TSTU-Student-App-Android/app/src/main/java/ru/defend/defdevteam/tstu/FeedParser.java

package ru.defend.defdevteam.tstu;

import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.xml.sax.Attributes;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.DefaultHandler;

import java.io.StringReader;
import java.util.ArrayList;
import java.util.Collection;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;

/**
 * Created by thedefend on 29.11.16.
 */

public class FeedParser {

    ParserCallback callback;
    String inputXML;

    interface ParserCallback {
        void onSuccessParsing();
        void onFailureParsing();
        void contentDispatcher(String title, String text, String link);
    }

    void registerCallback(ParserCallback callback) {
        this.callback = callback;
    }

    FeedParser(String inputXML) {
        this.inputXML = inputXML;
    }

//    static NewsItemList.Group parsedItem;
//    static void getParsedItem(String title, String description, String link, String date) {
//        parsedItem = new NewsItemList().new Group(title, description, date);
//        this.callback.contentDispatcher();
//    }

    void parseXML() {
        try {
            SAXParserFactory factory = SAXParserFactory.newInstance();
            SAXParser parser = factory.newSAXParser();
            ExtendedHandler handler = new ExtendedHandler();
            InputSource inputSource = new InputSource(new StringReader(inputXML));
            parser.parse(inputSource, handler);
        } catch (Exception e) {
            e.printStackTrace();
        }

    }

    public class ExtendedHandler extends DefaultHandler {
        boolean item = false;
        boolean title = false;
        boolean description = false;
        boolean link = false;
        boolean date = false;
        String titleStr;
        String descriptionStr;
        String linkStr;
        String dateStr;

        @Override
        public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
            if (qName.equalsIgnoreCase("item")) {
                item = true;
            }
            if (item) {
                String tagName = qName.toLowerCase();
                switch (tagName) {
                    case "title": title = true;
                        break;
                    case "description": description = true;
                        break;
                    case "link": link = true;
                        break;
                    case "date": date = true;
                }
            }
        }

        @Override
        public void characters(char ch[], int start, int length) throws SAXException {
            if(item) {
                if (title) {
                    titleStr = new String(ch, start, length);
                    title = false;
                } else if (description) {
                    descriptionStr = new String(ch, start, length);
                    description = false;
                } else if (link) {
                    linkStr = new String(ch, start, length);
                    link = false;
                } else if (date) {
                    dateStr = new String(ch, start, length);
                    date = false;
                }
            }
        }

        @Override
        public void endElement(String uri, String localName, String qName) throws SAXException {
            if (title) {
                title = false;
                return;
            } else if (description) {
                description = false;
                return;
            } else if (link) {
                link = false;
                return;
            } else if (date) {
                date = false;
                return;
            }
            if (item) {
                item = false;
                callback.contentDispatcher(titleStr, descriptionStr, "");
            }
        }

        @Override
        public void endDocument() throws SAXException {
                callback.onSuccessParsing();
        }
    }

}