/*

 * 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;

/**

 * Interface to describe a structural piece of a document.  It

 * is intended to capture the spirit of an SGML element.

 *

 * @author  Timothy Prinzing

 */

public interface Element {

    /**

     * Fetches the document associated with this element.

     *

     * @return the document

     */

    public Document getDocument();

    /**

     * Fetches the parent element.  If the element is a root level

     * element returns <code>null</code>.

     *

     * @return the parent element

     */

    public Element getParentElement();

    /**

     * Fetches the name of the element.  If the element is used to

     * represent some type of structure, this would be the type

     * name.

     *

     * @return the element name

     */

    public String getName();

    /**

     * Fetches the collection of attributes this element contains.

     *

     * @return the attributes for the element

     */

    public AttributeSet getAttributes();

    /**

     * Fetches the offset from the beginning of the document

     * that this element begins at.  If this element has

     * children, this will be the offset of the first child.

     * As a document position, there is an implied forward bias.

     *

     * @return the starting offset >= 0 and < getEndOffset();

     * @see Document

     * @see AbstractDocument

     */

    public int getStartOffset();

    /**

     * Fetches the offset from the beginning of the document

     * that this element ends at.  If this element has

     * children, this will be the end offset of the last child.

     * As a document position, there is an implied backward bias.

     * <p>

     * All the default <code>Document</code> implementations

     * descend from <code>AbstractDocument</code>.

     * <code>AbstractDocument</code> models an implied break at the end of

     * the document. As a result of this, it is possible for this to

     * return a value greater than the length of the document.

     *

     * @return the ending offset > getStartOffset() and

     *     <= getDocument().getLength() + 1

     * @see Document

     * @see AbstractDocument

     */

    public int getEndOffset();

    /**

     * Gets the child element index closest to the given offset.

     * The offset is specified relative to the beginning of the

     * document.  Returns <code>-1</code> if the

     * <code>Element</code> is a leaf, otherwise returns

     * the index of the <code>Element</code> that best represents

     * the given location.  Returns <code>0</code> if the location

     * is less than the start offset. Returns

     * <code>getElementCount() - 1</code> if the location is

     * greater than or equal to the end offset.

     *

     * @param offset the specified offset >= 0

     * @return the element index >= 0

     */

    public int getElementIndex(int offset);

    /**

     * Gets the number of child elements contained by this element.

     * If this element is a leaf, a count of zero is returned.

     *

     * @return the number of child elements >= 0

     */

    public int getElementCount();

    /**

     * Fetches the child element at the given index.

     *

     * @param index the specified index >= 0

     * @return the child element

     */

    public Element getElement(int index);

    /**

     * Is this element a leaf element? An element that

     * <i>may</i> have children, even if it currently

     * has no children, would return <code>false</code>.

     *

     * @return true if a leaf element else false

     */

    public boolean isLeaf();

}