/*
 * Copyright 2002-2017 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.dao.support;

import java.util.Map;

import org.aopalliance.intercept.MethodInterceptor;
import org.aopalliance.intercept.MethodInvocation;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryAware;
import org.springframework.beans.factory.BeanFactoryUtils;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.beans.factory.ListableBeanFactory;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.util.ReflectionUtils;

AOP Alliance MethodInterceptor that provides persistence exception translation
based on a given PersistenceExceptionTranslator.
Delegates to the given PersistenceExceptionTranslator to translate a RuntimeException thrown into Spring's DataAccessException hierarchy (if appropriate). If the RuntimeException in question is declared on the target method, it is always propagated as-is (with no translation applied). 
Author:
Rod Johnson, Juergen Hoeller
See Also:
PersistenceExceptionTranslator
Since:
2.0/**
 * AOP Alliance MethodInterceptor that provides persistence exception translation
 * based on a given PersistenceExceptionTranslator.
 *
 * <p>Delegates to the given {@link PersistenceExceptionTranslator} to translate
 * a RuntimeException thrown into Spring's DataAccessException hierarchy
 * (if appropriate). If the RuntimeException in question is declared on the
 * target method, it is always propagated as-is (with no translation applied).
 *
 * @author Rod Johnson
 * @author Juergen Hoeller
 * @since 2.0
 * @see PersistenceExceptionTranslator
 */
public class PersistenceExceptionTranslationInterceptor
		implements MethodInterceptor, BeanFactoryAware, InitializingBean {

	@Nullable
	private volatile PersistenceExceptionTranslator persistenceExceptionTranslator;

	private boolean alwaysTranslate = false;

	@Nullable
	private ListableBeanFactory beanFactory;


	
Create a new PersistenceExceptionTranslationInterceptor.
Needs to be configured with a PersistenceExceptionTranslator afterwards.
See Also:
setPersistenceExceptionTranslator/**
	 * Create a new PersistenceExceptionTranslationInterceptor.
	 * Needs to be configured with a PersistenceExceptionTranslator afterwards.
	 * @see #setPersistenceExceptionTranslator
	 */
	public PersistenceExceptionTranslationInterceptor() {
	}

	
Create a new PersistenceExceptionTranslationInterceptor
for the given PersistenceExceptionTranslator.
Params:
pet – the PersistenceExceptionTranslator to use/**
	 * Create a new PersistenceExceptionTranslationInterceptor
	 * for the given PersistenceExceptionTranslator.
	 * @param pet the PersistenceExceptionTranslator to use
	 */
	public PersistenceExceptionTranslationInterceptor(PersistenceExceptionTranslator pet) {
		Assert.notNull(pet, "PersistenceExceptionTranslator must not be null");
		this.persistenceExceptionTranslator = pet;
	}

	
Create a new PersistenceExceptionTranslationInterceptor, autodetecting
PersistenceExceptionTranslators in the given BeanFactory.
Params:
beanFactory – the ListableBeanFactory to obtaining all
PersistenceExceptionTranslators from/**
	 * Create a new PersistenceExceptionTranslationInterceptor, autodetecting
	 * PersistenceExceptionTranslators in the given BeanFactory.
	 * @param beanFactory the ListableBeanFactory to obtaining all
	 * PersistenceExceptionTranslators from
	 */
	public PersistenceExceptionTranslationInterceptor(ListableBeanFactory beanFactory) {
		Assert.notNull(beanFactory, "ListableBeanFactory must not be null");
		this.beanFactory = beanFactory;
	}


	
Specify the PersistenceExceptionTranslator to use.
Default is to autodetect all PersistenceExceptionTranslators
in the containing BeanFactory, using them in a chain.
See Also:
detectPersistenceExceptionTranslators/**
	 * Specify the PersistenceExceptionTranslator to use.
	 * <p>Default is to autodetect all PersistenceExceptionTranslators
	 * in the containing BeanFactory, using them in a chain.
	 * @see #detectPersistenceExceptionTranslators
	 */
	public void setPersistenceExceptionTranslator(PersistenceExceptionTranslator pet) {
		this.persistenceExceptionTranslator = pet;
	}

