package org.codehaus.plexus.component.configurator.converters.composite;
   
   /*
    * The MIT License
    *
    * Copyright (c) 2004, The Codehaus
    *
    * Permission is hereby granted, free of charge, to any person obtaining a copy of
    * this software and associated documentation files (the "Software"), to deal in
   * the Software without restriction, including without limitation the rights to
   * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
   * of the Software, and to permit persons to whom the Software is furnished to do
   * so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in all
   * copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
   * SOFTWARE.
   */
  
  import java.lang.reflect.Modifier;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.HashSet;
  import java.util.List;
  import java.util.Map;
  import java.util.Set;
  import java.util.SortedSet;
  import java.util.TreeSet;
  
  import org.codehaus.plexus.component.configurator.ComponentConfigurationException;
  import org.codehaus.plexus.component.configurator.ConfigurationListener;
  import org.codehaus.plexus.component.configurator.converters.AbstractConfigurationConverter;
  import org.codehaus.plexus.component.configurator.converters.ConfigurationConverter;
  import org.codehaus.plexus.component.configurator.converters.lookup.ConverterLookup;
  import org.codehaus.plexus.component.configurator.expression.ExpressionEvaluator;
  import org.codehaus.plexus.configuration.PlexusConfiguration;
  import org.codehaus.plexus.util.StringUtils;
  
  /**
   * @author <a href="mailto:michal@codehaus.org">Michal Maczka</a>
   */
  public class CollectionConverter extends AbstractConfigurationConverter {
      public boolean canConvert(Class type) {
          return Collection.class.isAssignableFrom(type) && !Map.class.isAssignableFrom(type);
      }
  
      public Object fromConfiguration(
              ConverterLookup converterLookup,
              PlexusConfiguration configuration,
              Class type,
              Class baseType,
              ClassLoader classLoader,
              ExpressionEvaluator expressionEvaluator,
              ConfigurationListener listener)
              throws ComponentConfigurationException {
          Object retValue = fromExpression(configuration, expressionEvaluator, type);
          if (retValue != null) {
              return retValue;
          }
  
          Class implementation = getClassForImplementationHint(null, configuration, classLoader);
  
          if (implementation != null) {
              retValue = instantiateObject(implementation);
          } else {
              // we can have 2 cases here:
              //  - provided collection class which is not abstract
              //     like Vector, ArrayList, HashSet - so we will just instantantiate it
              // - we have an abtract class so we have to use default collection type
              int modifiers = type.getModifiers();
  
              if (Modifier.isAbstract(modifiers)) {
                  retValue = getDefaultCollection(type);
              } else {
                  try {
                      retValue = type.newInstance();
                  } catch (IllegalAccessException e) {
                      String msg = "An attempt to convert configuration entry " + configuration.getName() + "' into "
                              + type + " object failed: " + e.getMessage();
  
                      throw new ComponentConfigurationException(msg, e);
                  } catch (InstantiationException e) {
                      String msg = "An attempt to convert configuration entry " + configuration.getName() + "' into "
                              + type + " object failed: " + e.getMessage();
  
                      throw new ComponentConfigurationException(msg, e);
                  }
              }
          }
          // now we have collection and we have to add some objects to it
  
          for (int i = 0; i < configuration.getChildCount(); i++) {
             PlexusConfiguration c = configuration.getChild(i);
             // Object o = null;
 
             String configEntry = c.getName();
 
             String name = fromXML(configEntry);
 
             Class childType = getClassForImplementationHint(null, c, classLoader);
 
             if (childType == null && name.indexOf('.') > 0) {
                 try {
                     childType = classLoader.loadClass(name);
                 } catch (ClassNotFoundException e) {
                     // not found, continue processing
                 }
             }
 
             if (childType == null) {
                 // Some classloaders don't create Package objects for classes
                 // so we have to resort to slicing up the class name
 
                 String baseTypeName = baseType.getName();
 
                 int lastDot = baseTypeName.lastIndexOf('.');
 
                 String className;
 
                 if (lastDot == -1) {
                     className = name;
                 } else {
                     String basePackage = baseTypeName.substring(0, lastDot);
 
                     className = basePackage + "." + StringUtils.capitalizeFirstLetter(name);
                 }
 
                 try {
                     childType = classLoader.loadClass(className);
                 } catch (ClassNotFoundException e) {
                     if (c.getChildCount() == 0) {
                         // If no children, try a String.
                         // TODO: If we had generics we could try that instead - or could the component descriptor list
                         // an impl?
                         childType = String.class;
                     } else {
                         throw new ComponentConfigurationException("Error loading class '" + className + "'", e);
                     }
                 }
             }
 
             ConfigurationConverter converter = converterLookup.lookupConverterForType(childType);
 
             Object object = converter.fromConfiguration(
                     converterLookup, c, childType, baseType, classLoader, expressionEvaluator, listener);
 
             Collection collection = (Collection) retValue;
             collection.add(object);
         }
 
         return retValue;
     }
 
     protected Collection getDefaultCollection(Class collectionType) {
         Collection retValue = null;
 
         if (List.class.isAssignableFrom(collectionType)) {
             retValue = new ArrayList();
         } else if (SortedSet.class.isAssignableFrom(collectionType)) {
             retValue = new TreeSet();
         } else if (Set.class.isAssignableFrom(collectionType)) {
             retValue = new HashSet();
         }
 
         return retValue;
     }
 }