How can I understand whether a bean exists in runtime? - java

For example, I have a class
public class Car{
private Motor motor;
public void setMotor(Motor motor){
this.motor = motor;
}
}
My bean looks like
<bean id="car" class="Car">
<property name="motor" ref="${motorProvider.getAvailableMotor()}"/>
</bean>
This method: motorProvider.getAvailableMotor() returns a bean name(string), of which motor I should use.
But there can be a situation when such bean(with such name) is not created. How can I check it?

There are several patterns how to do this. Here is one I often use:
public class Car{
private Motor motor;
#Autowired
private ApplicationContext applicationContext;
#PostConstruct
public void init() {
try {
motor = applicationContext.getBean( Motor.class );
} catch( NoSuchBeanDefinitionException e ) {
motor = new DefaultMotor();
}
}
}
Note you could also call applicationContext.containsBeanDefinition(name) but that would search your context twice (once in containsBeanDefinition() and then second time when you call getBean()) so catching the exception is usually faster.
Since we catch a specific exception that says "bean doesn't exist", using if/else has almost no advantage anymore.

SPeL; something like:
<property name="motor" value="#(if(${motorProvider} != null) ${motorProvider.getAvailableMotor()})"/>
I think it was discussed also here: Spring - set a property only if the value is not null . As they said before for more information see: http://static.springsource.org/spring/docs/3.0.5.RELEASE/reference/expressions.html

Related

Why is caching not working on wrapped reactive Methods [duplicate]

