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Open HTML to PDF is a CSS 2.1 renderer written in Java. This artifact contains the core rendering and layout code.
/*
* StylesheetFactoryImpl.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.context;
import java.io.IOException;
import java.io.Reader;
import java.util.logging.Level;
import com.openhtmltopdf.css.extend.StylesheetFactory;
import com.openhtmltopdf.css.parser.CSSErrorHandler;
import com.openhtmltopdf.css.parser.CSSParser;
import com.openhtmltopdf.css.sheet.Ruleset;
import com.openhtmltopdf.css.sheet.Stylesheet;
import com.openhtmltopdf.css.sheet.StylesheetInfo;
import com.openhtmltopdf.extend.UserAgentCallback;
import com.openhtmltopdf.resource.CSSResource;
import com.openhtmltopdf.util.XRLog;
/**
* A Factory class for Cascading Style Sheets. Sheets are parsed using a single
* parser instance for all sheets. Sheets are cached by URI using a LRU test,
* but timestamp of file is not checked.
*
* @author Torbjoern Gannholm
*/
public class StylesheetFactoryImpl implements StylesheetFactory {
/**
* the UserAgentCallback to resolve uris
*/
private UserAgentCallback _userAgentCallback;
private int _cacheCapacity = 16;
/**
* an LRU cache
*/
private java.util.LinkedHashMap _cache =
new java.util.LinkedHashMap(_cacheCapacity, 0.75f, true) {
private static final long serialVersionUID = 1L;
protected boolean removeEldestEntry(java.util.Map.Entry eldest) {
return size() > _cacheCapacity;
}
};
private CSSParser _cssParser;
public StylesheetFactoryImpl(UserAgentCallback userAgentCallback) {
_userAgentCallback = userAgentCallback;
_cssParser = new CSSParser(new CSSErrorHandler() {
public void error(String uri, String message) {
XRLog.cssParse(Level.WARNING, "(" + uri + ") " + message);
}
});
}
public synchronized Stylesheet parse(Reader reader, StylesheetInfo info) {
try {
return _cssParser.parseStylesheet(info.getUri(), info.getOrigin(), reader);
} catch (IOException e) {
XRLog.cssParse(Level.WARNING, "Couldn't parse stylesheet at URI " + info.getUri() + ": " + e.getMessage(), e);
e.printStackTrace();
return new Stylesheet(info.getUri(), info.getOrigin());
}
}
/**
* @return Returns null if uri could not be loaded
*/
private Stylesheet parse(StylesheetInfo info) {
CSSResource cr = _userAgentCallback.getCSSResource(info.getUri());
if (cr == null) {
return null;
}
Reader reader = cr.getResourceReader();
if (reader == null) {
return null;
}
try {
return parse(reader, info);
} finally {
try {
reader.close();
} catch (IOException e) {
// ignore
}
}
}
public synchronized Ruleset parseStyleDeclaration(int origin, String styleDeclaration) {
return _cssParser.parseDeclaration(origin, styleDeclaration);
}
/**
* Adds a stylesheet to the factory cache. Will overwrite older entry for
* same key.
*
* @param key Key to use to reference sheet later; must be unique in
* factory.
* @param sheet The sheet to cache.
*/
public synchronized void putStylesheet(Object key, Stylesheet sheet) {
_cache.put(key, sheet);
}
/**
* @param key
* @return true if a Stylesheet with this key has been put in the cache.
* Note that the Stylesheet may be null.
*/
//TODO: work out how to handle caching properly, with cache invalidation
public synchronized boolean containsStylesheet(Object key) {
return _cache.containsKey(key);
}
/**
* Returns a cached sheet by its key; null if no entry for that key.
*
* @param key The key for this sheet; same as key passed to
* putStylesheet();
* @return The stylesheet
*/
public synchronized Stylesheet getCachedStylesheet(Object key) {
return (Stylesheet) _cache.get(key);
}
/**
* Removes a cached sheet by its key.
*
* @param key The key for this sheet; same as key passed to
* putStylesheet();
*/
public synchronized Object removeCachedStylesheet(Object key) {
return _cache.remove(key);
}
public synchronized void flushCachedStylesheets() {
_cache.clear();
}
/**
* Returns a cached sheet by its key; loads and caches it if not in cache;
* null if not able to load
*
* @param info The StylesheetInfo for this sheet
* @return The stylesheet
*/
//TODO: this looks a bit odd
public Stylesheet getStylesheet(StylesheetInfo info) {
XRLog.load("Requesting stylesheet: " + info.getUri());
Stylesheet s = getCachedStylesheet(info.getUri());
if (s == null && !containsStylesheet(info.getUri())) {
s = parse(info);
putStylesheet(info.getUri(), s);
}
return s;
}
public void setUserAgentCallback(UserAgentCallback userAgent) {
_userAgentCallback = userAgent;
}
public void setSupportCMYKColors(boolean b) {
_cssParser.setSupportCMYKColors(b);
}
}