//
// Informa -- RSS Library for Java
// Copyright (c) 2002 by Niko Schmuck
//
// Niko Schmuck
// http://sourceforge.net/projects/informa
// mailto:niko_schmuck@users.sourceforge.net
//
// This library is free software.
//
// You may redistribute it and/or modify it under the terms of the GNU
// Lesser General Public License as published by the Free Software Foundation.
//
// Version 2.1 of the license should be included with this distribution in
// the file LICENSE. If the license is not included with this distribution,
// you may find a copy at the FSF web site at 'www.gnu.org' or 'www.fsf.org',
// or you may write to the Free Software Foundation, 675 Mass Ave, Cambridge,
// MA 02139 USA.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied waranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
// $Id: Channel.java,v 1.37 2006/12/04 23:43:27 italobb Exp $
package de.nava.informa.impl.hibernate;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Date;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.jdom.Element;
import de.nava.informa.core.CategoryIF;
import de.nava.informa.core.ChannelFormat;
import de.nava.informa.core.ChannelIF;
import de.nava.informa.core.ChannelObserverIF;
import de.nava.informa.core.ChannelUpdatePeriod;
import de.nava.informa.core.CloudIF;
import de.nava.informa.core.ImageIF;
import de.nava.informa.core.ItemIF;
import de.nava.informa.core.TextInputIF;
import de.nava.informa.utils.XmlPathUtils;
/**
* Hibernate implementation of the ChannelIF interface.
*
* @author Niko Schmuck (niko@nava.de)
*/
public class Channel implements ChannelIF {
private static Log logger = LogFactory.getLog(Channel.class);
private static final long serialVersionUID = 7579933431503905957L;
private long id = -1;
private String title;
private String description;
private URL location;
private URL site;
private String creator;
private String publisher;
private String language;
private ChannelFormat format;
private Set<ItemIF> items; // Items are ordered in RDF RSS 1.0.
private Set<ChannelGroup> groups;
private CloudIF cloud;
private ImageIF image;
private TextInputIF textInput;
private String copyright;
private Collection<CategoryIF> categories;
private Date lastUpdated;
private Date lastBuild;
private Date pubDate;
private String rating;
private String generator;
private String docs;
private int ttl = -1;
private Element channelElement;
// RSS 1.0 Syndication Module values
private ChannelUpdatePeriod updatePeriod = ChannelUpdatePeriod.UPDATE_DAILY;
private int updateFrequency = 1;
private Date updateBase;
private transient Collection<ChannelObserverIF> observers;
public Channel() {
this(null, null, null);
}
public Channel(String title) {
this(null, title, null);
}
public Channel(String title, String location) {
this(null, title, location);
}
public Channel(String title, URL location) {
this(null, title, location.toExternalForm());
}
public Channel(Element channelElement) {
this(channelElement, "Unnamed channel");
}
public Channel(Element channelElement, String title) {
this(channelElement, title, null);
}
public Channel(Element channelElement, String title, String location) {
this.channelElement = channelElement;
this.title = title;
setLocationString(location);
this.items = new HashSet<ItemIF>();
this.categories = new ArrayList<CategoryIF>();
this.observers = new ArrayList<ChannelObserverIF>();
this.groups = new HashSet<ChannelGroup>();
this.format = ChannelFormat.UNKNOWN_CHANNEL_FORMAT;
this.lastUpdated = new Date();
}
// --------------------------------------------------------------
// implementation of ChannelIF interface
// --------------------------------------------------------------
/**
* @return integer representation of identity.
*/
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
/**
* @return title.
*/
public String getTitle() {
return title;
}
public void setTitle(String aTitle) {
this.title = aTitle;
}
/**
* @return description.
*/
public String getDescription() {
return description;
}
public void setDescription(String aDescription) {
this.description = aDescription;
}
// We store the Location as a text string in the database, but as a URL in the memory based object.
// As far as Hibernate is concerned this is a STRING property. However the getter and setter
// convert to and from text for Informa.
/**
* @return location as a string.
*/
public String getLocationString() {
return (location == null) ? null : location.toString();
}
public void setLocationString(String loc) {
if (loc == null || loc.trim().length() == 0) {
location = null;
return;
} else {
try {
location = new URL(loc);
} catch (MalformedURLException e) {
logger.warn("Tried to set location to invalid URL", e);
location = null;
}
}
}
/**
* @return the location
*/
public URL getLocation() {
return location;
}
/**
* @param location the location to set
*/
public void setLocation(URL location) {
this.location = location;
}
/**
* @return URL of the site.
*/
public String getSiteString() {
return (site == null) ? null : site.toString();
}
public void setSiteString(String siteUrl) {
if (siteUrl == null || siteUrl.trim().length() == 0) {
site = null;
return;
} else {
try {
site = new URL(siteUrl);
} catch (MalformedURLException e) {
logger.warn("Tried to set site to invalid URL", e);
site = null;
}
}
}
public URL getSite() {
return site;
}
public void setSite(URL site) {
this.site = site;
}
/**
* @return name of creator.
