/**

  * Copyright 2005-2011 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.rule;

 import org.apache.log4j.Logger;

 import org.kuali.rice.core.api.util.xml.XmlJotter;

 import org.w3c.dom.Element;

 import org.w3c.dom.Node;

 import org.w3c.dom.NodeList;

 import javax.xml.xpath.XPath;

 import javax.xml.xpath.XPathConstants;

 import javax.xml.xpath.XPathExpression;

 import javax.xml.xpath.XPathExpressionException;

 import javax.xml.xpath.XPathFactory;

 import java.util.ArrayList;

 import java.util.HashMap;

 import java.util.List;

 import java.util.Map;

 /**

  * Helper class that can parse and generate generic attribute content

  * from Map<String,String> values.

  * 

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

  */

 public class GenericAttributeContent {

     private static final XPathExpression NAME_EXPR;

     private static final XPathExpression VALUE_EXPR;

     private static final XPathExpression FIELD_EXPR;

     static {

         XPath xpath = XPathFactory.newInstance().newXPath();

         try {

             NAME_EXPR = xpath.compile("name");

             VALUE_EXPR = xpath.compile("value");

             FIELD_EXPR = xpath.compile("field");

         } catch (XPathExpressionException xpee) {

             throw new RuntimeException(xpee);

         }

     }

     private final Logger log;

     private final String elementName;

     private final XPathExpression attr_expr;

     public GenericAttributeContent(Class clazz) {

         this(clazz.getName());

     }

     public GenericAttributeContent(String elementName) {

         this.elementName = elementName;

         log = Logger.getLogger(GenericAttributeContent.class + "[" + elementName + "]");

         try {

             attr_expr = XPathFactory.newInstance().newXPath().compile(elementName);

         } catch (XPathExpressionException xpee) {

             throw new RuntimeException(xpee);

         }

     }

     public String generateContent(Map<String, String> properties) {

         if (properties.size() == 0) return "<" + elementName + "/>";

         StringBuilder sb = new StringBuilder();

         sb.append("<" + elementName + ">\r\n");

         for (Map.Entry<String, String> entry: properties.entrySet()) {

             String key = entry.getKey();

             sb.append("  <field>\r\n");

             if (key != null) {

                 sb.append("    <name>" + key + "</name>\r\n");

             } else {

                 log.warn("null key encountered");

             }

             String value = entry.getValue();

             if (value != null) {

                 sb.append("    <value>" + entry.getValue() + "</value>\r\n");

             } else {

                 log.warn("null value encountered for key: " + key);

             }

             sb.append("  </field>\r\n");

         }

         sb.append("</" + elementName + ">\r\n");

         return sb.toString();

     }

     public List<Map<String, String>> parseContent(Element attributeContent) throws XPathExpressionException {

         List<Map<String, String>> attrs = new ArrayList<Map<String, String>>();

         if (attributeContent == null) {

             return attrs;

         }

         log.info("Parsing content: "+ XmlJotter.jotNode(attributeContent));

         NodeList attrNodes = (NodeList) attr_expr.evaluate(attributeContent, XPathConstants.NODESET);

         if (attrNodes != null) {

             for (int i = 0; i < attrNodes.getLength(); i++) {

                 Map<String, String> props = new HashMap<String, String>();

                 attrs.add(props);

                 Node node = attrNodes.item(i);

                 log.info("Found matching attribute: " + XmlJotter.jotNode(node));

                 NodeList fieldNodes = (NodeList) FIELD_EXPR.evaluate(node, XPathConstants.NODESET);

                 for (int j = 0; j < fieldNodes.getLength(); j++) {

                     node = fieldNodes.item(j);

                     log.info("Found matching attribute content field: " + XmlJotter.jotNode(node));

                     Boolean b = (Boolean) NAME_EXPR.evaluate(node, XPathConstants.BOOLEAN);

                     if (!b.booleanValue()) {

                         log.error("Encountered field with no name, skipping!");

                         continue;

                     }

                     String name = NAME_EXPR.evaluate(node);

                     b = (Boolean) VALUE_EXPR.evaluate(node, XPathConstants.BOOLEAN);

                     String value = null;

                     if (b.booleanValue()) {

                         value = VALUE_EXPR.evaluate(node);

                     } else {

                         log.warn("No value defined for transmitted field named: " + name);

                     }

                     log.info("Matching attribute content field value: " + name + "=" + value);

                     props.put(name, value);

                 }

             }

         }

         return attrs;

     }

 }