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/*
* DelegatingUserAgent.java
* Copyright (c) 2004, 2005 Torbjoern Gannholm
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation; either version 2.1
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
*/
package org.xhtmlrenderer.swing;
import com.google.errorprone.annotations.CheckReturnValue;
import org.jspecify.annotations.Nullable;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.xhtmlrenderer.event.DocumentListener;
import org.xhtmlrenderer.extend.UserAgentCallback;
import org.xhtmlrenderer.resource.CSSResource;
import org.xhtmlrenderer.resource.ImageResource;
import org.xhtmlrenderer.resource.XMLResource;
import org.xhtmlrenderer.util.IOUtil;
import java.io.IOException;
import java.io.InputStream;
/**
* NaiveUserAgent is a simple implementation of {@link org.xhtmlrenderer.extend.UserAgentCallback} which places no restrictions on what
* XML, CSS or images are loaded, and reports visited links without any filtering. The most straightforward process
* available in the JDK is used to load the resources in question--either using java.io or java.net classes.
*
*
The NaiveUserAgent has a small cache for images,
* the size of which (number of images) can be passed as a constructor argument. There is no automatic cleaning of
* the cache; call {@link #shrinkImageCache()} to remove the least-accessed elements--for example, you might do this
* when a new document is about to be loaded. The NaiveUserAgent is also a DocumentListener; if registered with a
* source of document events (like the panel hierarchy), it will respond to the
* {@link org.xhtmlrenderer.event.DocumentListener#documentStarted()} call and attempt to shrink its cache.
*
*
This class is meant as a starting point--it will work out of the box, but you should really implement your
* own, tuned to your application's needs.
*
* @author Torbjoern Gannholm
*/
public class DelegatingUserAgent implements UserAgentCallback, DocumentListener {
private static final Logger log = LoggerFactory.getLogger(DelegatingUserAgent.class);
private final UriResolver _uriResolver = new UriResolver();
private ImageResourceLoader _imageResourceLoader;
/**
* Creates a new instance of NaiveUserAgent with a max image cache of 16 images.
*/
public DelegatingUserAgent() {
this(new ImageResourceLoader());
}
public DelegatingUserAgent(ImageResourceLoader imageResourceLoader) {
_imageResourceLoader = imageResourceLoader;
}
/**
* @deprecated Pass loader right to the constructor (instead of using setter)
*/
@Deprecated
public void setImageResourceLoader(ImageResourceLoader loader) {
_imageResourceLoader = loader;
}
/**
* If the image cache has more items than the limit specified for this class, the least-recently used will
* be dropped from cache until it reaches the desired size.
*/
public void shrinkImageCache() {
_imageResourceLoader.shrink();
}
/**
* Empties the image cache entirely.
*/
public void clearImageCache() {
_imageResourceLoader.clear();
}
/**
* Gets a Reader for the resource identified
*/
@CheckReturnValue
@Nullable
protected InputStream resolveAndOpenStream(String uri) {
return IOUtil.openStreamAtUrl(_uriResolver.resolve(uri));
}
/**
* Retrieves the CSS located at the given URI. It's assumed the URI does point to a CSS file--the URI will
* be accessed (using java.io or java.net), opened, read and then passed into the CSS parser.
* The result is packed up into an CSSResource for later consumption.
*
* @param uri Location of the CSS source.
* @return A CSSResource containing the parsed CSS.
*/
@Override
@CheckReturnValue
public CSSResource getCSSResource(String uri) {
return new CSSResource(resolveAndOpenStream(uri));
}
/**
* Retrieves the image located at the given URI. It's assumed the URI does point to an image--the URI will
* be accessed (using java.io or java.net), opened, read and then passed into the JDK image-parsing routines.
* The result is packed up into an ImageResource for later consumption.
*
* @param uri Location of the image source.
* @return An ImageResource containing the image.
*/
@Override
@CheckReturnValue
public ImageResource getImageResource(String uri) {
return _imageResourceLoader.get(resolveURI(uri));
}
/**
* Retrieves the XML located at the given URI. It's assumed the URI does point to XML--the URI will
* be accessed (using java.io or java.net), opened, read and then passed into the XML parser (XMLReader)
* configured for Flying Saucer. The result is packed up into an XMLResource for later consumption.
*
* @param uri Location of the XML source.
* @return An XMLResource containing the image.
*/
@CheckReturnValue
@Nullable
@Override
public XMLResource getXMLResource(String uri) {
String resolvedUri = _uriResolver.resolve(uri);
try (InputStream in = IOUtil.getInputStream(resolvedUri)) {
return XMLResource.load(in);
} catch (IOException e) {
log.warn("Failed to load XML resource from {}", resolvedUri, e);
return null;
}
}
@CheckReturnValue
@Override
public byte @Nullable [] getBinaryResource(String uri) {
String resolvedUri = _uriResolver.resolve(uri);
return IOUtil.readBytes(resolvedUri);
}
/**
* Returns true if the given URI was visited, meaning it was requested at some point since initialization.
*
* @param uri A URI which might have been visited.
* @return Always false; visits are not tracked in the NaiveUserAgent.
*/
@Override
public boolean isVisited(@Nullable String uri) {
return false;
}
/**
* URL relative to which URIs are resolved.
*
* @param uri A URI which anchors other, possibly relative URIs.
*/
@Override
public void setBaseURL(@Nullable String uri) {
_uriResolver.setBaseUri(uri);
}
/**
* Resolves the URI; if absolute, leaves as is, if relative, returns an absolute URI based on the baseUrl for
* the agent.
*
* @param uri A URI, possibly relative.
* @return A URI as String, resolved, or null if there was an exception (for example if the URI is malformed).
*/
@Nullable
@CheckReturnValue
@Override
public String resolveURI(@Nullable String uri) {
return _uriResolver.resolve(uri);
}
/**
* Returns the current baseUrl for this class.
*/
@CheckReturnValue
@Nullable
@Override
public String getBaseURL() {
return _uriResolver.getBaseUri();
}
@Override
public void documentStarted() {
_imageResourceLoader.stopLoading();
shrinkImageCache();
}
@Override
public void documentLoaded() { /* ignore*/ }
@Override
public void onLayoutException(Throwable t) { /* ignore*/ }
@Override
public void onRenderException(Throwable t) { /* ignore*/ }
public void setRepaintListener(RepaintListener listener) {
//_imageResourceLoader.setRepaintListener(listener);
}
}