package net.sf.sapjcosupport;

 import org.apache.log4j.Logger;

 import org.springframework.core.io.ClassPathResource;

 import org.springframework.util.xml.DomUtils;

 import org.w3c.dom.Document;

 import org.w3c.dom.Element;

 import javax.xml.parsers.DocumentBuilder;

 import javax.xml.parsers.DocumentBuilderFactory;

 import java.util.*;

 /**

  * This class parses a VO SAP mapping and caches it internally.

  *

  * @author Jo Vandermeeren

  * @since Jan 18, 2006 - 5:34:08 PM

  */

 public class SapMappingParser {

     private static final Logger logger = Logger.getLogger(SapMappingParser.class);

     /**

      * Internal caching class for <code>SapMapping</code> instances.

      */

     private static class MappingCache {

         private static Map cache;

         static {

             cache = Collections.synchronizedMap(new HashMap());

         }

         public static synchronized SapMapping get(Class persistentClass) {

             return (SapMapping) cache.get(persistentClass);

         }

         public static synchronized void register(Class persistentClass, SapMapping mapping) {

             if (logger.isInfoEnabled()) {

                 logger.info("Caching mapping for entity " + persistentClass.getName());

             }

             cache.put(persistentClass, mapping);

         }

     }

     /**

      * This method retrieves a cached mapping for a given value object class (VO).

      * If it doesn.t exist in cache, it will be looked up, parsed, cached and returned.

      *

      * @param clazz VO class

      * @return SAP mapping for the given class

      * @throws SapJcoMappingException if something goes wrong when creating the SAP mapping

      */

     public synchronized static SapMapping getInfo(Class clazz) throws SapJcoMappingException {

         SapMapping mapping = MappingCache.get(clazz);

         if (mapping == null) {

             if (logger.isInfoEnabled()) {

                 logger.info("Mapping for entity '" + clazz.getName() + "' not cached yet, parsing mapping definition");

             }

             mapping = parseMapping(clazz);

             MappingCache.register(clazz, mapping);

         }

         return mapping;

     }

     /**

      * This helper method tries to find the SAP JCO mapping file in the same classpath location as the

      * <code>clazz</code> class definition. The mapping file has the same name as the class and ends with ".sap.xml".

      * This file is read and parsed to a <code>SapMapping</code> object.

      *

      * @param clazz the VO class

      * @return SAP mapping

      * @throws SapJcoMappingException if something goes wrong when creating the SAP mapping

      */

     private static SapMapping parseMapping(Class clazz) throws SapJcoMappingException {

         try {

             String fqName = clazz.getName();

             String resource = fqName.replace('.', '/');

             String shortName = fqName.substring(fqName.lastIndexOf(".") + 1);

             ClassPathResource classPathResource = new ClassPathResource(resource + ".sap.xml");

             DocumentBuilder builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();

             Document mappingXml = builder.parse(classPathResource.getInputStream());

             Element root = mappingXml.getDocumentElement();

             List classDefs = DomUtils.getChildElementsByTagName(root, "class");

             if (classDefs == null || classDefs.size() == 0) {

                 throw new SapJcoMappingException(

                         "SAP Mapping xml '" + shortName + ".sap.xml' should contain 1 <class/> definition");

             }

             Element classDef = (Element) classDefs.get(0);

             String className = classDef.getAttribute("name");

             String bapiName = classDef.getAttribute("bapi");

             if (className == null || className.trim().length() == 0) {

                 throw new SapJcoMappingException("'name' attribute of 'class' element is required");

             }

             SapMapping sapMapping = new SapMapping(className);

             boolean fieldSelectionExists = false;

             // Check if a lists elements is available and if available process the input and output list

             List lists = DomUtils.getChildElementsByTagName(root, "list");

             for (int i = 0; i < lists.size(); i++) {

                 Element listsElement = (Element) lists.get(i);

                 List inputLists = DomUtils.getChildElementsByTagName(listsElement, "inputList");

                 for (Iterator inputListIterator = inputLists.iterator(); inputListIterator.hasNext();) {

                     Element inputListElement = (Element) inputListIterator.next();

                     String[] listAttributes = extractListElementAttributes(inputListElement);

                     if (listAttributes != null) {

                         sapMapping.addInputList(new SapListMapping(listAttributes[0], listAttributes[1]));

