FeedWriter.java

/*
 * The MIT License (MIT)
 *
 * Copyright (c) 2014 México Abierto
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *
 * For more information visit https://github.com/mxabierto/avisos.
*/
package mx.org.cedn.avisosconagua.engine;

import com.google.publicalerts.cap.Alert;
import com.google.publicalerts.cap.CapUtil;
import com.google.publicalerts.cap.CapXmlBuilder;
import com.sun.syndication.feed.synd.SyndContent;
import com.sun.syndication.feed.synd.SyndContentImpl;
import com.sun.syndication.feed.synd.SyndEntry;
import com.sun.syndication.feed.synd.SyndEntryImpl;
import com.sun.syndication.feed.synd.SyndFeed;
import com.sun.syndication.feed.synd.SyndFeedImpl;
import com.sun.syndication.io.FeedException;
import com.sun.syndication.io.SyndFeedOutput;
import java.text.ParseException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Date;
import java.util.List;
import mx.org.cedn.avisosconagua.util.Utils;
/**
 * Feed Writer implementation using Google's CAP library.
 * @author Hasdai Pacheco
 */
public class FeedWriter {
    private SyndFeed feed;
    private CapXmlBuilder builder;
    private List<Alert> alerts;

    /**
     * Creates a new instance of a FeedWriter.
     * @param feedType Type for the feed, must be in supported types, defaults to "atom_1.0".
     */
    public FeedWriter(String feedType) {
        initFeed(feedType,"","");
    }
    
    /**
     * Creates a new instance of a FeedWriter.
     * @param feedType Type for the feed, must be in supported types, defaults to "atom_1.0".
     * @param feedTitle Title for the feed.
     * @param feedAuthor Author of the feed.
     */
    public FeedWriter (String feedType, String feedTitle, String feedAuthor) {
        initFeed(feedType, feedTitle, feedAuthor);
    }
    
    /**
     * Initializes feed writer.
     * @param feedType Type for the feed, must be in supported types, defaults to "atom_1.0".
     * @param feedTitle Title for the feed.
     * @param feedAuthor Author of the feed.
     */
    private void initFeed(String feedType, String feedTitle, String feedAuthor) {
        builder = new CapXmlBuilder(2);
        alerts = new ArrayList<>();
        feed = new SyndFeedImpl();
        feed.setFeedType(feedType);
        feed.setTitle(feedTitle);
        feed.setAuthor(feedAuthor);
        feed.setUri("http://smn.cna.gob.mx/capalert");
    }
    
    /**
     * Sets the title of the feed.
     * @param title Title.
     */
    public void setTitle(String title) {
        feed.setTitle(title);
    }
    
    /**
     * Sets the URI of the feed.
     * @param uri The URI.
     */
    public void setURI(String uri) {
        feed.setUri(uri);
    }
    
    /**
     * Sets the author of the feed.
     * @param author The autor.
     */
    public void setAuthor(String author) {
        feed.setAuthor(author);
    }
    
    /**
     * Sets publish date of the feed.
     * @param date The publish date.
     */
    public void setPubDate(Date date) {
        feed.setPublishedDate(date);
    }
    
    /**
     * Sets the list of alerts to generate the feed.
     * @param alertList List of alerts to be included in the feed.
     */
    public void setAlertList(List<Alert> alertList) {
        alerts = alertList;
    }
    
    /**
     * Gets the list of alerts defined for this feed.
     * @return List of alerts in the feed.
     */
    public List<Alert> getAlertList() {
        return alerts;
    }
    
    /**
     * Adds a CAP Alert to the list of alerts of this feed.
     * @param alert Alert to add to the feed.
     * @return true if alert was added
     */
    public boolean addAlert(Alert alert) {
        return alerts.add(alert);
    }
    
    /**
     * Adds the provided alerts to the list of alerts for this feed.
     * @param allAlerts list of alerts to add
     * @return true if alerts were added
     */
    public boolean addAllAlerts(List<Alert> allAlerts) {
        return alerts.addAll(allAlerts);
    }
    
    /**
     * Gets the XML for the feed.
     * @return String containing the XML code for the feed.
     */
    public String getXML() {
        String ret = "";
        List<SyndEntry> entries = new ArrayList<>();
        for(Alert alert : alerts) {
            if (!alert.getInfoList().isEmpty()) {
                SyndEntry entry = new SyndEntryImpl();
                entry.setUri(alert.getIdentifier());
                entry.setTitle(alert.getInfo(0).getEvent());
                try {
                    entry.setUpdatedDate(Utils.isoformater.parse(alert.getSent()));
                } catch (ParseException ex) {

                }

                SyndContent cnt = new SyndContentImpl();
                cnt.setType("text/xml");
                cnt.setValue(CapUtil.stripXmlPreamble(builder.toXml(alert)));

                entry.setContents(Collections.singletonList(cnt));            
                entries.add(entry);
            }
        }
        feed.setEntries(entries);
        
        try {
            SyndFeedOutput sfo = new SyndFeedOutput();
            ret = sfo.outputString(feed);
        } catch (FeedException ex) {
            System.out.println("There was an exception writing feed contents");
        }
        
        return ret;
    }
}