/*

  * Copyright 2007 The Kuali Foundation

  *

  * Licensed under the Educational Community License, Version 1.0 (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/ecl1.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.kns.datadictionary.view;

 import java.util.ArrayList;

 import java.util.HashMap;

 import java.util.List;

 import java.util.Map;

 import java.util.Map.Entry;

 import org.apache.commons.lang.StringUtils;

 import org.apache.commons.logging.Log;

 import org.apache.commons.logging.LogFactory;

 import org.kuali.rice.kns.datadictionary.DataDictionaryException;

 import org.kuali.rice.kns.service.KNSServiceLocatorWeb;

 import org.kuali.rice.kns.uif.container.View;

 import org.kuali.rice.kns.uif.service.ViewTypeService;

 import org.springframework.beans.factory.support.DefaultListableBeanFactory;

 /**

  * Indexes <code>View</code> bean entries for retrieval

  * 

  * <p>

  * Builds up a Map index where the key is the view id, and the value is the bean

  * name. This is used to retrieve a <code>View</code> instance by its unique id.

  * Furthermore, view of certain types (that have a <code>ViewTypeService</code>

  * are indexed by their type to support retrieval of views based on parameters.

  * </p>

  * 

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

  */

 public class ViewDictionaryIndex implements Runnable {

         private static final Log LOG = LogFactory.getLog(ViewDictionaryIndex.class);

         private DefaultListableBeanFactory ddBeans;

         // view entries keyed by view id with value the spring bean name

         private Map<String, String> viewBeanEntriesById;

         // view entries keyed by bean name with value the view prototype

         private Map<String, View> viewEntriesByBean;

         // view entries indexed by type

         private Map<String, ViewTypeDictionaryIndex> viewEntriesByType;

         public ViewDictionaryIndex(DefaultListableBeanFactory ddBeans) {

                 this.ddBeans = ddBeans;

         }

         public void run() {

                 LOG.info("Starting View Index Building");

                 buildViewIndicies();

                 LOG.info("Completed View Index Building");

         }

         /**

          * Retrieves the View instance with the given id from the bean factory.

          * Since View instances are stateful, we need to get a new instance from

          * Spring each time.

          * 

          * @param viewId

          *            - the unique id for the view

          * @return <code>View</code> instance

          */

         public View getViewById(String viewId) {

                 String beanName = viewBeanEntriesById.get(viewId);

                 if (StringUtils.isBlank(beanName)) {

                         throw new DataDictionaryException("Unable to find View with id: " + viewId);

                 }

                 return ddBeans.getBean(beanName, View.class);

         }

         /**

          * Retrieves a <code>View</code> instance that is of the given type based on

          * the index key

          * 

          * @param viewTypeName

          *            - type name for the view

          * @param indexKey

          *            - Map of index key parameters, these are the parameters the

          *            indexer used to index the view initially and needs to identify

          *            an unique view instance

          * @return View instance that matches the given index or Null if one is not

          *         found

          */

         public View getViewByTypeIndex(String viewTypeName, Map<String, String> indexKey) {

                 String index = buildTypeIndex(indexKey);

                 ViewTypeDictionaryIndex typeIndex = getTypeIndex(viewTypeName);

                 String beanName = typeIndex.get(index);

                 if (StringUtils.isBlank(beanName)) {

                         throw new DataDictionaryException("Unable to find View with index: " + index);

                 }

                 return ddBeans.getBean(beanName, View.class);

         }

         /**

          * Gets all <code>View</code> prototypes configured for the given view type

          * name

          * 

          * @param viewTypeName

          *            - view type name to retrieve

          * @return List<View> view prototypes with the given type name, or empty

          *         list

          */

         public List<View> getViewsForType(String viewTypeName) {

                 List<View> typeViews = new ArrayList<View>();

                 // get view ids for the type

                 if (viewEntriesByType.containsKey(viewTypeName)) {

                         ViewTypeDictionaryIndex typeIndex = viewEntriesByType.get(viewTypeName);