Spring cache is not working when calling cached method from another method of the same bean.
Here is an example to explain my problem in clear way.
Configuration:
<cache:annotation-driven cache-manager="myCacheManager" />
<bean id="myCacheManager" class="org.springframework.cache.ehcache.EhCacheCacheManager">
<property name="cacheManager" ref="myCache" />
</bean>
<!-- Ehcache library setup -->
<bean id="myCache"
class="org.springframework.cache.ehcache.EhCacheManagerFactoryBean" p:shared="true">
<property name="configLocation" value="classpath:ehcache.xml"></property>
</bean>
<cache name="employeeData" maxElementsInMemory="100"/>
Cached service :
#Named("aService")
public class AService {
#Cacheable("employeeData")
public List<EmployeeData> getEmployeeData(Date date){
..println("Cache is not being used");
...
}
public List<EmployeeEnrichedData> getEmployeeEnrichedData(Date date){
List<EmployeeData> employeeData = getEmployeeData(date);
...
}
}
Result :
aService.getEmployeeData(someDate);
output: Cache is not being used
aService.getEmployeeData(someDate);
output:
aService.getEmployeeEnrichedData(someDate);
output: Cache is not being used
The getEmployeeData method call uses cache employeeData in the second call as expected. But when the getEmployeeData method is called within the AService class (in getEmployeeEnrichedData), Cache is not being used.
Is this how spring cache works or am i missing something ?
I believe this is how it works. From what I remember reading, there is a proxy class generated that intercepts all requests and responds with the cached value, but 'internal' calls within the same class will not get the cached value.
From https://code.google.com/p/ehcache-spring-annotations/wiki/UsingCacheable
Only external method calls coming in through the proxy are
intercepted. This means that self-invocation, in effect, a method
within the target object calling another method of the target object,
will not lead to an actual cache interception at runtime even if the
invoked method is marked with #Cacheable.
Since Spring 4.3 the problem could be solved using self-autowiring over #Resource annotation:
#Component
#CacheConfig(cacheNames = "SphereClientFactoryCache")
public class CacheableSphereClientFactoryImpl implements SphereClientFactory {
/**
* 1. Self-autowired reference to proxified bean of this class.
*/
#Resource
private SphereClientFactory self;
#Override
#Cacheable(sync = true)
public SphereClient createSphereClient(#Nonnull TenantConfig tenantConfig) {
// 2. call cached method using self-bean
return self.createSphereClient(tenantConfig.getSphereClientConfig());
}
#Override
#Cacheable(sync = true)
public SphereClient createSphereClient(#Nonnull SphereClientConfig clientConfig) {
return CtpClientConfigurationUtils.createSphereClient(clientConfig);
}
}
The example below is what I use to hit the proxy from within the same bean, it is similar to #mario-eis' solution, but I find it a bit more readable (maybe it's not:-). Anyway, I like to keep the #Cacheable annotations at the service level:
#Service
#Transactional(readOnly=true)
public class SettingServiceImpl implements SettingService {
#Inject
private SettingRepository settingRepository;
#Inject
private ApplicationContext applicationContext;
#Override
#Cacheable("settingsCache")
public String findValue(String name) {
Setting setting = settingRepository.findOne(name);
if(setting == null){
return null;
}
return setting.getValue();
}
#Override
public Boolean findBoolean(String name) {
String value = getSpringProxy().findValue(name);
if (value == null) {
return null;
}
return Boolean.valueOf(value);
}
/**
* Use proxy to hit cache
*/
private SettingService getSpringProxy() {
return applicationContext.getBean(SettingService.class);
}
...
See also Starting new transaction in Spring bean
Here is what I do for small projects with only marginal usage of method calls within the same class. In-code documentation is strongly advidsed, as it may look strage to colleagues. But its easy to test, simple, quick to achieve and spares me the full blown AspectJ instrumentation. However, for more heavy usage I'd advice the AspectJ solution.
#Service
#Scope(proxyMode = ScopedProxyMode.TARGET_CLASS)
class AService {
private final AService _aService;
#Autowired
public AService(AService aService) {
_aService = aService;
}
#Cacheable("employeeData")
public List<EmployeeData> getEmployeeData(Date date){
..println("Cache is not being used");
...
}
public List<EmployeeEnrichedData> getEmployeeEnrichedData(Date date){
List<EmployeeData> employeeData = _aService.getEmployeeData(date);
...
}
}
If you call a cached method from same bean it will be treated as a private method and annotations will be ignored
