1 /*

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

     3  *

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

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

     6  * published by the Free Software Foundation.  Oracle designates this

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

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

     9  *

    10  * This code is distributed in the hope that it will be useful, but WITHOUT

    11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

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

    14  * accompanied this code).

    15  *

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

    17  * 2 along with this work; if not, write to the Free Software Foundation,

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

    19  *

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

    21  * or visit www.oracle.com if you need additional information or have any

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    24 /*

    25  * Copyright (c) 2015 World Wide Web Consortium,

    26  *

    27  * (Massachusetts Institute of Technology, European Research Consortium for

    28  * Informatics and Mathematics, Keio University, Beihang). All Rights Reserved.

    29  * This work is distributed under the W3C(r) Software License [1] in the hope that

    30  * it will be useful, but WITHOUT ANY WARRANTY; without even the implied

    31  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

    32  *

    33  * [1] http://www.w3.org/Consortium/Legal/copyright-software

    34  */

    35 

    36 package org.w3c.dom;

    37 

    38 /**

    39  * The {@code ElementTraversal} interface is a set of read-only attributes

    40  * which allow an author to easily navigate between elements in a document.

    41  * <p>

    42  * In conforming implementations of Element Traversal, all objects that

    43  * implement {@link Element} must also implement the {@code ElementTraversal}

    44  * interface. Four of the methods,

    45  * {@link #getFirstElementChild}, {@link #getLastElementChild},

    46  * {@link #getPreviousElementSibling}, and {@link #getNextElementSibling},

    47  * each provides a live reference to another element with the defined

    48  * relationship to the current element, if the related element exists. The

    49  * fifth method, {@link #getChildElementCount}, exposes the number of child

    50  * elements of an element, for preprocessing before navigation.

    51  *

    52  * @see

    53  * <a href='http://www.w3.org/TR/ElementTraversal/'><cite>Element Traversal Specification</cite></a>.

    54  *

    55  * @since 9

    56  */

    57 public interface ElementTraversal {

    58 

    59     /**

    60      * Returns a reference to the first child node of the element which is of

    61      * the {@link Element} type.

    62      *

    63      * @return a reference to an element child, {@code null} if the element has

    64      * no child of the {@link Element} type.

    65      */

    66     Element getFirstElementChild();

    67 

    68     /**

    69      * Returns a reference to the last child node of the element which is of

    70      * the {@link Element} type.

    71      *

    72      * @return a reference to an element child, {@code null} if the element has

    73      * no child of the {@link Element} type.

    74      */

    75     Element getLastElementChild();

    76 

    77     /**

    78      * Returns a reference to the sibling node of the element which most immediately

    79      * precedes the element in document order, and which is of the {@link Element} type.

    80      *

    81      * @return a reference to an element child, {@code null} if the element has

    82      * no sibling node of the {@link Element} type that comes before this one.

    83      */

    84     Element getPreviousElementSibling();

    85 

    86     /**

    87      * Returns a reference to the sibling node of the element which most immediately

    88      * follows the element in document order, and which is of the {@link Element} type.

    89      *

    90      * @return a reference to an element child, {@code null} if the element has

    91      * no sibling node of the {@link Element} type that comes after this one.

    92      */

    93     Element getNextElementSibling();

    94 

    95     /**

    96      * Returns the current number of child nodes of the element which are of

    97      * the {@link Element} type.

    98      *

    99      * @return the number of element children, or {@code 0} if the element has

   100      * no element children.

   101      */

   102     int getChildElementCount();

   103 }