unknowntypehandler.java

本套系统采用了业界当前最为流行的beanAction组件

/*
 *  Copyright 2004 Clinton Begin
 *
 *  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 com.ibatis.sqlmap.engine.type;

import java.lang.reflect.Method;
import java.sql.CallableStatement;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.lang.NoSuchMethodException;

/**
 * Implementation of TypeHandler for dealing with unknown types
 */
public class UnknownTypeHandler extends BaseTypeHandler implements TypeHandler {

  private TypeHandlerFactory factory;
  
  static private boolean usingJavaPre5 = false;
  
  static {
    try  {
      // try getBaseClass, if it throws no exception
      // were in Java <5
      getBaseClass(Class.class);
      usingJavaPre5 = false;
    } catch ( NoSuchMethodException ex )  {
      usingJavaPre5 = true;
    }
  };

  /**
   * Constructor to create via a factory
   * 
   * @param factory - the factory to associate this with
   */
  public UnknownTypeHandler(TypeHandlerFactory factory) {
    this.factory = factory;
  }

  public void setParameter(PreparedStatement ps, int i, Object parameter, String jdbcType)
      throws SQLException {	
	Class searchClass = parameter.getClass();
	if ( usingJavaPre5 )  {
		try  {
	        searchClass = getBaseClass(searchClass);
		}
		catch ( Exception ex ) {
			searchClass = null;
		}
	}
    if ( searchClass == null )  {
        searchClass = parameter.getClass();
    }	
    TypeHandler handler = factory.getTypeHandler(searchClass, jdbcType);
    handler.setParameter(ps, i, parameter, jdbcType);
  } 

  public Object getResult(ResultSet rs, String columnName)
      throws SQLException {
    Object object = rs.getObject(columnName);
    if (rs.wasNull()) {
      return null;
    } else {
      return object;
    }
  }

  public Object getResult(ResultSet rs, int columnIndex)
      throws SQLException {
    Object object = rs.getObject(columnIndex);
    if (rs.wasNull()) {
      return null;
    } else {
      return object;
    }
  }

  public Object getResult(CallableStatement cs, int columnIndex)
      throws SQLException {
    Object object = cs.getObject(columnIndex);
    if (cs.wasNull()) {
      return null;
    } else {
      return object;
    }
  }

  public Object valueOf(String s) {
    return s;
  }

  public boolean equals(Object object, String string) {
    if (object == null || string == null) {
      return object == string;
    } else {
      TypeHandler handler = factory.getTypeHandler(object.getClass());
      Object castedObject = handler.valueOf(string);
      return object.equals(castedObject);
    }
  }

  /**
   * Get the base class of classParam, for top level classes
   * this returns null. For enums, inner and anonymous 
   * classes it returns the enclosing class. The intent 
   * is to use this for enum support in Java 5+.
   * 
   * @param classParam class to get enclosing class of
   * @return Enclosing class
   * @throws NoSuchMethodException when run in pre Java 5.
   */
  private static Class getBaseClass(Class classParam) 
  	throws NoSuchMethodException  {
      String methodName = "getEnclosingClass";

      Method method = null;
      Class result = null;
      try  {
        method = classParam.getClass().getMethod(methodName, (Class[])null);
	    result = (Class)method.invoke(classParam, (Object[])null);
      }
      catch ( Exception ex )  {
    	  throw new NoSuchMethodException(ex.getMessage());
      }
      return result; 
  } 
}