Yes, the caching will not happen because of the reasons that were already mentioned in the other posts. However I would solve the problem by putting that method to its own class (service in this case). With that your code will be easier to maintain/test and understand.
#Service // or #Named("aService")
public class AService {
#Autowired //or how you inject your dependencies
private EmployeeService employeeService;
public List<EmployeeData> getEmployeeData(Date date){
employeeService.getEmployeeData(date);
}
public List<EmployeeEnrichedData> getEmployeeEnrichedData(Date date){
List<EmployeeData> employeeData = getEmployeeData(date);
...
}
}
#Service // or #Named("employeeService")
public class EmployeeService {
#Cacheable("employeeData")
public List<EmployeeData> getEmployeeData(Date date){
println("This will be called only once for same date");
...
}
}
In my Case I add variable :
#Autowired
private AService aService;
So I call the getEmployeeData method by using the aService
#Named("aService")
public class AService {
#Cacheable("employeeData")
public List<EmployeeData> getEmployeeData(Date date){
..println("Cache is not being used");
...
}
public List<EmployeeEnrichedData> getEmployeeEnrichedData(Date date){
List<EmployeeData> employeeData = aService.getEmployeeData(date);
...
}
}
It will use the cache in this case.
Better approach should be creating another service like ACachingService and call ACachingService.cachingMethod() instead of self Autowiring ( or any other approach trying to self inject). This way you do not fall into Circular dependency, which may be resulted in warning/error when upgrade to newer Spring ( Spring 2.6.6 in my case ) :
ERROR o.s.boot.SpringApplication - Application run failed
org.springframework.beans.factory.BeanCurrentlyInCreationException:
Error creating bean with name 'webSecurityConfig':
Requested bean is currently in creation: Is there an unresolvable circular reference?
We looked at all the solutions here and decided to use a separate class for the cached methods because Spring 5 doesn't like circular dependencies.
Use static weaving to create proxy around your bean. In this case even 'internal' methods would work correctly
I use internal inner bean (FactoryInternalCache) with real cache for this purpose:
#Component
public class CacheableClientFactoryImpl implements ClientFactory {
private final FactoryInternalCache factoryInternalCache;
#Autowired
public CacheableClientFactoryImpl(#Nonnull FactoryInternalCache factoryInternalCache) {
this.factoryInternalCache = factoryInternalCache;
}
/**
* Returns cached client instance from cache.
*/
#Override
public Client createClient(#Nonnull AggregatedConfig aggregateConfig) {
return factoryInternalCache.createClient(aggregateConfig.getClientConfig());
}
/**
* Returns cached client instance from cache.
*/
#Override
public Client createClient(#Nonnull ClientConfig clientConfig) {
return factoryInternalCache.createClient(clientConfig);
}
/**
* Spring caching feature works over AOP proxies, thus internal calls to cached methods don't work. That's why
* this internal bean is created: it "proxifies" overloaded {#code #createClient(...)} methods
* to real AOP proxified cacheable bean method {#link #createClient}.
*
* #see Spring Cache #Cacheable - not working while calling from another method of the same bean
* #see Spring cache #Cacheable method ignored when called from within the same class
*/
#EnableCaching
#CacheConfig(cacheNames = "ClientFactoryCache")
static class FactoryInternalCache {
#Cacheable(sync = true)
public Client createClient(#Nonnull ClientConfig clientConfig) {
return ClientCreationUtils.createClient(clientConfig);
}
}
}
I would like to share what I think is the easiest approach:
Autowire the controller and use to call the method it instead of using the class context this.
The updated code would look like:
#Controller
public class TestController {
#Autowired TestController self;
#RequestMapping("/test")
public String testView(){
self.expensiveMethod();
return "test";
}
#Cacheable("ones")
public void expensiveMethod(){
System.out.println("Cache is not being used");
}
}
The default advice mode for processing caching annotation is “proxy”. At the startup of an application, all the caching annotations like #Caching, #Cacheable, #CacheEvict etc. are scanned and a target proxy class is generated for all of these classes. The proxy allows for intercepting the calls to these cacheable methods, which adds the caching advice/behavior.
So when we invoke the cacheable methods from the same class, as shown below, calls from the clients don’t get intercepted in a way that allows for caching advice to be added to them. Hence, every single time there is an unexpected cache miss.
Solution: Invoke the Cacheable methods from a different bean to use proxy class with caching advice.

