/*

  * Copyright 2006-2011 The Kuali Foundation

  *

  * Licensed under the Educational Community License, Version 2.0 (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.opensource.org/licenses/ecl2.php

  *

  * Unless required by applicable law or agreed to in writing, software

  * distributed under the License is distributed on an "AS IS" BASIS,

  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

  * See the License for the specific language governing permissions and

  * limitations under the License.

  */

 package org.kuali.rice.kew.plugin;

 import org.apache.commons.lang.StringUtils;

 import org.jdom.Document;

 import org.jdom.Element;

 import org.jdom.JDOMException;

 import org.jdom.input.SAXBuilder;

 import org.kuali.rice.core.api.config.property.Config;

 import org.kuali.rice.core.xml.XmlException;

 import java.io.File;

 import java.io.IOException;

 import java.net.URL;

 import java.util.HashMap;

 import java.util.Iterator;

 import java.util.List;

 import java.util.Map;

 /**

  * Parses a {@link PluginConfig} configuration from an XML file.

  *

  * @author Kuali Rice Team (rice.collab@kuali.org)

  */

 public class PluginConfigParser {

     private static final String PARAMETER_TAG = "parameter";

     private static final String LISTENER_TAG = "listener";

     private static final String LISTENER_CLASS_TAG = "listener-class";

     private static final String RESOURCE_LOADER_TAG = "resourceLoader";

     private static final String NAME_ATTRIBUTE = "name";

     private static final String VALUE_ATTRIBUTE = "value";

     private static final String CLASS_ATTRIBUTE = "class";

     public PluginConfig parse(File configFile, Config parentConfig) throws IOException, XmlException {

             return parse(configFile.toURI().toURL(), parentConfig);

     }

         public PluginConfig parse(URL url, Config parentConfig) throws IOException, XmlException {

                 SAXBuilder builder = new SAXBuilder(false);

                 try {

             // NOTE: need to be wary of whether streams are closed properly

             // by builder

                         Document doc = builder.build(url);

                         Element root = doc.getRootElement();

                         PluginConfig pluginConfig = new PluginConfig(url, parentConfig);

                         parseResourceLoader(root, pluginConfig);

                         parseListeners(root, pluginConfig);

                         return pluginConfig;

                 } catch (JDOMException e) {

                     throw new PluginException("Error when parsing the plugin config file.", e);

                 }

         }

         public void parseResourceLoader(Element element, PluginConfig pluginConfig) throws XmlException {

                 List loaderElements = element.getChildren(RESOURCE_LOADER_TAG);

                 if (loaderElements.size() > 1) {

                         throw new XmlException("Only one <resourceLoader> tag may be defined.");

                 } else if (!loaderElements.isEmpty()) {

                         Element loaderElement = (Element)loaderElements.get(0);

                         String attributeClass = loaderElement.getAttributeValue(CLASS_ATTRIBUTE);

                         if (StringUtils.isEmpty(attributeClass)) {

                                 throw new XmlException("<resourceLoader> element must define a 'class' attribute.");

                         }

                         pluginConfig.setResourceLoaderClassname(attributeClass);

                 }

         }

         public void parseListeners(Element element, PluginConfig pluginConfig) throws XmlException {

                 List listeners = element.getChildren(LISTENER_TAG);

                 for (Iterator iterator = listeners.iterator(); iterator.hasNext();) {

                     pluginConfig.addListener(parseListenerProperties((Element)iterator.next()));

                 }

         }

         private String parseListenerProperties(Element element) throws XmlException {

                 String listenerClass = element.getChildText(LISTENER_CLASS_TAG);

                 if (org.apache.commons.lang.StringUtils.isEmpty(listenerClass)) {

                         throw new XmlException("Listener Class tag must have a class property defined");

                 }

                 return listenerClass;

         }

         public Map parseParameters(Element element) throws XmlException {

         Map parsedParms = new HashMap();

             List parameters = element.getChildren(PARAMETER_TAG);

                 for (Iterator iterator = parameters.iterator(); iterator.hasNext();) {

                     String [] parm = parseParameter((Element)iterator.next());

                     parsedParms.put(parm[0], parm[1]);

                 }

                 return parsedParms;

         }

         private String [] parseParameter(Element element) throws XmlException {

                 String name = element.getAttributeValue(NAME_ATTRIBUTE);

                 String value = element.getAttributeValue(VALUE_ATTRIBUTE);

                 if (org.apache.commons.lang.StringUtils.isEmpty(name)) {

                         throw new XmlException("Parameter tag must have a name attribute defined");

                 }

                 if (org.apache.commons.lang.StringUtils.isEmpty(value)) {

                         throw new XmlException("Parameter tag must have a value attribute defined");

                 }

                 return new String [] {name, value};

         }

 }