*/
public String getCreator() {
return creator;
}
public void setCreator(String aCreator) {
this.creator = aCreator;
}
/**
* @return publisher.
*/
public String getPublisher() {
return publisher;
}
public void setPublisher(String aPublisher) {
this.publisher = aPublisher;
}
/**
* @return language of channel.
*/
public String getLanguage() {
return language;
}
public void setLanguage(String aLanguage) {
this.language = aLanguage;
}
/**
* @return format string.
*/
public String getFormatString() {
return format.toString();
}
public void setFormatString(String strFormat) {
// TODO: this could be improved by a format resolver
if (strFormat.equals(ChannelFormat.RSS_0_90.toString())) {
format = ChannelFormat.RSS_0_90;
} else if (strFormat.equals(ChannelFormat.RSS_0_91.toString())) {
format = ChannelFormat.RSS_0_91;
} else if (strFormat.equals(ChannelFormat.RSS_0_92.toString())) {
format = ChannelFormat.RSS_0_92;
} else if (strFormat.equals(ChannelFormat.RSS_0_93.toString())) {
format = ChannelFormat.RSS_0_93;
} else if (strFormat.equals(ChannelFormat.RSS_0_94.toString())) {
format = ChannelFormat.RSS_0_94;
} else if (strFormat.equals(ChannelFormat.RSS_1_0.toString())) {
format = ChannelFormat.RSS_1_0;
} else if (strFormat.equals(ChannelFormat.RSS_2_0.toString())) {
format = ChannelFormat.RSS_2_0;
}
}
public ChannelFormat getFormat() {
return format;
}
public void setFormat(ChannelFormat aFormat) {
this.format = aFormat;
}
/**
* @return set of groups.
*/
public Set<ChannelGroup> getGroups() {
return groups;
}
public void setGroups(Set<ChannelGroup> aGroups) {
this.groups = aGroups;
}
/**
* @return items of channel.
*/
public Set<ItemIF> getItems() {
return items;
}
public void setItems(Set<ItemIF> anItems) {
this.items = anItems;
}
public void addItem(ItemIF item) {
items.add(item);
item.setChannel(this);
notifyObserversItemAdded(item);
}
public void removeItem(ItemIF item) {
items.remove(item);
}
public ItemIF getItem(long itemId) {
// TODO: improve performance
// hibernate query cannot be used (not possible: no session object)
// may be use transient map: items.get(new Long(id));
ItemIF theItem = null;
Iterator it = items.iterator();
while (it.hasNext()) {
ItemIF curItem = (ItemIF) it.next();
if (curItem.getId() == itemId) {
theItem = curItem;
break;
}
}
return theItem;
}
/**
* @return image.
*/
public ImageIF getImage() {
return image;
}
public void setImage(ImageIF anImage) {
this.image = anImage;
}
/**
* @return text input.
*/
public TextInputIF getTextInput() {
return textInput;
}
public void setTextInput(TextInputIF aTextInput) {
this.textInput = aTextInput;
}
/**
* @return copyright note.
*/
public String getCopyright() {
return copyright;
}
public void setCopyright(String aCopyright) {
this.copyright = aCopyright;
}
/**
* @return rating.
*/
public String getRating() {
return rating;
}
public void setRating(String aRating) {
this.rating = aRating;
}
/**
* @return cloud.
*/
public CloudIF getCloud() {
return cloud;
}
public void setCloud(CloudIF aCloud) {
this.cloud = aCloud;
}
/**
* @return generator.
*/
public String getGenerator() {
return generator;
}
public void setGenerator(String aGenerator) {
this.generator = aGenerator;
}
/**
* @return docs.
*/
public String getDocs() {
return docs;
}
public void setDocs(String aDocs) {
this.docs = aDocs;
}
/**
* RSS 2.0: ttl stands for time to live. It's a number of minutes that
* indicates how long a channel can be cached before refreshing from
* the source
*
* @return TTL value.
*/
public int getTtl() {
return ttl;
}
public void setTtl(int aTtl) {
this.ttl = aTtl;
}
/**
* @return categories.
*/
public Collection getCategories() {
return categories;
}
public void setCategories(Collection<CategoryIF> aCategories) {
this.categories = aCategories;
}
public void addCategory(CategoryIF category) {
categories.add(category);
}
public void removeCategory(CategoryIF category) {
categories.remove(category);
}
/**
* @return date of last update.
*/
public Date getLastUpdated() {
return lastUpdated;
}
public void setLastUpdated(Date date) {
this.lastUpdated = date;
notifyObserversChannelUpdated();
}
/**
* RSS 0.91: The date-time the last time the content of the channel changed.
