/**
    *    Copyright 2009-2019 the original author or authors.
    *
    *    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.
   */
  package org.apache.ibatis.binding;
  
  import java.util.Collection;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.Set;
  
  import org.apache.ibatis.builder.annotation.MapperAnnotationBuilder;
  import org.apache.ibatis.io.ResolverUtil;
  import org.apache.ibatis.session.Configuration;
  import org.apache.ibatis.session.SqlSession;
  
  /**
   * @author Clinton Begin
   * @author Eduardo Macarron
   * @author Lasse Voss
   */
  public class MapperRegistry {
  
    private final Configuration config;
    private final Map<Class<?>, MapperProxyFactory<?>> knownMappers = new HashMap<>();
  
    public MapperRegistry(Configuration config) {
      this.config = config;
    }
  
    @SuppressWarnings("unchecked")
    public <T> T getMapper(Class<T> type, SqlSession sqlSession) {
      final MapperProxyFactory<T> mapperProxyFactory = (MapperProxyFactory<T>) knownMappers.get(type);
      if (mapperProxyFactory == null) {
        throw new BindingException("Type " + type + " is not known to the MapperRegistry.");
      }
      try {
        return mapperProxyFactory.newInstance(sqlSession);
      } catch (Exception e) {
        throw new BindingException("Error getting mapper instance. Cause: " + e, e);
      }
    }
  
    public <T> boolean hasMapper(Class<T> type) {
      return knownMappers.containsKey(type);
    }
  
    public <T> void addMapper(Class<T> type) {
      if (type.isInterface()) {
        if (hasMapper(type)) {
          throw new BindingException("Type " + type + " is already known to the MapperRegistry.");
        }
        boolean loadCompleted = false;
        try {
          knownMappers.put(type, new MapperProxyFactory<>(type));
          // It's important that the type is added before the parser is run
          // otherwise the binding may automatically be attempted by the
          // mapper parser. If the type is already known, it won't try.
          MapperAnnotationBuildernotationBuilder.html#MapperAnnotationBuilder">MapperAnnotationBuilder parser = new MapperAnnotationBuilder(config, type);
          parser.parse();
          loadCompleted = true;
        } finally {
          if (!loadCompleted) {
            knownMappers.remove(type);
          }
        }
      }
    }
  
    /**
     * @since 3.2.2
     */
    public Collection<Class<?>> getMappers() {
      return Collections.unmodifiableCollection(knownMappers.keySet());
    }
  
    /**
     * @since 3.2.2
     */
    public void addMappers(String packageName, Class<?> superType) {
      ResolverUtil<Class<?>> resolverUtil = new ResolverUtil<>();
      resolverUtil.find(new ResolverUtil.IsA(superType), packageName);
      Set<Class<? extends Class<?>>> mapperSet = resolverUtil.getClasses();
      for (Class<?> mapperClass : mapperSet) {
        addMapper(mapperClass);
      }
    }
 
   /**
    * @since 3.2.2
    */
   public void addMappers(String packageName) {
     addMappers(packageName, Object.class);
   }
 
 }