/**
    *    Copyright 2009-2015 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.builder;
  
  import java.util.Arrays;
  import java.util.HashSet;
  import java.util.Set;
  import java.util.regex.Pattern;
  
  import org.apache.ibatis.mapping.ParameterMode;
  import org.apache.ibatis.mapping.ResultSetType;
  import org.apache.ibatis.session.Configuration;
  import org.apache.ibatis.type.JdbcType;
  import org.apache.ibatis.type.TypeAliasRegistry;
  import org.apache.ibatis.type.TypeHandler;
  import org.apache.ibatis.type.TypeHandlerRegistry;
  
  /**
   * @author Clinton Begin
   */
  public abstract class BaseBuilder {
    protected final Configuration configuration;
    protected final TypeAliasRegistry typeAliasRegistry;
    protected final TypeHandlerRegistry typeHandlerRegistry;
  
    public BaseBuilder(Configuration configuration) {
      this.configuration = configuration;
      this.typeAliasRegistry = this.configuration.getTypeAliasRegistry();
      this.typeHandlerRegistry = this.configuration.getTypeHandlerRegistry();
    }
  
    public Configuration getConfiguration() {
      return configuration;
    }
  
    protected Pattern parseExpression(String regex, String defaultValue) {
      return Pattern.compile(regex == null ? defaultValue : regex);
    }
  
    protected Boolean booleanValueOf(String value, Boolean defaultValue) {
      return value == null ? defaultValue : Boolean.valueOf(value);
    }
  
    protected Integer integerValueOf(String value, Integer defaultValue) {
      return value == null ? defaultValue : Integer.valueOf(value);
    }
  
    protected Set<String> stringSetValueOf(String value, String defaultValue) {
      value = (value == null ? defaultValue : value);
      return new HashSet<String>(Arrays.asList(value.split(",")));
    }
  
    protected JdbcType resolveJdbcType(String alias) {
      if (alias == null) {
        return null;
      }
      try {
        return JdbcType.valueOf(alias);
      } catch (IllegalArgumentException e) {
        throw new BuilderException("Error resolving JdbcType. Cause: " + e, e);
      }
    }
  
    protected ResultSetType resolveResultSetType(String alias) {
      if (alias == null) {
        return null;
      }
      try {
        return ResultSetType.valueOf(alias);
      } catch (IllegalArgumentException e) {
        throw new BuilderException("Error resolving ResultSetType. Cause: " + e, e);
      }
    }
  
    protected ParameterMode resolveParameterMode(String alias) {
      if (alias == null) {
        return null;
      }
      try {
        return ParameterMode.valueOf(alias);
      } catch (IllegalArgumentException e) {
        throw new BuilderException("Error resolving ParameterMode. Cause: " + e, e);
      }
    }
  
    protected Object createInstance(String alias) {
     Class<?> clazz = resolveClass(alias);
     if (clazz == null) {
       return null;
     }
     try {
       return resolveClass(alias).newInstance();
     } catch (Exception e) {
       throw new BuilderException("Error creating instance. Cause: " + e, e);
     }
   }
 
   protected Class<?> resolveClass(String alias) {
     if (alias == null) {
       return null;
     }
     try {
       return resolveAlias(alias);
     } catch (Exception e) {
       throw new BuilderException("Error resolving class. Cause: " + e, e);
     }
   }
 
   protected TypeHandler<?> resolveTypeHandler(Class<?> javaType, String typeHandlerAlias) {
     if (typeHandlerAlias == null) {
       return null;
     }
     Class<?> type = resolveClass(typeHandlerAlias);
     if (type != null && !TypeHandler.class.isAssignableFrom(type)) {
       throw new BuilderException("Type " + type.getName() + " is not a valid TypeHandler because it does not implement TypeHandler interface");
     }
     @SuppressWarnings( "unchecked" ) // already verified it is a TypeHandler
     Class<? extends TypeHandler<?>> typeHandlerType = (Class<? extends TypeHandler<?>>) type;
     return resolveTypeHandler(javaType, typeHandlerType);
   }
 
   protected TypeHandler<?> resolveTypeHandler(Class<?> javaType, Class<? extends TypeHandler<?>> typeHandlerType) {
     if (typeHandlerType == null) {
       return null;
     }
     // javaType ignored for injected handlers see issue #746 for full detail
     TypeHandler<?> handler = typeHandlerRegistry.getMappingTypeHandler(typeHandlerType);
     if (handler == null) {
       // not in registry, create a new one
       handler = typeHandlerRegistry.getInstance(javaType, typeHandlerType);
     }
     return handler;
   }
 
   protected Class<?> resolveAlias(String alias) {
     return typeAliasRegistry.resolveAlias(alias);
   }
 }