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/*
* This file is part of the Echo Web Application Framework (hereinafter "Echo").
* Copyright (C) 2002-2009 NextApp, Inc.
*
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*/
package nextapp.echo2.app.componentxml;
import java.io.IOException;
import java.io.InputStream;
import java.util.HashMap;
import java.util.Map;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import nextapp.echo2.app.DerivedMutableStyle;
import nextapp.echo2.app.MutableStyleSheet;
import nextapp.echo2.app.Style;
import nextapp.echo2.app.StyleSheet;
import nextapp.echo2.app.util.DomUtil;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.xml.sax.EntityResolver;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
/**
* Loads XML style sheets.
*/
public class StyleSheetLoader {
/**
* Parses an XML style sheet and returns a StyleSheet
* instance.
*
* Styles for components that cannot be loaded by the specified
* ClassLoader will be ignored.
*
* @param resourceName the name of the resource on the
* CLASSPATH containing the XML data
* @param classLoader the ClassLoader with which to
* instantiate property objects
* @return the created StyleSheet or null if the resource
* does not exist
* @throws ComponentXmlException if parsing/instantiation errors occur
*/
public static StyleSheet load(String resourceName, ClassLoader classLoader)
throws ComponentXmlException {
InputStream in = null;
try {
in = classLoader.getResourceAsStream(resourceName);
if (in == null) {
return null;
}
return load(in, classLoader);
} finally {
if (in != null) { try { in.close(); } catch (IOException ex) { } }
}
}
/**
* Parses an XML style sheet and returns a StyleSheet
* instance.
*
* Styles for components that cannot be loaded by the specified
* ClassLoader will be ignored.
*
* @param in the InputStream containing the XML data
* @param classLoader the ClassLoader with which to
* instantiate property objects
* @return the created StyleSheet
* @throws ComponentXmlException if parsing/instantiation errors occur
*/
public static StyleSheet load(InputStream in, ClassLoader classLoader)
throws ComponentXmlException {
Document document;
try {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
factory.setNamespaceAware(true);
DocumentBuilder builder = factory.newDocumentBuilder();
builder.setEntityResolver(new EntityResolver() {
public InputSource resolveEntity(String publicId, String systemId)
throws SAXException, IOException {
throw new SAXException("External entities not supported.");
}
});
document = builder.parse(in);
} catch (IOException ex) {
throw new ComponentXmlException("Failed to parse InputStream.", ex);
} catch (ParserConfigurationException ex) {
throw new ComponentXmlException("Failed to parse InputStream.", ex);
} catch (SAXException ex) {
throw new ComponentXmlException("Failed to parse InputStream.", ex);
}
PropertyLoader propertyLoader = PropertyLoader.forClassLoader(classLoader);
Map namedStyleMap = new HashMap();
MutableStyleSheet styleSheet = new MutableStyleSheet();
Element styleSheetElement = document.getDocumentElement();
Element[] styleElements = DomUtil.getChildElementsByTagName(styleSheetElement, "style");
// First pass, load style information.
for (int i = 0; i < styleElements.length; ++i) {
String name = styleElements[i].getAttribute("name");
if (!styleElements[i].hasAttribute("type")) {
throw new ComponentXmlException("Component type not specified in style: " + name, null);
}
String type = styleElements[i].getAttribute("type");
Class componentClass;
try {
componentClass = Class.forName(type, true, classLoader);
} catch (ClassNotFoundException ex) {
// StyleSheet contains reference to Component which does not exist in this ClassLoader,
// and thus should be ignored.
continue;
}
DerivedMutableStyle style = new DerivedMutableStyle();
Element propertiesElement = DomUtil.getChildElementByTagName(styleElements[i], "properties");
Style propertyStyle = propertyLoader.createStyle(propertiesElement, type);
style.addStyleContent(propertyStyle);
Map classToStyleMap = (Map) namedStyleMap.get(name);
if (classToStyleMap == null) {
classToStyleMap = new HashMap();
namedStyleMap.put(name, classToStyleMap);
}
classToStyleMap.put(componentClass, style);
styleSheet.addStyle(componentClass, name, style);
}
// Second pass, bind derived styles to base styles where applicable.
for (int i = 0; i < styleElements.length; ++i) {
if (styleElements[i].hasAttribute("base-name")) {
String name = styleElements[i].getAttribute("name");
String type = styleElements[i].getAttribute("type");
Class componentClass;
try {
componentClass = Class.forName(type, true, classLoader);
} catch (ClassNotFoundException ex) {
// StyleSheet contains reference to Component which does not exist in this ClassLoader,
// and thus should be ignored.
continue;
}
Map classToStyleMap = (Map) namedStyleMap.get(name);
DerivedMutableStyle style = (DerivedMutableStyle) classToStyleMap.get(componentClass);
String baseName = styleElements[i].getAttribute("base-name");
classToStyleMap = (Map) namedStyleMap.get(baseName);
if (classToStyleMap == null) {
throw new ComponentXmlException("Invalid base style name for style name " + name + ".", null);
}
Style baseStyle = (Style) classToStyleMap.get(componentClass);
while (baseStyle == null && componentClass != Object.class) {
componentClass = componentClass.getSuperclass();
baseStyle = (Style) classToStyleMap.get(componentClass);
}
if (baseStyle == null) {
throw new ComponentXmlException("Invalid base style name for style name " + name + ".", null);
}
style.setParentStyle(baseStyle);
}
}
return styleSheet;
}
}