DeltaSpike custom ConfigSource with CDI

I am trying to define a custom DeltaSpike ConfigSource. The custom config source will have the highest priority and check the database for the config parameter.
I have a ConfigParameter entity, that simply has a key and a value.
#Entity
#Cacheable
public class ConfigParameter ... {
private String key;
private String value;
}
I have a #Dependent DAO that finds all config parameters.
What I am trying to do now, is define a custom ConfigSource, that is able to get the config parameter from the database. Therefore, I want to inject my DAO in the ConfigSource. So basically something like
#ApplicationScoped
public class DatabaseConfigSource implements ConfigSource {
#Inject
private ConfigParameterDao configParameterDao;
....
}
However, when registering the ConfigSource via META-INF/services/org.apache.deltaspike.core.spi.config.ConfigSource, the class will be instantiated and CDI will not work.
Is there any way to get CDI working in this case?
Thanks in advance, if you need any further information, please let me know.
The main problem is, that the ConfigSource gets instantiated very early on when the BeanManager is not available yet. Even the JNDI lookup does not work at that point in time. Thus, I need to delay the injection/lookup.
What I did now, is add a static boolean to my config source, that I set manually. We have a InitializerService that makes sure that the system is setup properly. At the end of the initialization process, I call allowInitialization() in order to tell the config source, that the bean is injectable now. Next time the ConfigSource is asked, it will be able to inject the bean using BeanProvider.injectFields.
public class DatabaseConfigSource implements ConfigSource {
private static boolean allowInit;
#Inject
private ConfigParameterProvider configParameterProvider;
#Override
public int getOrdinal() {
return 500;
}
#Override
public String getPropertyValue(String key) {
initIfNecessary();
if (configParameterProvider == null) {
return null;
}
return configParameterProvider.getProperty(key);
}
public static void allowInitialization() {
allowInit = true;
}
private void initIfNecessary() {
if (allowInit) {
BeanProvider.injectFields(this);
}
}
}
I have a request-scoped bean that holds all my config variables for type-safe access.
#RequestScoped
public class Configuration {
#Inject
#ConfigProperty(name = "myProperty")
private String myProperty;
#Inject
#ConfigProperty(name = "myProperty2")
private String myProperty2;
....
}
When injecting the Configuration class in a different bean, each ConfigProperty will be resolved. Since my custom DatabaseConfigSource has the highest ordinal (500), it will be used for property resolution first. If the property is not found, it will delegate the resolution to the next ConfigSource.
For each ConfigProperty the getPropertyValue function from the DatabaseConfigSource is called. Since I do not want to retreive the parameters from the database for each config property, I moved the config property resolution to a request-scoped bean.
#RequestScoped
public class ConfigParameterProvider {
#Inject
private ConfigParameterDao configParameterDao;
private Map<String, String> configParameters = new HashMap<>();
#PostConstruct
public void init() {
List<ConfigParameter> configParams = configParameterDao.findAll();
configParameters = configParams.stream()
.collect(toMap(ConfigParameter::getId, ConfigParameter::getValue));
}
public String getProperty(String key) {
return configParameters.get(key);
}
}
I could sure change the request-scoped ConfigParameterProvider to ApplicationScoped. However, we have a multi-tenant setup and the parameters need to be resolved per request.
As you can see, this is a bit hacky, because we need to explicitly tell the ConfigSource, when it is allowed to be instantiated properly (inject the bean).
I would prefer a standarized solution from DeltaSpike for using CDI in a ConfigSource. If you have any idea on how to properly realise this, please let me know.
Even though this post has been answered already I'd like to suggest another possible solution for this problem.
I managed to load properties from my db service by creating an #Signleton #Startup EJB which extends the org.apache.deltaspike.core.impl.config.BaseConfigSource and injects my DAO as delegate which I then registered into the org.apache.deltaspike.core.api.config.ConfigResolver.
#Startup
#Singleton
public class DatabaseConfigSourceBean extends BaseConfigSource {
private static final Logger logger = LoggerFactory.getLogger(DatabaseConfigSourceBean.class);
private #Inject PropertyService delegateService;
#PostConstruct
public void onStartup() {
ConfigResolver.addConfigSources(Collections.singletonList(this));
logger.info("Registered the DatabaseConfigSourceBean in the ConfigSourceProvider ...");
}
#Override
public Map<String, String> getProperties() {
return delegateService.getProperties();
}
#Override
public String getPropertyValue(String key) {
return delegateService.getPropertyValue(key);
}
#Override
public String getConfigName() {
return DatabaseConfigSourceBean.class.getSimpleName();
}
#Override
public boolean isScannable() {
return true;
}
}
I know that creating an EJB for this purpose basically produces a way too big overhead, but I think it's a bit of a cleaner solution instead of handling this problem by some marker booleans with static accessors ...
DS is using the java se spi mechanism for this which is not CD'Injectable'. One solution would be to use the BeanProvider to get hold of your DatabaseConfigSource and delegate operations to it.

