I have some service bean which is accessible by identifier someSpecificService which I need to modify.
Beans are defined in different xml files and are collected together in runtime. So one big xml file is created where all these xmls are imported:
context.xml
....
<import path="spring1.xml" />
<import path="spring2.xml" />
...
So there is following configuration:
<-- definitions from spring1.xml -->
<alias name="defaultSomeSpecificService" alias="someSpecificService" />
<bean id="defaultSomeSpecificService" class="..."/>
....
<!-- definitions from spring2.xml -->
<alias name="myOwnSomeSpecificService" alias="someSpecificService" />
<bean id="myOwnSomeSpecificService" class="..." /> <!-- how to inject previously defined someSpecificService into this new bean? -->
I would like to override someSpecificService from spring1.xml in spring2.xml, however I do need to inject previously defined bean defaultSomeSpecificService and all I know is its alias name someSpecificService which I need to redefine to new bean myOwnSomeSpecificService.
Is it possible to implement?
One solution would be to avoid trying to override the definition, by creating a proxy for the service implementation to intercept all calls towards it.
1) For the sake of the example, suppose the service would be something like:
public interface Service {
public String run();
}
public class ExistingServiceImpl implements Service {
#Override
public String run() {
throw new IllegalStateException("Muahahahaha!");
}
}
2) Implement an interceptor instead of myOwnSomeSpecificService:
import org.aopalliance.intercept.MethodInterceptor;
import org.aopalliance.intercept.MethodInvocation;
public class SomeSpecificServiceInterceptor implements MethodInterceptor {
#Override
public Object invoke(MethodInvocation invocation) throws Throwable {
String status;
try {
// allow the original invocation to actually execute
status = String.valueOf(invocation.proceed());
} catch (IllegalStateException e) {
System.out.println("Existing service threw the following exception [" + e.getMessage() + "]");
status = "FAIL";
}
return status;
}
}
3) In spring2.xml define the proxy creator and the interceptor:
<bean id="serviceInterceptor" class="com.nsn.SomeSpecificServiceInterceptor" />
<bean id="proxyCreator" class="org.springframework.aop.framework.autoproxy.BeanNameAutoProxyCreator">
<property name="beanNames" value="someSpecificService"/>
<property name="interceptorNames">
<list>
<value>serviceInterceptor</value>
</list>
</property>
</bean>
4) Running a small example such as:
public class Main {
public static void main(String[] args) {
Service service = new ClassPathXmlApplicationContext("context.xml").getBean("someSpecificService", Service.class);
System.out.println("Service execution status [" + service.run() + "]");
}
}
... instead of the IllegalStateException stacktrace you'd normally expect, it will print:
Existing service threw the following exception [Muahahahaha!]
Service execution status [FAIL]
Please note that in this example the service instance is not injected in the interceptor as you asked because I had no user for it. However should you really need it, you can easily inject it via constructor/property/etc because the interceptor is a spring bean itself.
Related
We have a spring application deployed on weblogic server. We have a REST webservice in our project. It is a POST call. In the request body of this webservice, a name comes. When our webservice is being called, internally it calls other webservice using RestTemplate.
Now we need to pass more than 10 names in each request, and in turn our webservice should call the other web service 10 times. We need to make it a multi-threaded call.
So we are using ThreadPoolTaskExecutor. The following is the code for the same.
<bean id="threadPoolTaskExecutor" class="org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor">
<property name="corePoolSize" value="3"></property>
<property name="maxPoolSize" value="4"></property>
<property name="WaitForTasksToCompleteOnShutdown" value="true">
</property>
</bean>
public class ApplicationDirectorImpl{
#Autowired
private ThreadPoolTaskExecutor threadPoolTaskExecutor;
....
....
public CustomResponseObject method(){
....
....
List<Future<FutureCustomResponse>> fList = new ArrayList<Future<FutureCustomResponse>>();
for(String name : nameList){
Future<FutureCustomResponse> fut = threadPoolTaskExecutor.submit(new Task(name));
fList.add(fut);
}
for(Future f: fList){
FutureCustomResponse fuResponse = f.get();
}
}
}
public class Task implements Callable<FutureCustomResponse>{
private String name;
public call() throws Exception{
System.out.println("name" + name + " performed by " + Thread.currentThread().getName());
return NameBuild.getPersonalInfo(this.name);
}
}
Now when a request comes with 5 names, it should be serviced by these 3 threads.
We have 2 servers, and so there will be 2 instances of our application. So the threadpool will be created for each server or common between 2 servers.
So in total how many threads will be created? 3 per server or 3 per application?
I have the following sftp bean Id configured in my spring application-context file. It defines two sftp targets which my application is to send different types of files to:
<bean id="targetA"
class="com.sftp.Sender">
<constructor-arg value="${A.host}"/>
<constructor-arg value="${A.username}"/>
<constructor-arg value="${A.remoteDir}"/>
<constructor-arg value="${A.notificationDir}"/>
</bean>
<bean id="targetB" class="com.sftp.Sender">
<constructor-arg value="${B.host}"/>
<constructor-arg value="${B.username}"/>
<constructor-arg value="${B.remoteDir}"/>
</bean>
My main class looks something like this:
public class Main {
Occ occ= ctx.getBean("occ", Occ.class);
public static void main(String[] args) {
if (args != null && args.length >= 1) {
String target = args[0];
occ.rePublish(target);
} else {
String target = "Both";
orc.processReports(target);
}
}
My Occ class something like this:
public class Occ {
public void rePublish(String target) {
processReports(target);
}
public void processReports(String target) {
// determines who the target is and prepare the appropriate
// file to send to that target
if (target.equal("Both")) {
// prepare both target A and B files
}
}
}
Generally, when the program is executed, it should prepare both sets of files for both target A and target B. In certain scenarios, one transfer may fail and I want to be able to prepare and distribute files for just that target. I can only think of passing in the resend target as arguments in main method. But is this the best way to do this? What are your thoughts and how would you do it? Can I restructure the above code in other better ways?
I want to handle multi Thread in spring mvn model. I have written this code
#RequestMapping("/indialCall")
#ResponseBody
public String indialCall(HttpServletRequest request) {
String result = "FAIL";
try {
Map<String, String> paramList = commonUtilities.getParamList(request);
logger.info("indialCall paramList :::" + paramList);
// System.out.println("indial-call paramList :::" + paramList);
result = inDialHandler.processIndialWork(paramList);
logger.info(result);
} catch (Exception e) {
logger.info("Error :" + e);
}
return result;
}
public String processIndialWork(final Map<String, String> paramList) {
final Boolean sendSms = Boolean.parseBoolean(paramList.get(constantService.getSendSms()));
//assume it is always true
if(true){
Thread thread = new Thread(new Runnable() {
#Override
public void run() {
String sessionId = (String) paramList.get(constantService.getInDialSession());
String msisdn = (String) paramList.get(constantService.getInDialMsisdn());
//This method will save the entry into database
saveMissedCall(callStartDate, sessionId, msisdn, vmnNo, advId, enterpriseId, sendSms, advertiser);
}
});
thread.start();
return "1";
}
}
In this code i am using thread creation on every http request. Which is not good for my case.
because system get 50 request /sec. and when i see the cpu usage it is too high.
I am calling this thread for async communication so that calling party can get response instantly
and later on application do the further processing.
I want to use the Executor service but do not know how to do this. