aoqi@0: #// Usage: jjs -scripting gutenberg.js
aoqi@0: 
aoqi@0: /*
aoqi@0:  * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
aoqi@0:  * 
aoqi@0:  * Redistribution and use in source and binary forms, with or without
aoqi@0:  * modification, are permitted provided that the following conditions
aoqi@0:  * are met:
aoqi@0:  * 
aoqi@0:  *   - Redistributions of source code must retain the above copyright
aoqi@0:  *     notice, this list of conditions and the following disclaimer.
aoqi@0:  * 
aoqi@0:  *   - Redistributions in binary form must reproduce the above copyright
aoqi@0:  *     notice, this list of conditions and the following disclaimer in the
aoqi@0:  *     documentation and/or other materials provided with the distribution.
aoqi@0:  * 
aoqi@0:  *   - Neither the name of Oracle nor the names of its
aoqi@0:  *     contributors may be used to endorse or promote products derived
aoqi@0:  *     from this software without specific prior written permission.
aoqi@0:  * 
aoqi@0:  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
aoqi@0:  * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
aoqi@0:  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
aoqi@0:  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
aoqi@0:  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
aoqi@0:  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
aoqi@0:  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
aoqi@0:  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
aoqi@0:  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
aoqi@0:  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
aoqi@0:  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
aoqi@0:  */
aoqi@0: 
aoqi@0: // Simple example that demonstrates reading XML Rss feed
aoqi@0: // to generate a HTML file from script and show it by browser
aoqi@0: 
aoqi@0: // Java classes used
aoqi@0: var Characters = Java.type("javax.xml.stream.events.Characters");
aoqi@0: var Factory = Java.type("javax.xml.stream.XMLInputFactory");
aoqi@0: var File = Java.type("java.io.File");
aoqi@0: var FileWriter = Java.type("java.io.FileWriter");
aoqi@0: var PrintWriter = Java.type("java.io.PrintWriter");
aoqi@0: var URL = Java.type("java.net.URL");
aoqi@0: 
aoqi@0: // read Rss feed from a URL. Returns an array
aoqi@0: // of objects having only title and link properties
aoqi@0: function readRssFeed(url) {
aoqi@0:     var fac = Factory.newInstance();
aoqi@0:     var reader = fac.createXMLEventReader(url.openStream());
aoqi@0: 
aoqi@0:     // get text content from next event
aoqi@0:     function getChars() {
aoqi@0:         var result = "";
aoqi@0:         var e = reader.nextEvent();
aoqi@0:         if (e instanceof Characters) {
aoqi@0:             result = e.getData();
aoqi@0:         }
aoqi@0:         return result;
aoqi@0:     }
aoqi@0: 
aoqi@0:     var items = [];
aoqi@0:     var title, link;
aoqi@0:     var inItem = false;
aoqi@0:     while (reader.hasNext()) {
aoqi@0:         var evt = reader.nextEvent();
aoqi@0:         if (evt.isStartElement()) {
aoqi@0:             var local = evt.name.localPart;
aoqi@0:             if (local == "item") {
aoqi@0:                // capture title, description now
aoqi@0:                inItem = true;
aoqi@0:             }
aoqi@0:         
aoqi@0:             if (inItem) {
aoqi@0:                 switch (local) {
aoqi@0:                     case 'title':
aoqi@0:                         title = getChars();
aoqi@0:                         break;
aoqi@0:                     case 'link':
aoqi@0:                         link = getChars();
aoqi@0:                         break;
aoqi@0:                 }
aoqi@0:             }
aoqi@0:         } else if (evt.isEndElement()) {
aoqi@0:             var local = evt.name.localPart;
aoqi@0:             if (local == "item") {
aoqi@0:                 // one item done, save it in result array
aoqi@0:                 items.push({ title: title, link: link });
aoqi@0:                 inItem = false;
aoqi@0:             }
aoqi@0:         }
aoqi@0:     }
aoqi@0: 
aoqi@0:     return items;
aoqi@0: }
aoqi@0: 
aoqi@0: // generate simple HTML for an RSS feed
aoqi@0: function getBooksHtml() {
aoqi@0:     var url = new URL("http://www.gutenberg.org/cache/epub/feeds/today.rss");
aoqi@0:     var items = readRssFeed(url);
aoqi@0: 
aoqi@0:     var str = "<ul>";
aoqi@0: 
aoqi@0:     // Nashorn's string interpolation and heredoc
aoqi@0:     // support is very handy in generating text content
aoqi@0:     // that is filled with elements from runtime objects.
aoqi@0:     // We insert title and link in <li> elements here.
aoqi@0:     for each (i in items) {
aoqi@0:         str += <<EOF
aoqi@0: <li>
aoqi@0:     <a href="${i.link}">${i.title}</a>
aoqi@0: </li>
aoqi@0: EOF
aoqi@0:     }
aoqi@0:     str += "</ul>";
aoqi@0:     return str;
aoqi@0: }
aoqi@0: 
aoqi@0: // write the string to the given file
aoqi@0: function writeTo(file, str) {
aoqi@0:     var w = new PrintWriter(new FileWriter(file));
aoqi@0:     try {
aoqi@0:         w.print(str);
aoqi@0:     } finally {
aoqi@0:         w.close();
aoqi@0:     }
aoqi@0: }
aoqi@0: 
aoqi@0: // generate books HTML
aoqi@0: var str = getBooksHtml();
aoqi@0: 
aoqi@0: // write to file. __DIR__ is directory where
aoqi@0: // this script is stored.
aoqi@0: var file = new File(__DIR__ + "books.html");
aoqi@0: writeTo(file, str);
aoqi@0: 
aoqi@0: // show it by desktop browser
aoqi@0: try {
aoqi@0:     var Desktop = Java.type("java.awt.Desktop");
aoqi@0:     Desktop.desktop.browse(file.toURI());
aoqi@0: } catch (e) {
aoqi@0:     print(e);
aoqi@0: }