieldFilter(int mode) {
        this.mode = mode;

        switch (mode) {
        case POS_INTEGER_WITH_INFINITY:
            acceptedChars = INTEGER_CHARS;

            break;

        case FLOAT_WITH_INFINITY:
            acceptedChars = FLOAT_CHARS;

            break;

        case INTEGER_WITH_POS_INFINITY:
            acceptedChars = INTEGER_CHARS;

            break;

        case INTEGER_WITH_NEG_INFINITY:
            acceptedChars = INTEGER_CHARS;

            break;

        default:
            acceptedChars = POS_INTEGER_CHARS;
        }
    }

    /**
     * DOCUMENT ME!
     *
     * @param offset DOCUMENT ME!
     * @param str DOCUMENT ME!
     * @param attr DOCUMENT ME!
     *
     * @throws BadLocationException DOCUMENT ME!
     */
    public void insertString(int offset, String str, AttributeSet attr)
        throws BadLocationException {
        if (str == null) {
            return;
        }

        for (int i = 0; i < str.length(); i++) {
            if (acceptedChars.indexOf(str.charAt(i)) == -1) {
                return;
            }
        }

        if (acceptedChars.equals(FLOAT_CHARS)) {
            if (str.indexOf(".") != -1) {
                if (getText(0, getLength()).indexOf(".") != -1) {
                    return;
                }
            }
        }

        if (str.indexOf("-") != -1) {
            if ((str.indexOf("-") != 0) || (offset != 0)) {
                return;
            }
        }

        if (str.indexOf("+") != -1) {
            if ((str.indexOf("+") != 0) || (offset != 0)) {
                return;
            }
        }

        if ((getText(0, getLength()).indexOf('X') != -1) &&
                !((str.equals("+") && (mode != INTEGER_WITH_NEG_INFINITY)) ||
                (!str.equals("-") && (mode != INTEGER_WITH_POS_INFINITY)))) {
            return;
        }

        if (str.indexOf("X") != -1) {
            if (getLength() > 1) {
                return;
            }

            if (getLength() == 0) {
                if (!(((str.equals("+X") || str.equals("X")) &&
                        (mode != INTEGER_WITH_NEG_INFINITY)) ||
                        (str.equals("-X") &&
                        (mode != INTEGER_WITH_POS_INFINITY)))) {
                    return;
                }
            } else {
                if (!((getText(0, 1).equals("+") &&
                        (mode != INTEGER_WITH_NEG_INFINITY)) ||
                        (getText(0, 1).equals("-") &&
                        (mode != INTEGER_WITH_POS_INFINITY))) &&
                        str.equals("X")) {
                    return;
                }
            }
        }

        super.insertString(offset, str, attr);
    }
}