Inject based on the package of the class

I have 2 modules containing classes:
blog.model.ArticleDAO
blog.model.CategoryDAO
users.model.UserDAO
users.model.UserGroupDAO
All these DAOs have a dependency on the same service, but I need to inject a different instance based on the package.
I mean the module blog should have a specific instance of MyService, and the module users should have another instance of MyService.
I don't want to create 2 named services because some day I may want to use the same service for all DAOs. Or I could also want to inject another specific instance for a specific class...
Is there a way to inject a service based on the package of a class?
A way to say:
inject foo (instance of MyService) into classes that are in blog.*
inject bar (instance of MyService) into classes that are in users.*
but keeping all my classes unaware of that! Their configuration should only state "Inject an instance of MyService".
First I want to say, I find this a strange requirement. I am also wondering why your DAOs need a Service. In a normal layered design, this is the opposite (the Service uses the DAO).
However I find the challenge interesting, I tried to use a FactoryBean to create a Java Proxy class which would redirect at runtime to the correct instance of MyService depending of the caller package. Here is the code:
public class CallerPackageAwareProxyFactoryBean implements
FactoryBean<MyService>, ApplicationContextAware {
private Class<?> targetServiceType;
private ApplicationContext applicationContext;
private InvocationHandler invocationHandler = new InvocationHandler() {
public Object invoke(Object proxy, Method method, Object[] args)
throws Throwable {
if (ReflectionUtils.isEqualsMethod(method)) {
// Only consider equal when proxies are identical.
return (proxy == args[0]);
} else if (ReflectionUtils.isHashCodeMethod(method)) {
// Use hashCode of service locator proxy.
return System.identityHashCode(proxy);
} else if (ReflectionUtils.isToStringMethod(method)) {
return "Service dispatcher: " + targetServiceType.getName();
} else {
String callerPackageFirstLevel = getCallerPackageFirstLevel();
Map<String, ?> beans = applicationContext
.getBeansOfType(targetServiceType);
for (Map.Entry<String, ?> beanEntry : beans.entrySet()) {
if (beanEntry.getKey().startsWith(callerPackageFirstLevel)) {
return method.invoke(beanEntry.getValue(), args);
}
}
throw new IllegalArgumentException(
String.format(
"Could not find any valid bean to forward call for method %s.",
method.getName()));
}
}
private String getCallerPackageFirstLevel() {
Throwable t = new Throwable();
StackTraceElement[] elements = t.getStackTrace();
String callerClassName = elements[3].getClassName();
return callerClassName.split("\\.")[0];
}
};
public MyService getObject() throws Exception {
return (MyService) Proxy.newProxyInstance(Thread.currentThread()
.getContextClassLoader(), new Class<?>[] { MyService.class },
invocationHandler);
}
public Class<?> getObjectType() {
return MyService.class;
}
public boolean isSingleton() {
return true;
}
public void setApplicationContext(ApplicationContext applicationContext) {
this.applicationContext = applicationContext;
}
public void setTargetServiceType(Class<?> targetServiceType) {
this.targetServiceType = targetServiceType;
}
}
I didn't had to change anything to the Dao or Service configuration. I just had to add the creation of the FactoryBean in the Spring context:
<bean id="myService" class="stackoverflow.CallerPackageAwareProxyFactoryBean">
<property name="targetServiceType" value="a.b.c.MyService" />
</bean>
Maybe a few comments:
The caller package can only be get by creating an exception and looking at the stacktrace.
The code of the InvocationHandler is inspired from ServiceLocatorFactoryBean.
I am still wondering if there is an easier way but I think there is not.
You could replace part of the InvocationHandler to use a configuration Map (package => MyService bean name)
I would not recommend using such code in a productive environment.