                     }

                 }

                 String[] listAttributes = selectAndExtractListElementAttributes(listsElement, "outputList");

                 if (listAttributes != null) {

                     sapMapping.setOutputList(new SapListMapping(listAttributes[0], listAttributes[1]));

                 }

                 listAttributes = selectAndExtractListElementAttributes(listsElement, "fieldSelection");

                 if (listAttributes != null) {

                     fieldSelectionExists = true;

                     sapMapping.setFieldSelection(new SapListMapping(listAttributes[0], listAttributes[1]));

                 }

             }

             Map fieldSelectionMap = new HashMap();

             if (bapiName == null || bapiName.length() == 0) {

                 throw new SapJcoMappingException("'bapi' attribute of 'class' element is required");

             }

             SapBapiMapping bapi = new SapBapiMapping(bapiName);

             //loop over structures

             List structureList = DomUtils.getChildElementsByTagName(classDef, "structure");

             for (int j = 0; j < structureList.size(); j++) {

                 Element structureElement = (Element) structureList.get(j);

                 String structureName = structureElement.getAttribute("name");

                 if (structureName == null || structureName.length() == 0) {

                     throw new SapJcoMappingException("'name' attribute of 'structure' element is required");

                 }

                 String mappingType = structureElement.getAttribute("type");

                 SapStructureMapping structure;

                 if ("list".equalsIgnoreCase(mappingType)) {

                     String keyField = structureElement.getAttribute("key-field");

                     String primaryKey = structureElement.getAttribute("pk");

                     if (keyField != null && keyField.trim().length() > 0 && primaryKey != null && primaryKey.trim()

                             .length() > 0) {

                         // List of Maps

                         structure = new SapStructureMapping(structureName, SapStructureMapping.LIST_OF_MAPS);

                         structure.setKeyField(keyField);

                         structure.setPrimaryKey(primaryKey);

                     } else {

                         // List

                         structure = new SapStructureMapping(structureName, SapStructureMapping.LIST);

                     }

                 } else if ("map".equalsIgnoreCase(mappingType)) {

                     String keyField = structureElement.getAttribute("key-field");

                     if (keyField == null || keyField.length() == 0) {

                         throw new SapJcoMappingException(

                                 "'key-field' attribute of 'structure' element is required when 'type' is 'map'");

                     }

                     // Map

                     structure = new SapStructureMapping(structureName, SapStructureMapping.MAP);

                     structure.setKeyField(keyField);

                 } else if ("entity".equalsIgnoreCase(mappingType)) {

                     String entityClass = structureElement.getAttribute("class");

                     String collection = structureElement.getAttribute("collection");

                     structure = new SapStructureMapping(structureName, SapStructureMapping.ENTITY);

                     structure.setCollectionName(collection);

                     structure.setEntityClass(entityClass);

                 } else {

                     structure = new SapStructureMapping(structureName);

                 }

                 // This attribute defines if we're going to skip this structure when processing the output from SAP.

                 // Structures that do not contain return values, should usually be skipped when mapping value objects.

                 String excluded = structureElement.getAttribute("excluded");

                 if ("true".equalsIgnoreCase(excluded)) {

                     structure.setExcluded(true);

                 }

                 //loop over properties

                 List propertyList = DomUtils.getChildElementsByTagName(structureElement, "property");

                 for (int k = 0; k < propertyList.size(); k++) {

                     Element propertyElement = (Element) propertyList.get(k);

                     String propertyName = propertyElement.getAttribute("name");

                     String fieldName = propertyElement.getAttribute("field");

                     String key = propertyElement.getAttribute("key");

                     String type = propertyElement.getAttribute("type");

                     String not_null = propertyElement.getAttribute("not-null");

                     if (fieldSelectionExists) {

                         String profiles = propertyElement.getAttribute("profiles");

                         if (profiles != null) {

                             StringTokenizer st = new StringTokenizer(profiles, ",", false);

                             while (st.hasMoreTokens()) {

                                 String profile = st.nextToken();

                                 List selection = (List) fieldSelectionMap.get(profile);

                                 if (selection == null) {

                                     selection = new ArrayList();

                                 }

                                 selection.add(fieldName);

                                 fieldSelectionMap.put(profile, selection);

                             }

                         }

                     }

                     if (not_null == null || not_null.length() == 0) {

                         not_null = "false";

                     }

                     if (!("true".equalsIgnoreCase(not_null) || "false".equalsIgnoreCase(not_null))) {

                         throw new SapJcoMappingException(

                                 "'not-null' attribute of 'property' element should be 'false' or 'true'");

