/*
 * Copyright 2002-2010 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;

import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Map;

import org.hibernate.engine.FilterDefinition;
import org.hibernate.type.Type;
import org.hibernate.type.TypeFactory;

import org.springframework.beans.factory.BeanNameAware;
import org.springframework.beans.factory.FactoryBean;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.util.ReflectionUtils;

/**
 * Convenient FactoryBean for defining Hibernate FilterDefinitions.
 * Exposes a corresponding Hibernate FilterDefinition object.
 *
 * <p>Typically defined as an inner bean within a LocalSessionFactoryBean
 * definition, as the list element for the "filterDefinitions" bean property.
 * For example:
 *
 * <pre>
 * &lt;bean id="sessionFactory" class="org.springframework.orm.hibernate3.LocalSessionFactoryBean"&gt;
 *   ...
 *   &lt;property name="filterDefinitions"&gt;
 *     &lt;list&gt;
 *       &lt;bean class="org.springframework.orm.hibernate3.FilterDefinitionFactoryBean"&gt;
 *         &lt;property name="filterName" value="myFilter"/&gt;
 *         &lt;property name="parameterTypes"&gt;
 *           &lt;map&gt;
 *             &lt;entry key="myParam" value="string"/&gt;
 *             &lt;entry key="myOtherParam" value="long"/&gt;
 *           &lt;/map&gt;
 *         &lt;/property&gt;
 *       &lt;/bean&gt;
 *     &lt;/list&gt;
 *   &lt;/property&gt;
 *   ...
 * &lt;/bean&gt;</pre>
 *
 * Alternatively, specify a bean id (or name) attribute for the inner bean,
 * instead of the "filterName" property.
 *
 * @author Juergen Hoeller
 * @since 1.2
 * @see org.hibernate.engine.FilterDefinition
 * @see LocalSessionFactoryBean#setFilterDefinitions
 */
public class FilterDefinitionFactoryBean implements FactoryBean<FilterDefinition>, BeanNameAware, InitializingBean {

	private static Method heuristicTypeMethod;

	private static Object typeResolver;

	static {
		// Hibernate 3.6 TypeResolver class available?
		try {
			Class trClass = FilterDefinitionFactoryBean.class.getClassLoader().loadClass(
					"org.hibernate.type.TypeResolver");
			heuristicTypeMethod = trClass.getMethod("heuristicType", String.class);
			typeResolver = trClass.newInstance();
		}
		catch (Exception ex) {
			try {
				heuristicTypeMethod = TypeFactory.class.getMethod("heuristicType", String.class);
				typeResolver = null;
			}
			catch (Exception ex2) {
				throw new IllegalStateException("Cannot find Hibernate's heuristicType method", ex2);
			}
		}
	}


	private String filterName;

	private Map<String, Type> parameterTypeMap = new HashMap<String, Type>();

	private String defaultFilterCondition;

	private FilterDefinition filterDefinition;


	/**
	 * Set the name of the filter.
	 */
	public void setFilterName(String filterName) {
		this.filterName = filterName;
	}

	/**
	 * Set the parameter types for the filter,
	 * with parameter names as keys and type names as values.
	 * @see org.hibernate.type.TypeFactory#heuristicType(String)
	 */
	public void setParameterTypes(Map<String, String> parameterTypes) {
		if (parameterTypes != null) {
			this.parameterTypeMap = new HashMap<String, Type>(parameterTypes.size());
			for (Map.Entry<String, String> entry : parameterTypes.entrySet()) {
				this.parameterTypeMap.put(entry.getKey(),
						(Type) ReflectionUtils.invokeMethod(heuristicTypeMethod, typeResolver, entry.getValue()));
			}
		}
		else {
			this.parameterTypeMap = new HashMap<String, Type>();
		}
	}

	/**
	 * Specify a default filter condition for the filter, if any.
	 */
	public void setDefaultFilterCondition(String defaultFilterCondition) {
		this.defaultFilterCondition = defaultFilterCondition;
	}

	/**
	 * If no explicit filter name has been specified, the bean name of
	 * the FilterDefinitionFactoryBean will be used.
	 * @see #setFilterName
	 */
	public void setBeanName(String name) {
		if (this.filterName == null) {
			this.filterName = name;
		}
	}

	public void afterPropertiesSet() {
		this.filterDefinition =
				new FilterDefinition(this.filterName, this.defaultFilterCondition, this.parameterTypeMap);
	}


	public FilterDefinition getObject() {
		return this.filterDefinition;
	}

	public Class<FilterDefinition> getObjectType() {
		return FilterDefinition.class;
	}

	public boolean isSingleton() {
		return true;
	}

}