Spring Generic Dao class name

I have configured a custom generic service DAO for my spring / hibernate project - the idea being that I can reuse it easily from my controllers.
It essentially looks like this:
public class DefaultService<T> {
private Class<T> e;
public String className(Class<T> e) {
String clip = e.getName();
clip = clip.substring(clip.lastIndexOf('.') + 1, clip.length());
return clip;
}
public List<T> getAll(Integer status) {
Session session = sessionFactory.getCurrentSession();
Query query = session.createQuery("FROM " + className(e) + " WHERE status = " + status);
return query.list();
}
...
Which gets referenced by:
#Autowired
public DefaultService<Address> addressService;
addressService.get(1);
However the String clip = e.getName() line throws a Null pointer exception. I can get this to work if I move the class into the attributes section (so addressService.get(Address.class, 1) but I find this somewhat untidy, especially when there are multiple different classes being called upon.
Is there some way to get the class to generate a value correctly without repeatedly adding it into all my functions?
Thanks in advance.
I did something similar, you need the generic class to be a constructor argument as well, mine uses hibernate entities, but you could pass in the string of table name.
public class DomainRepository<T> {
#Resource(name = "sessionFactory")
protected SessionFactory sessionFactory;
public DomainRepository(Class genericType) {
this.genericType = genericType;
}
#Transactional(readOnly = true)
public T get(final long id) {
return (T) sessionFactory.getCurrentSession().get(genericType, id);
}
You can then subclass (if you need to) to customize or simply set up you bean in the spring config like below t :
<bean id="tagRepository" class="com.yourcompnay.data.DomainRepository">
<constructor-arg value="com.yourcompnay.domain.Tag"/>
</bean>
So in your code you could then reference tagRepository like so (no other cod eis needed than that posted above, and below) :
#Resource(name = "tagRepository")
private DomainRepository<Tag> tagRepository;
Also, I would call it a repository not a service, a service deals with different types and their interactions (not just one). And for specifically your example using SQL strings :
public final String tableName;
public DomainRepository(String tableName) {
this.tableName = tableName;
}
public List<T> getAll(Integer status) {
Session session = sessionFactory.getCurrentSession();
Query query = session.createQuery("FROM " + tableName + " WHERE status = " + status);
return query.list();
}
and have your beans defined like so
<bean id="addressRepository" class="com.yourcompnay.data.DomainRepository">
<constructor-arg value="address"/>
</bean>
And then you can alsow create subclasses youself where necessary :
public class PersonRepository extends DomainRepository<Person> {
public PersonRepository(){
super("person"); //assumes table name is person
}
As I understand you got NPE because you did not set any value for this field.
So you can resolve this problem by 2 ways:
Set manually class object as in comment NimChimpsky.
Get class type dynamically. E.g, if you use Spring try this one:
protected Class getEntityClass() {
return GenericTypeResolver.resolveTypeArguments(getClass(), DefaultService.class)[0];
}
or some workaround here
It's better to define a specific class for Address service
public class AddressService extends DefaultService<Address>{
public String getClassName(){
return "Address";
}
}
where
public String getClassName();
is an abstract method declared in DefaultService, and used (like your method className()) in your data access logic.
Using this approach, you will be able to add specific data access logic (example, getUsersByAddress)