	
Specify whether to always translate the exception ("true"), or whether throw the
raw exception when declared, i.e. when the originating method signature's exception
declarations allow for the raw exception to be thrown ("false").
Default is "false". Switch this flag to "true" in order to always translate
applicable exceptions, independent from the originating method signature.
Note that the originating method does not have to declare the specific exception. Any base class will do as well, even throws Exception: As long as the originating method does explicitly declare compatible exceptions, the raw exception will be rethrown. If you would like to avoid throwing raw exceptions in any case, switch this flag to "true". /**
	 * Specify whether to always translate the exception ("true"), or whether throw the
	 * raw exception when declared, i.e. when the originating method signature's exception
	 * declarations allow for the raw exception to be thrown ("false").
	 * <p>Default is "false". Switch this flag to "true" in order to always translate
	 * applicable exceptions, independent from the originating method signature.
	 * <p>Note that the originating method does not have to declare the specific exception.
	 * Any base class will do as well, even {@code throws Exception}: As long as the
	 * originating method does explicitly declare compatible exceptions, the raw exception
	 * will be rethrown. If you would like to avoid throwing raw exceptions in any case,
	 * switch this flag to "true".
	 */
	public void setAlwaysTranslate(boolean alwaysTranslate) {
		this.alwaysTranslate = alwaysTranslate;
	}

	@Override
	public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
		if (this.persistenceExceptionTranslator == null) {
			// No explicit exception translator specified - perform autodetection.
			if (!(beanFactory instanceof ListableBeanFactory)) {
				throw new IllegalArgumentException(
						"Cannot use PersistenceExceptionTranslator autodetection without ListableBeanFactory");
			}
			this.beanFactory = (ListableBeanFactory) beanFactory;
		}
	}

	@Override
	public void afterPropertiesSet() {
		if (this.persistenceExceptionTranslator == null && this.beanFactory == null) {
			throw new IllegalArgumentException("Property 'persistenceExceptionTranslator' is required");
		}
	}


	@Override
	public Object invoke(MethodInvocation mi) throws Throwable {
		try {
			return mi.proceed();
		}
		catch (RuntimeException ex) {
			// Let it throw raw if the type of the exception is on the throws clause of the method.
			if (!this.alwaysTranslate && ReflectionUtils.declaresException(mi.getMethod(), ex.getClass())) {
				throw ex;
			}
			else {
				PersistenceExceptionTranslator translator = this.persistenceExceptionTranslator;
				if (translator == null) {
					Assert.state(this.beanFactory != null, "No PersistenceExceptionTranslator set");
					translator = detectPersistenceExceptionTranslators(this.beanFactory);
					this.persistenceExceptionTranslator = translator;
				}
				throw DataAccessUtils.translateIfNecessary(ex, translator);
			}
		}
	}

	
Detect all PersistenceExceptionTranslators in the given BeanFactory.
Params:
beanFactory – the ListableBeanFactory to obtaining all
PersistenceExceptionTranslators from
See Also:
ChainedPersistenceExceptionTranslator
Returns:
a chained PersistenceExceptionTranslator, combining all
PersistenceExceptionTranslators found in the factory/**
	 * Detect all PersistenceExceptionTranslators in the given BeanFactory.
	 * @param beanFactory the ListableBeanFactory to obtaining all
	 * PersistenceExceptionTranslators from
	 * @return a chained PersistenceExceptionTranslator, combining all
	 * PersistenceExceptionTranslators found in the factory
	 * @see ChainedPersistenceExceptionTranslator
	 */
	protected PersistenceExceptionTranslator detectPersistenceExceptionTranslators(ListableBeanFactory beanFactory) {
		// Find all translators, being careful not to activate FactoryBeans.
		Map<String, PersistenceExceptionTranslator> pets = BeanFactoryUtils.beansOfTypeIncludingAncestors(
				beanFactory, PersistenceExceptionTranslator.class, false, false);
		ChainedPersistenceExceptionTranslator cpet = new ChainedPersistenceExceptionTranslator();
		for (PersistenceExceptionTranslator pet : pets.values()) {
			cpet.addDelegate(pet);
		}
		return cpet;
	}

}