/*
    * Copyright 2003 - 2013 The eFaps Team
    *
    * Licensed under the Apache 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.apache.org/licenses/LICENSE-2.0
    *
   * 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.
   *
   * Revision:        $Rev$
   * Last Changed:    $Date$
   * Last Changed By: $Author$
   */
  
  
  package org.efaps.update;
  
  import java.sql.SQLException;
  import java.util.HashMap;
  import java.util.Map;
  
  import org.efaps.ci.CIAdminCommon;
  import org.efaps.db.Context;
  import org.efaps.db.InstanceQuery;
  import org.efaps.db.QueryBuilder;
  import org.efaps.update.util.InstallationException;
  import org.efaps.util.EFapsException;
  
  
  /**
   * TODO comment!
   *
   * @author The eFaps Team
   * @version $Id$
   */
  public final class AppDependency
  {
  
      /**
       * The mapping of all names to their Dependency.
       */
      private static final Map<String, AppDependency> NAME2APPDEPENDENCY = new  HashMap<String, AppDependency>();
  
      /**
       * Name of the AppDependency.
       */
      private final String name;
  
      /**
       * met or not.
       */
      private Boolean met;
  
      /**
       * @param _name the name of the AppDependency
       */
      private AppDependency(final String _name)
      {
          this.name = _name;
      }
  
      /**
       * @return true if the dependency is met
       * @throws InstallationException on error
       */
      public boolean isMet()
          throws InstallationException
      {
          if (this.met == null) {
              try {
                  if (Context.getDbType().existsView(Context.getThreadContext().getConnection(), "V_ADMINTYPE")
                                  && CIAdminCommon.Version.getType() != null) {
                      final QueryBuilder queryBldr = new QueryBuilder(CIAdminCommon.Version);
                      queryBldr.addWhereAttrEqValue(CIAdminCommon.Version.Name, this.name);
                      final InstanceQuery query = queryBldr.getQuery();
                      this.met = query.executeWithoutAccessCheck().size() > 0;
                  } else {
                      this.met = true;
                  }
              } catch (final EFapsException e) {
                  throw new InstallationException("Latest version could not be found", e);
              } catch (final SQLException e) {
                  throw new InstallationException("Latest version could not be found", e);
              } finally {
                  if (this.met == null) {
                      this.met = true;
                  }
              }
          }
          return this.met;
      }
      /**
       * Getter method for the instance variable {@link #name}.
      *
      * @return value of instance variable {@link #name}
      */
     public String getName()
     {
         return this.name;
     }
 
     @Override
     public String toString()
     {
         return this.name;
     }
 
     @Override
     public int hashCode()
     {
         return this.name.hashCode();
     }
 
     @Override
     public boolean equals(final Object _object)
     {
         boolean ret;
         if (_object instanceof AppDependency) {
             ret = this.name.equals(((AppDependency) _object).getName());
         } else {
             ret = false;
         }
         return ret;
     }
 
     /**
      * @param _name name of a AppDependency
      * @return the AppDependency for the given name
      */
     public static AppDependency getAppDependency(final String _name)
     {
         final AppDependency ret;
         if (AppDependency.NAME2APPDEPENDENCY.containsKey(_name)) {
             ret = AppDependency.NAME2APPDEPENDENCY.get(_name);
         } else {
             ret = new AppDependency(_name);
             AppDependency.NAME2APPDEPENDENCY.put(_name, ret);
         }
         return ret;
     }
 
     /**
      *
      */
     public static void initialise()
     {
         AppDependency.NAME2APPDEPENDENCY.clear();
     }
 }