package org.apache.ddlutils.dynabean;
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.
*/
import java.lang.reflect.InvocationTargetException;
import java.util.HashMap;
import java.util.Map;
import org.apache.commons.beanutils.BeanUtils;
import org.apache.commons.beanutils.DynaBean;
import org.apache.commons.beanutils.DynaClass;
import org.apache.ddlutils.model.Table;
/**
* Provides a cache of dyna class instances for a specific model, as well as
* helper methods for dealing with these classes.
*
* @version $Revision: 231110 $
*/
public class DynaClassCache
{
/** A cache of the SqlDynaClasses per table name. */
private Map _dynaClassCache = new HashMap();
/**
* Creates a new dyna bean instance for the given table.
*
* @param table The table
* @return The new empty dyna bean
*/
public DynaBean createNewInstance(Table table) throws SqlDynaException
{
try
{
return getDynaClass(table).newInstance();
}
catch (InstantiationException ex)
{
throw new SqlDynaException("Could not create a new dyna bean for table "+table.getName(), ex);
}
catch (IllegalAccessException ex)
{
throw new SqlDynaException("Could not create a new dyna bean for table "+table.getName(), ex);
}
}
/**
* Creates a new dyna bean instance for the given table and copies the values from the
* given source object. The source object can be a bean, a map or a dyna bean.
* This method is useful when iterating through an arbitrary dyna bean
* result set after performing a query, then creating a copy as a DynaBean
* which is bound to a specific table.
* This new DynaBean can be kept around, changed and stored back into the database.
*
* @param table The table to create the dyna bean for
* @param source Either a bean, a {@link java.util.Map} or a dyna bean that will be used
* to populate the resultint dyna bean
* @return A new dyna bean bound to the given table and containing all the properties from
* the source object
*/
public DynaBean copy(Table table, Object source) throws SqlDynaException
{
DynaBean answer = createNewInstance(table);
try
{
// copy all the properties from the source
BeanUtils.copyProperties(answer, source);
}
catch (InvocationTargetException ex)
{
throw new SqlDynaException("Could not populate the bean", ex);
}
catch (IllegalAccessException ex)
{
throw new SqlDynaException("Could not populate the bean", ex);
}
return answer;
}
/**
* Returns the {@link SqlDynaClass} for the given table. If the it does not
* exist yet, a new one will be created based on the Table definition.
*
* @param table The table
* @return The <code>SqlDynaClass</code> for the indicated table
*/
public SqlDynaClass getDynaClass(Table table)
{
SqlDynaClass answer = (SqlDynaClass)_dynaClassCache.get(table.getName());
if (answer == null)
{
answer = createDynaClass(table);
_dynaClassCache.put(table.getName(), answer);
}
return answer;
}
/**
* Returns the {@link SqlDynaClass} for the given bean.
*
* @param dynaBean The bean
* @return The dyna bean class
*/
public SqlDynaClass getDynaClass(DynaBean dynaBean) throws SqlDynaException
{
DynaClass dynaClass = dynaBean.getDynaClass();
if (dynaClass instanceof SqlDynaClass)
{
return (SqlDynaClass)dynaClass;
}
else
{
// TODO: we could autogenerate an SqlDynaClass here ?
throw new SqlDynaException("The dyna bean is not an instance of a SqlDynaClass");
}
}
/**
* Creates a new {@link SqlDynaClass} instance for the given table based on the table definition.
*
* @param table The table
* @return The new dyna class
*/
private SqlDynaClass createDynaClass(Table table)
{
return SqlDynaClass.newInstance(table);
}
}