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/**
 * DataCleaner (community edition)
 * Copyright (C) 2014 Free Software Foundation, Inc.
 *
 * This copyrighted material is made available to anyone wishing to use, modify,
 * copy, or redistribute it subject to the terms and conditions of the GNU
 * Lesser General Public License, as published by the Free Software Foundation.
 *
 * 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 Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this distribution; if not, write to:
 * Free Software Foundation, Inc.
 * 51 Franklin Street, Fifth Floor
 * Boston, MA  02110-1301  USA
 */
package org.datacleaner.util;

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

/**
 * A {@link Document} used for holding a single character.
 */
public class SingleCharacterDocument extends PlainDocument {

    private static final long serialVersionUID = 1L;

    @Override
    public void insertString(final int offs, final String str, final AttributeSet a) throws BadLocationException {
        if (str == null) {
            return;
        }

        final String newText = getText(0, getLength()) + str;
        final int length = newText.length();

        if (length == 1) {
            super.insertString(offs, str, a);
        } else if (length == 2) {
            if ('\\' == newText.charAt(0)) {
                // 2 characters are only allowed if the first letter is a
                // backslash (escape char)
                super.insertString(offs, str, a);
            }
        }
    }
}