Logging bean id into log4j logfile without BeanNameAware interface

Given a set of classes wired together by spring. There are several classes that are used with different configuration in multiple instances in the environment. They have different beanid of course.
The problems:
When they make log entries, we dont know exactly which bean made the log, since the log4j displays the classname only
I know that I could use logger instantiated by spring InitializationBean+BeanNameAware interface methods, but I do not want to do it, since I do not want to implement them in all classes
The solution could be:
Having some effect on bean factory to store the id of the beans in a map with the bean reference (key is the ref, name is the value)
Creating an aspect to be applied on every method, that would set an "BeanName" MDC entry in Log4j before the call, and would restore it to the previous value after the call. Meanwhile the previous beannames could be stored in a threadlocal in a stack.
The questions:
How can I change/configure the bean factory to do this trick for me? Is there any customization point I could use to this aim?
How can I avoid memory leaks in the map in the beanid registry? Maybe the registry is not needed at all, if somehow spring can look up the id for a reference.
Do you have any better idea, that would not result in changing ten thousand classes?
Thanks in advance.
UPDATE:
- Does anyone have solution for the prototype beans?
I have managed to hack something together based on this Spring AOP Example.
I am not yet up to speed with Spring 3 so I have implemented this using Spring 2.5 - I dare say there are more elegant ways of achieving what you want. I have implemented this using System.out's for simplicity but these could easily be converted to log4j calls.
Initially I create a map between the Spring's bean names and the string representation of the object (InitBean). This map is used inside the MethodInterceptor - I did try making the MethodInterceptor an InitializingBean but the MethodInterceptor stopped working for some reason.
Performing an equals between the bean passed in via the MethodInterceptor and the other beans in the application context did not work. e.g. by using something like "ctx.getBeansOfType(GoBean.class)" inside the MethodInterceptor. I presume this is because the object passed in via the MethodInvocation was a GoBean whereas objects obtained from the application context at this point are proxied (e.g. something like example.GoBean$$EnhancerByCGLIB$$bd27d40e).
This is why I had to resort to a comparison of object string representations (which is not ideal). Also I specifically do not want to activate the MethodInterceptor logic when calling the "toString" method on an object (as since I'm using toString elsewhere leads to infinite loops and StackOverflow).
I hope this is useful,
applicationContext.xml
<beans>
<bean name="initBean" class="example.InitBean"/>
<bean name="methodLoggingInterceptor" class="example.MethodLoggingInterceptor">
<property name="initBean" ref="initBean"/>
</bean>
<bean name="proxyCreator" class="org.springframework.aop.framework.autoproxy.BeanNameAutoProxyCreator">
<property name="beanNames">
<list>
<value>go*</value>
</list>
</property>
<property name="interceptorNames">
<list>
<value>methodLoggingInterceptor</value>
</list>
</property>
</bean>
<bean name="goBean1" class="example.GoBean" />
<bean name="goBean2" class="example.GoBean" />
<bean name="goBean3" class="example.GoBean" />
</beans>
GoBean.java
public class GoBean {
public void execute(){
System.out.println(new Date());
}
}
SimpleTestClass.java
public static void main( String[] args ){
ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml");
ArrayList<GoBean> goBeans = new ArrayList<GoBean>();
goBeans.add((GoBean) ctx.getBean("goBean1"));
goBeans.add((GoBean) ctx.getBean("goBean2"));
goBeans.add((GoBean) ctx.getBean("goBean3"));
for(GoBean g: goBeans){
g.execute();
}
}
InitBean.java
public class InitBean implements ApplicationContextAware, InitializingBean {
private ApplicationContext ctx;
private Map<String, String> beanMap = new HashMap<String,String>();
public void setApplicationContext(ApplicationContext ac) throws BeansException {
ctx = ac;
}
public void afterPropertiesSet() throws Exception {
for(String beanName: ctx.getBeanNamesForType(GoBean.class)){
beanMap.put(ctx.getBean(beanName).toString(), beanName);
}
}
public Map<String,String> getBeanMap(){
return beanMap;
}
}
MethodLoggingInterceptor.java
public class MethodLoggingInterceptor implements MethodInterceptor{
private InitBean initBean;
public Object invoke(MethodInvocation method) throws Throwable {
if (!"toString".equals(method.getMethod().getName())) {
StringBuilder sb = new StringBuilder();
Object obj = method.getThis();
if (obj instanceof GoBean) {
Map<String,String> beanMap = initBean.getBeanMap();
String objToString = obj.toString();
if (beanMap.containsKey(objToString)) {
System.out.println(beanMap.get(objToString));
sb.append("bean: ");
sb.append(beanMap.get(objToString));
sb.append(" : ");
}
}
sb.append(method.getMethod().getDeclaringClass());
sb.append('.');
sb.append(method.getMethod().getName());
System.out.println(sb.toString() + " starts");
Object result = method.proceed();
System.out.println(sb.toString() + " finished");
return result;
} else {
return method.proceed();
}
}
public void setInitBean(InitBean ib) {
this.initBean = ib;
}
}

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