* RSS 2.0: The last time the content of the channel changed.
*
* @return date of last builing.
*/
public Date getLastBuildDate() {
return lastBuild;
}
public void setLastBuildDate(Date date) {
this.lastBuild = date;
}
/**
* @return publication date.
*/
public Date getPubDate() {
return pubDate;
}
public void setPubDate(Date date) {
this.pubDate = date;
}
// RSS 1.0 Syndication Module methods
/**
* @see de.nava.informa.core.ChannelIF#getUpdatePeriod()
*/
public ChannelUpdatePeriod getUpdatePeriod() {
return updatePeriod;
}
public void setUpdatePeriod(ChannelUpdatePeriod anUpdatePeriod) {
this.updatePeriod = anUpdatePeriod;
}
/**
* Accesses data provided by the Syndication module (will apply only
* to RSS 1.0+). Returns the number of times during the
* <code>updatePeriod</code> that a feed should be updated
* @return The number of times during <code>updatePeriod</code> to update the
* feed (the update frequency).
*/
public int getUpdateFrequency() {
return updateFrequency;
}
public void setUpdateFrequency(int anUpdateFrequency) {
this.updateFrequency = anUpdateFrequency;
}
/**
* @return update base.
*/
public Date getUpdateBase() {
return updateBase;
}
public void setUpdateBase(Date date) {
this.updateBase = date;
}
public String getElementValue(final String path) {
return XmlPathUtils.getElementValue(channelElement, path);
}
public String[] getElementValues(final String path, final String[] elements) {
return XmlPathUtils.getElementValues(channelElement, path, elements);
}
public String getAttributeValue(final String path, final String attribute) {
return XmlPathUtils.getAttributeValue(channelElement, path, attribute);
}
public String[] getAttributeValues(final String path,
final String[] attributes) {
return XmlPathUtils.getAttributeValues(channelElement, path, attributes);
}
// --------------------------------------------------------------
// implementation of ChannelObservableIF interface
// --------------------------------------------------------------
public void addObserver(ChannelObserverIF o) {
observers.add(o);
}
public void removeObserver(ChannelObserverIF o) {
observers.remove(o);
}
// --------------------------------------------------------------
// overwrite default method implementation from Object
// --------------------------------------------------------------
/**
* Returns a string representation of the object.
*
* @return a string representation of the object.
*/
public String toString() {
return "[Hibernate Channel (" + id + "): " + title + "("
+ getItems().size() + ")( " + location + " )]";
}
/**
* Compare two Channels for equality. Implementing this method and hashCode
* correctly is CRITICAL for Hibernate to function correctly. The semantic is
* that two Channels arensidered the 'same' RSS Channel. They may at one
* point in time have different values for different properties, but are
* they the SAME Channel? This is a very subtle Hibernate point, WHICH I
* AM 90% Sure I got right. In this case, two Channels are equal specifically
* if their RSS URL are the same. In other words, even if the title is
* different or the description is different, it's still the same Channel.
*
* @param o the reference object with which to compare.
*
* @return <code>true</code> if this object is the same as the obj
* argument; <code>false</code> otherwise.
*/
public boolean equals(Object o) {
if (this == o)
return true;
if (!(o instanceof ChannelIF))
return false;
final ChannelIF channel = (ChannelIF) o;
final String channelTitle = channel.getTitle();
if (title != null ? !title.equals(channelTitle) : channelTitle != null)
return false;
// Comparison of links uses synchronized code of Java-NET.
// This may hurt multi-threaded applications. So, please think twice
// before using direct comparison of links.
final URL channelLocation = channel.getLocation();
if (location != null ? channelLocation == null
|| !location.toString().equalsIgnoreCase(channelLocation.toString())
: channelLocation != null)
return false;
final String channelDescription = channel.getDescription();
if (description != null ? !description.equals(channelDescription)
: channelDescription != null)
return false;
return true;
}
/**
* Hashcode, like equals, is touchy and critical for proper functioning of
* Hibernate.
*
* @return a hash code value for this object.
*/
public int hashCode() {
return location.toString().hashCode();
}
/**
* Loops through and notifies each observer if a new item was
* detected.
*
* @param newItem item added.
*/
public void notifyObserversItemAdded(ItemIF newItem) {
Iterator it = observers.iterator();
while (it.hasNext()) {
ChannelObserverIF o = (ChannelObserverIF) it.next();
o.itemAdded(newItem);
}
}
/**
* Loops through and notifies each observer if a new item was
* detected.
*/
public void notifyObserversChannelUpdated() {
Iterator it = observers.iterator();
while (it.hasNext()) {
ChannelObserverIF o = (ChannelObserverIF) it.next();
o.channelRetrieved(this);
}
}
}