package nl.siegmann.epublib.viewer;
import java.awt.Image;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Dictionary;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Map;
import javax.imageio.ImageIO;
import javax.swing.text.html.HTMLDocument;
import nl.siegmann.epublib.browsersupport.Navigator;
import nl.siegmann.epublib.domain.Book;
import nl.siegmann.epublib.domain.Resource;
import nl.siegmann.epublib.util.CollectionUtil;
import org.apache.commons.io.FilenameUtils;
import org.apache.commons.lang.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* This class is a trick to get the JEditorKit to load its images from the epub file instead of from the given url.
*
* This class is installed as the JEditorPane's image cache.
* Whenever it is requested an image it will try to load that image from the epub.
*
* Can be shared by multiple documents but can only be <em>used</em> by one document at the time because of the currentFolder issue.
*
* @author paul
*
*/
class ImageLoaderCache extends Dictionary<String, Image> {
public static final String IMAGE_URL_PREFIX = "http:/";
private static final Logger log = LoggerFactory.getLogger(ImageLoaderCache.class);
private Map<String, Image> cache = new HashMap<String, Image>();
private Book book;
private String currentFolder = "";
private Navigator navigator;
public ImageLoaderCache(Navigator navigator) {
this.navigator = navigator;
initBook(navigator.getBook());
}
public void initBook(Book book) {
if (book == null) {
return;
}
this.book = book;
cache.clear();
this.currentFolder = "";
}
public void setContextResource(Resource resource) {
if (resource == null) {
return;
}
if (StringUtils.isNotBlank(resource.getHref())) {
int lastSlashPos = resource.getHref().lastIndexOf('/');
if (lastSlashPos >= 0) {
this.currentFolder = resource.getHref().substring(0, lastSlashPos + 1);
}
}
}
public void initImageLoader(HTMLDocument document) {
try {
document.setBase(new URL(ImageLoaderCache.IMAGE_URL_PREFIX));
} catch (MalformedURLException e) {
log.error(e.getMessage());
}
setContextResource(navigator.getCurrentResource());
document.getDocumentProperties().put("imageCache", this);
}
private String getResourceHref(String requestUrl) {
String resourceHref = requestUrl.toString().substring(IMAGE_URL_PREFIX.length());
resourceHref = currentFolder + resourceHref;
resourceHref = FilenameUtils.normalize(resourceHref);
// normalize uses the SYSTEM_SEPARATOR, which on windows is a '\'
// replace with '/' to make it href '/'
resourceHref = resourceHref.replaceAll("\\\\", "/");
return resourceHref;
}
/**
* Create an Image from the data of the given resource.
*
* @param imageResource
* @return
*/
private Image createImage(Resource imageResource) {
Image result = null;
try {
result = ImageIO.read(imageResource.getInputStream());
} catch (IOException e) {
log.error(e.getMessage());
}
return result;
}
public Image get(Object key) {
if (book == null) {
return null;
}
String imageURL = key.toString();
// see if the image is already in the cache
Image result = cache.get(imageURL);
if (result != null) {
return result;
}
// get the image resource href
String resourceHref = getResourceHref(imageURL);
// find the image resource in the book resources
Resource imageResource = book.getResources().getByHref(resourceHref);
if (imageResource == null) {
return result;
}
// create an image from the resource and add it to the cache
result = createImage(imageResource);
if (result != null) {
cache.put(imageURL.toString(), result);
}
return result;
}
public int size() {
return cache.size();
}
public boolean isEmpty() {
return cache.isEmpty();
}
public Enumeration<String> keys() {
return CollectionUtil.createEnumerationFromIterator(cache.keySet().iterator());
}
public Enumeration<Image> elements() {
return CollectionUtil.createEnumerationFromIterator(cache.values().iterator());
}
public Image put(String key, Image value) {
return cache.put(key.toString(), (Image) value);
}
public Image remove(Object key) {
return cache.remove(key);
}
/**
* Clears the image cache.
*/
public void clear() {
cache.clear();
}
public String toString() {
return cache.toString();
}
}