                         for (Entry<String, String> typeEntry : typeIndex.getViewIndex().entrySet()) {

                                 // get the view prototype by bean name

                                 if (viewEntriesByBean.containsKey(typeEntry.getValue())) {

                                         View typeView = viewEntriesByBean.get(typeEntry.getValue());

                                         typeViews.add(typeView);

                                 }

                         }

                 }

                 else {

                         throw new DataDictionaryException("Unable to find view index for type: " + viewTypeName);

                 }

                 return typeViews;

         }

         /**

          * Initializes the view index <code>Map</code> then iterates through all the

          * beans in the factory that implement <code>View</code>, adding them to the

          * index

          */

         protected void buildViewIndicies() {

                 viewBeanEntriesById = new HashMap<String, String>();

                 viewEntriesByBean = new HashMap<String, View>();

                 viewEntriesByType = new HashMap<String, ViewTypeDictionaryIndex>();

                 Map<String, View> viewBeans = ddBeans.getBeansOfType(View.class);

                 for (String beanName : viewBeans.keySet()) {

                         View view = viewBeans.get(beanName);

                         if (viewBeanEntriesById.containsKey(view.getId())) {

                                 throw new DataDictionaryException("Two views must not share the same id. Found duplicate id: "

                                                 + view.getId());

                         }

                         viewBeanEntriesById.put(view.getId(), beanName);

                         viewEntriesByBean.put(beanName, view);

                         indexViewForType(view, beanName);

                 }

         }

         /**

          * Performs additional indexing based on the view type associated with the

          * view instance. The <code>ViewTypeService</code> associated with the view

          * type name on the instance is invoked to retrieve the parameter key/value

          * pairs from the view instance, which are then used to build up an index

          * which will key the entry

          * 

          * @param view

          *            - view instance to index

          * @param beanName

          *            - name of the view's bean in Spring

          */

         protected void indexViewForType(View view, String beanName) {

                 String viewType = view.getViewTypeName();

                 ViewTypeService typeService = KNSServiceLocatorWeb.getViewService().getViewTypeService(viewType);

                 if (typeService == null) {

                         // don't do any further indexing

                         return;

                 }

                 // invoke type service to retrieve it parameter name/value pairs from

                 // the view

                 Map<String, String> typeParameters = typeService.getParametersFromView(view);

                 // build the index string from the parameters

                 String index = buildTypeIndex(typeParameters);

                 // get the index for the type and add the view entry

                 ViewTypeDictionaryIndex typeIndex = getTypeIndex(viewType);

                 typeIndex.put(index, beanName);

         }

         /**

          * Retrieves the <code>ViewTypeDictionaryIndex</code> instance for the given

          * view type name. If one does not exist yet for the given name, a new

          * instance is created

          * 

          * @param viewType

          *            - name of the view type to retrieve index for

          * @return ViewTypeDictionaryIndex instance

          */

         protected ViewTypeDictionaryIndex getTypeIndex(String viewType) {

                 ViewTypeDictionaryIndex typeIndex = null;

                 if (viewEntriesByType.containsKey(viewType)) {

                         typeIndex = viewEntriesByType.get(viewType);

                 }

                 else {

                         typeIndex = new ViewTypeDictionaryIndex();

                         viewEntriesByType.put(viewType, typeIndex);

                 }

                 return typeIndex;

         }

         /**

          * Builds up an index string from the given Map of parameters

          * 

          * @param typeParameters

          *            - Map of parameters to use for index

          * @return String index

          */

         protected String buildTypeIndex(Map<String, String> typeParameters) {

                 String index = "";

                 for (String parameterName : typeParameters.keySet()) {

                         if (StringUtils.isNotBlank(index)) {

                                 index += "|||";

                         }

                         index += parameterName + "^^" + typeParameters.get(parameterName);

                 }

                 return index;

         }

 }