/*

 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code 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

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 */

package javax.swing.text;

/**

 * Represents a location within a document.  It is intended to abstract away

 * implementation details of the document and enable specification of

 * positions within the document that are capable of tracking of change as

 * the document is edited.

 * <p>

 * A {@code Position} object points at a location between two characters.

 * As the surrounding content is altered, the {@code Position} object

 * adjusts its offset automatically to reflect the changes. If content is

 * inserted or removed before the {@code Position} object's location, then the

 * {@code Position} increments or decrements its offset, respectively,

 * so as to point to the same location. If a portion of the document is removed

 * that contains a {@code Position}'s offset, then the {@code Position}'s

 * offset becomes that of the beginning of the removed region. For example, if

 * a {@code Position} has an offset of 5 and the region 2-10 is removed, then

 * the {@code Position}'s offset becomes 2.

 * <p>

 * {@code Position} with an offset of 0 is a special case. It never changes its

 * offset while document content is altered.

 *

 * @author  Timothy Prinzing

 */

public interface Position {

    /**

     * Fetches the current offset within the document.

     *

     * @return the offset >= 0

     */

    public int getOffset();

    /**

     * A typesafe enumeration to indicate bias to a position

     * in the model.  A position indicates a location between

     * two characters.  The bias can be used to indicate an

     * interest toward one of the two sides of the position

     * in boundary conditions where a simple offset is

     * ambiguous.

     */

    public static final class Bias {

        /**

         * Indicates to bias toward the next character

         * in the model.

         */

        public static final Bias Forward = new Bias("Forward");

        /**

         * Indicates a bias toward the previous character

         * in the model.

         */

        public static final Bias Backward = new Bias("Backward");

        /**

         * string representation

         */

        public String toString() {

            return name;

        }

        private Bias(String name) {

            this.name = name;

        }

        private String name;

    }

}