/*
    * Copyright 2002-2012 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.springframework.orm.hibernate3.support;
  
  import java.io.IOException;
  import java.io.Serializable;
  import java.sql.PreparedStatement;
  import java.sql.ResultSet;
  import java.sql.SQLException;
  import javax.transaction.TransactionManager;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.hibernate.HibernateException;
  import org.hibernate.usertype.UserType;
  import org.hibernate.util.EqualsHelper;
  
  import org.springframework.jdbc.support.lob.LobCreator;
  import org.springframework.jdbc.support.lob.LobCreatorUtils;
  import org.springframework.jdbc.support.lob.LobHandler;
  import org.springframework.orm.hibernate3.LocalSessionFactoryBean;
  
  /**
   * Abstract base class for Hibernate UserType implementations that map to LOBs.
   * Retrieves the LobHandler to use from LocalSessionFactoryBean at config time.
   *
   * <p>For writing LOBs, either an active Spring transaction synchronization
   * or an active JTA transaction (with "jtaTransactionManager" specified on
   * LocalSessionFactoryBean or a Hibernate TransactionManagerLookup configured
   * through the corresponding Hibernate property) is required.
   *
   * <p>Offers template methods for setting parameters and getting result values,
   * passing in the LobHandler or LobCreator to use.
   *
   * @author Juergen Hoeller
   * @since 1.2
   * @see org.springframework.jdbc.support.lob.LobHandler
   * @see org.springframework.jdbc.support.lob.LobCreator
   * @see org.springframework.orm.hibernate3.LocalSessionFactoryBean#setLobHandler
   * @see org.springframework.orm.hibernate3.LocalSessionFactoryBean#setJtaTransactionManager
   */
  public abstract class AbstractLobType implements UserType {
  
  	protected final Log logger = LogFactory.getLog(getClass());
  
  	private final LobHandler lobHandler;
  
  	private final TransactionManager jtaTransactionManager;
  
  
  	/**
  	 * Constructor used by Hibernate: fetches config-time LobHandler and
  	 * config-time JTA TransactionManager from LocalSessionFactoryBean.
  	 * @see org.springframework.orm.hibernate3.LocalSessionFactoryBean#getConfigTimeLobHandler
  	 * @see org.springframework.orm.hibernate3.LocalSessionFactoryBean#getConfigTimeTransactionManager
  	 */
  	protected AbstractLobType() {
  		this(LocalSessionFactoryBean.getConfigTimeLobHandler(),
  			LocalSessionFactoryBean.getConfigTimeTransactionManager());
  	}
  
  	/**
  	 * Constructor used for testing: takes an explicit LobHandler
  	 * and an explicit JTA TransactionManager (can be {@code null}).
  	 */
  	protected AbstractLobType(LobHandler lobHandler, TransactionManager jtaTransactionManager) {
  		this.lobHandler = lobHandler;
  		this.jtaTransactionManager = jtaTransactionManager;
  	}
  
  
  	/**
  	 * This implementation returns false.
  	 */
  	@Override
  	public boolean isMutable() {
  		return false;
  	}
  
  	/**
  	 * This implementation delegates to the Hibernate EqualsHelper.
  	 * @see org.hibernate.util.EqualsHelper#equals
  	 */
  	@Override
  	public boolean equals(Object x, Object y) throws HibernateException {
 		return EqualsHelper.equals(x, y);
 	}
 
 	/**
 	 * This implementation returns the hashCode of the given objectz.
 	 */
 	@Override
 	public int hashCode(Object x) throws HibernateException {
 		return x.hashCode();
 	}
 
 	/**
 	 * This implementation returns the passed-in value as-is.
 	 */
 	@Override
 	public Object deepCopy(Object value) throws HibernateException {
 		return value;
 	}
 
 	/**
 	 * This implementation returns the passed-in value as-is.
 	 */
 	@Override
 	public Serializable disassemble(Object value) throws HibernateException {
 		return (Serializable) value;
 	}
 
 	/**
 	 * This implementation returns the passed-in value as-is.
 	 */
 	@Override
 	public Object assemble(Serializable cached, Object owner) throws HibernateException {
 		return cached;
 	}
 
 	/**
 	 * This implementation returns the passed-in original as-is.
 	 */
 	@Override
 	public Object replace(Object original, Object target, Object owner) throws HibernateException {
 		return original;
 	}
 
 
 	/**
 	 * This implementation delegates to nullSafeGetInternal,
 	 * passing in the LobHandler of this type.
 	 * @see #nullSafeGetInternal
 	 */
 	@Override
 	@Deprecated
 	public final Object nullSafeGet(ResultSet rs, String[] names, Object owner)
 			throws HibernateException, SQLException {
 
 		if (this.lobHandler == null) {
 			throw new IllegalStateException("No LobHandler found for configuration - " +
 				"lobHandler property must be set on LocalSessionFactoryBean");
 		}
 
 		try {
 			return nullSafeGetInternal(rs, names, owner, this.lobHandler);
 		}
 		catch (IOException ex) {
 			throw new HibernateException("I/O errors during LOB access", ex);
 		}
 	}
 
 	/**
 	 * This implementation delegates to nullSafeSetInternal,
 	 * passing in a transaction-synchronized LobCreator for the
 	 * LobHandler of this type.
 	 * @see #nullSafeSetInternal
 	 */
 	@Override
 	@Deprecated
 	public final void nullSafeSet(PreparedStatement st, Object value, int index)
 			throws HibernateException, SQLException {
 
 		if (this.lobHandler == null) {
 			throw new IllegalStateException("No LobHandler found for configuration - " +
 				"lobHandler property must be set on LocalSessionFactoryBean");
 		}
 
 		LobCreator lobCreator = this.lobHandler.getLobCreator();
 		try {
 			nullSafeSetInternal(st, index, value, lobCreator);
 		}
 		catch (IOException ex) {
 			throw new HibernateException("I/O errors during LOB access", ex);
 		}
 		LobCreatorUtils.registerTransactionSynchronization(lobCreator, this.jtaTransactionManager);
 	}
 
 	/**
 	 * Template method to extract a value from the given result set.
 	 * @param rs the ResultSet to extract from
 	 * @param names the column names
 	 * @param owner the containing entity
 	 * @param lobHandler the LobHandler to use
 	 * @return the extracted value
 	 * @throws SQLException if thrown by JDBC methods
 	 * @throws IOException if thrown by streaming methods
 	 * @throws HibernateException in case of any other exceptions
 	 */
 	protected abstract Object nullSafeGetInternal(
 			ResultSet rs, String[] names, Object owner, LobHandler lobHandler)
 			throws SQLException, IOException, HibernateException;
 
 	/**
 	 * Template method to set the given parameter value on the given statement.
 	 * @param ps the PreparedStatement to set on
 	 * @param index the statement parameter index
 	 * @param value the value to set
 	 * @param lobCreator the LobCreator to use
 	 * @throws SQLException if thrown by JDBC methods
 	 * @throws IOException if thrown by streaming methods
 	 * @throws HibernateException in case of any other exceptions
 	 */
 	protected abstract void nullSafeSetInternal(
 		PreparedStatement ps, int index, Object value, LobCreator lobCreator)
 			throws SQLException, IOException, HibernateException;
 
 }