1 #// Usage: jjs -scripting jsadapter_dom.js

     2 

     3 /*

     4  * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.

     5  *

     6  * Redistribution and use in source and binary forms, with or without

     7  * modification, are permitted provided that the following conditions

     8  * are met:

     9  *

    10  *   - Redistributions of source code must retain the above copyright

    11  *     notice, this list of conditions and the following disclaimer.

    12  *

    13  *   - Redistributions in binary form must reproduce the above copyright

    14  *     notice, this list of conditions and the following disclaimer in the

    15  *     documentation and/or other materials provided with the distribution.

    16  *

    17  *   - Neither the name of Oracle nor the names of its

    18  *     contributors may be used to endorse or promote products derived

    19  *     from this software without specific prior written permission.

    20  *

    21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS

    22  * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,

    23  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

    24  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR

    25  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,

    26  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

    27  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR

    28  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF

    29  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING

    30  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS

    31  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

    32  */

    33 

    34 // Simple example that demonstrates reading XML Rss feed

    35 // to generate a HTML file from script and show it by browser

    36 // Uses XML DOM parser and DOM element wrapped by script

    37 // "proxy" (JSAdapter constructor)

    38 

    39 // Java classes used

    40 var DocBuilderFac = Java.type("javax.xml.parsers.DocumentBuilderFactory");

    41 var Node = Java.type("org.w3c.dom.Node");

    42 var File = Java.type("java.io.File");

    43 var FileWriter = Java.type("java.io.FileWriter");

    44 var PrintWriter = Java.type("java.io.PrintWriter");

    45 

    46 // constants from Node class

    47 var ELEMENT_NODE = Node.ELEMENT_NODE;

    48 var TEXT_NODE = Node.TEXT_NODE;

    49 

    50 // parse XML from uri and return Document

    51 function parseXML(uri) {

    52     var docBuilder = DocBuilderFac.newInstance().newDocumentBuilder();

    53     return docBuilder["parse(java.lang.String)"](uri);

    54 }

    55 

    56 // get child Elements of given name of the parent element given

    57 function getChildElements(elem, name) {

    58     var nodeList = elem.childNodes;

    59     var childElems = [];

    60     var len = nodeList.length;

    61     for (var i = 0; i < len; i++) {

    62         var node = nodeList.item(i);

    63         if (node.nodeType == ELEMENT_NODE &&

    64             node.tagName == name) {

    65             childElems.push(wrapElement(node));

    66         }

    67     }

    68 

    69     return childElems;

    70 }

    71 

    72 // get concatenated child text content of an Element

    73 function getElemText(elem) {

    74     var nodeList = elem.childNodes;

    75     var len = nodeList.length;

    76     var text = '';

    77     for (var i = 0; i < len; i++) {

    78         var node = nodeList.item(i);

    79         if (node.nodeType == TEXT_NODE) {

    80             text += node.nodeValue;

    81         }

    82     }

    83 

    84     return text;

    85 }

    86 

    87 // Wrap DOM Element object as a convenient script object

    88 // using JSAdapter. JSAdapter is like java.lang.reflect.Proxy

    89 // in that it allows property access, method calls be trapped

    90 // by 'magic' methods like __get__, __call__.

    91 function wrapElement(elem) {

    92     if (! elem) {

    93         return elem;

    94     }

    95     return new JSAdapter() {

    96         // getter to expose child elements and attributes by name

    97         __get__: function(name) {

    98             if (typeof name == 'string') {

    99                 if (name.startsWith('@')) {

   100                     var attr = elem.getAttributeNode(name.substring(1));

   101                     return !attr? undefined : attr.value;

   102                 }

   103 

   104                 var arr = getChildElements(elem, name);

   105                 if (arr.length == 1) {

   106                     // single child element, expose as single element

   107                     return arr[0];

   108                 } else {

   109                     // multiple children of given name, expose as array

   110                     return arr;

   111                 }

   112             }

   113             return undefined;

   114         },

   115 

   116         __call__: function(name) {

   117             // toString override to get text content of this Element

   118             if (name == 'toString' || name == 'valueOf') {

   119                 return getElemText(elem);

   120             }

   121             return undefined;

   122         }

   123     }

   124 }

   125 

   126 // generate HTML using here-doc and string interpolation

   127 function getBooksHtml() {

   128     var doc = parseXML("http://www.gutenberg.org/cache/epub/feeds/today.rss");

   129     // wrap document root Element as script convenient object

   130     var rss = wrapElement(doc.documentElement);

   131     print("rss file version " + rss['@version']);

   132 

   133     var str = <<HEAD

   134 

   135 <html>

   136 <title>${rss.channel.title}</title>

   137 <body>

   138 <h1>${rss.channel.description}</h1>

   139 <p>

   140 Published on ${rss.channel.pubDate}

   141 </p>

   142 

   143 HEAD

   144 

   145     var items = rss.channel.item;

   146     for each (var i in items) {

   147         str += <<LIST

   148 

   149 <dl>

   150 <dt><a href="${i.link}">${i.title}</a></dt>

   151 <dd>${i.description}</dd>

   152 </dl>

   153 

   154 LIST

   155     }

   156     str += <<END

   157 

   158 </body>

   159 </html>

   160 

   161 END

   162     return str;

   163 }

   164 

   165 // write the string to the given file

   166 function writeTo(file, str) {

   167     var w = new PrintWriter(new FileWriter(file));

   168     try {

   169         w.print(str);

   170     } finally {

   171         w.close();

   172     }

   173 }

   174 

   175 // generate books HTML

   176 var str = getBooksHtml();

   177 

   178 // write to file. __DIR__ is directory where

   179 // this script is stored.

   180 var file = new File(__DIR__ + "books.html");

   181 writeTo(file, str);

   182 

   183 // show it by desktop browser

   184 try {

   185     var Desktop = Java.type("java.awt.Desktop");

   186     Desktop.desktop.browse(file.toURI());

   187 } catch (e) {

   188     print(e);

   189 }