Java tutorial
/* * See the NOTICE file distributed with this work for additional * information regarding copyright ownership. * * This 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 software 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 software; if not, write to the Free * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA * 02110-1301 USA, or see the FSF site: http://www.fsf.org. */ package org.xwiki.rendering.xdomxmlcurrent.internal.renderer; import java.lang.reflect.InvocationHandler; import java.lang.reflect.Method; import java.lang.reflect.Type; import java.util.Arrays; import java.util.List; import org.apache.commons.lang3.ObjectUtils; import org.xml.sax.Attributes; import org.xml.sax.ContentHandler; import org.xml.sax.SAXException; import org.xml.sax.helpers.AttributesImpl; import org.xwiki.component.util.ReflectionUtils; import org.xwiki.properties.ConverterManager; import org.xwiki.rendering.listener.descriptor.ListenerDescriptor; import org.xwiki.rendering.listener.descriptor.ListenerElement; import org.xwiki.rendering.xdomxmlcurrent.internal.XDOMXMLConstants; import org.xwiki.rendering.xdomxmlcurrent.internal.XDOMXMLCurrentUtils; import org.xwiki.rendering.xdomxmlcurrent.internal.parameter.ParameterManager; /** * Current version of the XDOM+XML stream based renderer. * * @version $Id: 838b86dae801884a4979ea6e63381af7af6f4ea9 $ */ public class XDOMXMLChainingStreamRenderer implements InvocationHandler { private ContentHandler contentHandler; private ParameterManager parameterManager; private ListenerDescriptor descriptor; private ConverterManager converter; public XDOMXMLChainingStreamRenderer(ParameterManager parameterManager, ListenerDescriptor descriptor, ConverterManager converter) { this.parameterManager = parameterManager; this.descriptor = descriptor; this.converter = converter; } private boolean isValidBlockElementName(String blockName) { return XDOMXMLConstants.VALID_ELEMENTNAME.matcher(blockName).matches() && !XDOMXMLConstants.ELEM_PARAMETER.equals(blockName); } private String getBlockName(String eventName, String prefix) { String blockName = eventName.substring(prefix.length()); blockName = Character.toLowerCase(blockName.charAt(0)) + blockName.substring(1); return blockName; } private void addInlineParameters(AttributesImpl attributes, List<Object> parameters, ListenerElement element) { for (int i = 0; i < parameters.size(); ++i) { Object parameter = parameters.get(i); if (parameter != null) { Type type = element.getParameters().get(i); Class<?> typeClass = ReflectionUtils.getTypeClass(type); if (XDOMXMLCurrentUtils.isSimpleType(typeClass)) { attributes.addAttribute(null, null, XDOMXMLConstants.ELEM_PARAMETER + i, null, this.converter.<String>convert(String.class, parameter)); parameters.set(i, null); } else if (ObjectUtils.equals(XDOMXMLCurrentUtils.defaultValue(typeClass), parameter)) { attributes.addAttribute(null, null, XDOMXMLConstants.ELEM_PARAMETER + i, null, ""); parameters.set(i, null); } } } } private AttributesImpl createStartAttributes(String blockName, List<Object> parameters) { AttributesImpl attributes = new AttributesImpl(); if (!isValidBlockElementName(blockName)) { attributes.addAttribute(null, null, XDOMXMLConstants.ATT_BLOCK_NAME, null, blockName); } if (parameters != null) { ListenerElement element = this.descriptor.getElements().get(blockName.toLowerCase()); addInlineParameters(attributes, parameters, element); } return attributes; } private void removeDefaultParameters(List<Object> parameters, ListenerElement descriptor) { if (parameters != null) { for (int i = 0; i < parameters.size(); ++i) { Object value = parameters.get(i); if (value != null && !shouldPrintParameter(value, i, descriptor)) { parameters.set(i, null); } } } } private void beginEvent(String eventName, Object[] parameters) { String blockName = getBlockName(eventName, "begin"); ListenerElement element = this.descriptor.getElements().get(blockName.toLowerCase()); List<Object> elementParameters = parameters != null ? Arrays.asList(parameters) : null; // Remove useless parameters removeDefaultParameters(elementParameters, element); // Put as attributes parameters which are simple enough to not require full XML serialization AttributesImpl attributes = createStartAttributes(blockName, elementParameters); // Get proper element name String elementName; if (isValidBlockElementName(blockName)) { elementName = blockName; } else { elementName = XDOMXMLConstants.ELEM_BLOCK; } // Print start element startElement(elementName, attributes); // Print complex parameters printParameters(elementParameters, element); } private void endEvent(String eventName) { String blockName = getBlockName(eventName, "end"); if (isValidBlockElementName(blockName)) { endElement(blockName); } else { endElement(XDOMXMLConstants.ELEM_BLOCK); } } private void onEvent(String eventName, Object[] parameters) { String blockName = getBlockName(eventName, "on"); ListenerElement element = this.descriptor.getElements().get(blockName.toLowerCase()); List<Object> elementParameters = parameters != null ? Arrays.asList(parameters) : null; // Remove useless parameters removeDefaultParameters(elementParameters, element); // Put as attributes parameters which are simple enough to not require full XML serialization AttributesImpl attributes = (elementParameters != null && elementParameters.size() > 1) ? createStartAttributes(blockName, Arrays.asList(parameters)) : new AttributesImpl(); // Get proper element name String elementName; if (isValidBlockElementName(blockName)) { elementName = blockName; } else { elementName = XDOMXMLConstants.ELEM_BLOCK; } // Print start element startElement(elementName, attributes); // Print complex parameters if (parameters != null && parameters.length == 1 && XDOMXMLCurrentUtils.isSimpleType(element.getParameters().get(0))) { String value = parameters[0].toString(); try { this.contentHandler.characters(value.toCharArray(), 0, value.length()); } catch (SAXException e) { throw new RuntimeException("Failed to send sax event", e); } } else { printParameters(elementParameters, element); } // Print end element endElement(elementName); } private boolean shouldPrintParameter(Object value, int index, ListenerElement descriptor) { boolean print = true; Type type = descriptor.getParameters().get(index); if (type instanceof Class) { Class<?> typeClass = (Class<?>) type; try { if (typeClass.isPrimitive()) { print = !XDOMXMLCurrentUtils.defaultValue(typeClass).equals(value); } } catch (Exception e) { // Should never happen } } return print; } private void printParameters(List<Object> parameters, ListenerElement descriptor) { if (parameters != null && !parameters.isEmpty()) { for (int i = 0; i < parameters.size(); ++i) { Object value = parameters.get(i); if (value != null && shouldPrintParameter(value, i, descriptor)) { startElement(XDOMXMLConstants.ELEM_PARAMETER + i); this.parameterManager.serialize(descriptor.getParameters().get(i), value, this.contentHandler); endElement(XDOMXMLConstants.ELEM_PARAMETER + i); } } } } private void startElement(String elemntName) { startElement(elemntName, (String[][]) null); } private void startElement(String elemntName, String[][] parameters) { startElement(elemntName, createAttributes(parameters)); } private void startElement(String elemntName, Attributes attributes) { try { this.contentHandler.startElement("", elemntName, elemntName, attributes); } catch (SAXException e) { throw new RuntimeException("Failed to send sax event", e); } } private void endElement(String elemntName) { try { this.contentHandler.endElement("", elemntName, elemntName); } catch (SAXException e) { throw new RuntimeException("Failed to send sax event", e); } } /** * Convert provided table into {@link Attributes} to use in xml writer. */ private Attributes createAttributes(String[][] parameters) { AttributesImpl attributes = new AttributesImpl(); if (parameters != null && parameters.length > 0) { for (String[] entry : parameters) { attributes.addAttribute(null, null, entry[0], null, entry[1]); } } return attributes; } @Override public Object invoke(Object proxy, Method method, Object[] args) throws Throwable { Object result = null; if (method.getName().equals("setContentHandler")) { this.contentHandler = (ContentHandler) args[0]; } else if (method.getName().equals("getContentHandler")) { result = this.contentHandler; } else if (method.getName().startsWith("begin")) { beginEvent(method.getName(), args); } else if (method.getName().startsWith("end")) { endEvent(method.getName()); } else if (method.getName().startsWith("on")) { onEvent(method.getName(), args); } else { throw new NoSuchMethodException(method.toGenericString()); } return result; } }