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/*
* UserAgentCallback.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 com.openhtmltopdf.extend;
import com.openhtmltopdf.resource.CSSResource;
import com.openhtmltopdf.resource.ImageResource;
import com.openhtmltopdf.resource.XMLResource;
/**
* To be implemented by any user agent using the panel. "User agent" is a
* term defined by the W3C in the documentation for XHTML and CSS; in most
* cases, you can think of this as the rendering component for a browser.
*
* This interface defines a simple callback mechanism for Flying Saucer to
* interact with a user agent. The FS toolkit provides a default implementation
* for this interface which in most cases you can leave as is.
*
* The user agent in this case is responsible for retrieving external resources. For
* privacy reasons, if using the library in an application that can access URIs
* in an unrestricted fashion, you may decide to restrict access to XML, CSS or images
* retrieved from external sources; that's one of the purposes of the UAC.
*
* To understand how to create your own UAC, it's best to look at some of the
* implemetations shipped with the library, like the {@link com.openhtmltopdf.swing.NaiveUserAgent}.
*
*
* @author Torbjoern Gannholm
*/
public interface UserAgentCallback {
/**
* Retrieves the CSS at the given URI. This is a synchronous call.
*
* @param uri Location of the CSS
* @return A CSSResource for the content at the URI.
*/
CSSResource getCSSResource(String uri);
/**
* Retrieves the Image at the given URI. This is a synchronous call.
*
* @param uri Location of the image
* @return An ImageResource for the content at the URI.
*/
ImageResource getImageResource(String uri);
/**
* Retrieves the XML at the given URI. This is a synchronous call.
*
* @param uri Location of the XML
* @return A XMLResource for the content at the URI.
*/
XMLResource getXMLResource(String uri);
/**
* Retrieves a binary resource located at a given URI and returns its contents
* as a byte array or null if the resource could not be loaded.
*/
byte[] getBinaryResource(String uri);
/**
* Normally, returns true if the user agent has visited this URI. UserAgent should consider
* if it should answer truthfully or not for privacy reasons.
*
* @param uri A URI which may have been visited by this user agent.
* @return The visited value
*/
boolean isVisited(String uri);
/**
* Does not need to be a correct URL, only an identifier that the
* implementation can resolve.
*
* @param url A URL against which relative references can be resolved.
*/
void setBaseURL(String url);
/**
* @return the base uri, possibly in the implementations private uri-space
*/
String getBaseURL();
/**
* Used to find a uri that may be relative to the BaseURL.
* The returned value will always only be used via methods in the same
* implementation of this interface, therefore may be a private uri-space.
*
* @param uri an absolute or relative (to baseURL) uri to be resolved.
* @return the full uri in uri-spaces known to the current implementation.
*/
String resolveURI(String uri);
String resolveUri(String baseUri, String uri);
}