                     }

                     if (propertyName == null || propertyName.length() == 0) {

                         throw new SapJcoMappingException("'name' attribute of 'property' element is required");

                     }

                     if (fieldName == null || fieldName.length() == 0) {

                         throw new SapJcoMappingException("'field' attribute of 'property' element is required");

                     }

                     if (type == null || type.length() == 0) {

                         type = "string";

                     }

                     boolean required = Boolean.valueOf(not_null).booleanValue();

                     if (structure.isMap() || structure.isListOfMaps()) {

                         if (key == null || key.length() == 0) {

                             throw new SapJcoMappingException(

                                     "'key' attribute of 'property' element is required when the structure is of type 'map'");

                         }

                         structure.addField(new SapFieldMapping(propertyName, fieldName, type, key, className,

                                                                required));

                     } else {

                         structure.addField(new SapFieldMapping(propertyName, fieldName, type, className, required));

                     }

                 }

                 bapi.addStructure(structure);

             }

             //read input settings: <input name="PLANT" not-null="false" default="NC01"/>

             List inputList = DomUtils.getChildElementsByTagName(classDef, "input");

             for (int j = 0; j < inputList.size(); j++) {

                 Element inputElement = (Element) inputList.get(j);

                 String inputName = inputElement.getAttribute("name");

                 String inputDefault = inputElement.getAttribute("default");

                 String notNull = inputElement.getAttribute("not-null");

                 String pk = inputElement.getAttribute("pk");

                 if (inputName == null || inputName.length() == 0) {

                     throw new SapJcoMappingException("'name' attribute of 'input' element is required");

                 }

                 boolean required = toBoolean(notNull, "false");

                 boolean isPk = toBoolean(pk, "false");

                 bapi.addInput(new SapInput(inputName, inputDefault, required, isPk));

             }

             bapi.setFieldSelection(fieldSelectionMap);

             sapMapping.setBapi(bapi);

             return sapMapping;

         } catch (Exception e) {

             String msg = new StringBuffer("Error loading mapping info for entity '").append(clazz.getName()).append("'")

                     .toString();

             logger.error(msg, e);

             throw new SapJcoMappingException(msg);

         }

     }

     /**

      * This helper method extracts the first child element with name <code>childElement</code> from

      * the XML element <code>parentListsElement</code> and extracts the String values that are needed to construct

      * the input resp. output list.

      *

      * @param parentListsElement parent XML element

      * @param childElement       child XML element name

      * @return String array containing <code>name</code> attribute (at position 0) and <code>pk</code> attribute (at position 1)

      * @throws SapJcoMappingException if the 'name' or 'pk' attribute is not available in the XML element

      */

     private static String[] selectAndExtractListElementAttributes(Element parentListsElement,

                                                                   String childElement) throws SapJcoMappingException {

         List list = DomUtils.getChildElementsByTagName(parentListsElement, childElement);

         if (list != null && list.size() > 0) {

             return extractListElementAttributes((Element) list.get(0));

         }

         return null;

     }

     private static String[] extractListElementAttributes(Element element) {

         if (element == null) {

             return null;

         }

         String[] attributes = new String[2];

         attributes[0] = element.getAttribute("name");

         if (attributes[0] == null || attributes[0].trim().length() == 0) {

             throw new SapJcoMappingException("'name' attribute of '" + element + "' element in 'list' is required");

         }

         attributes[1] = element.getAttribute("pk");

         if (attributes[1] == null || attributes[1].trim().length() == 0) {

             throw new SapJcoMappingException("'pk' attribute of '" + element + "' element in 'list' is required");

         }

         return attributes;

     }

     /**

      * Converts String "true" to boolean <code>true</code> and String "false" to boolean <code>false</code>.

      *

      * @param booleanValue String value that should be parsed to boolean

      * @param defaultValue default value to use in case booleanValue is null or zero in length

      * @return boolean that corresponds with the String parameter

      */

     private static boolean toBoolean(String booleanValue, String defaultValue) {

         if (booleanValue == null || booleanValue.length() == 0) {

             booleanValue = defaultValue;

         }

         if (!("true".equalsIgnoreCase(booleanValue) || "false".equalsIgnoreCase(booleanValue))) {

             throw new SapJcoMappingException("boolean attributes should be 'false' or 'true'");

         }

         return Boolean.valueOf(booleanValue).booleanValue();

     }

 }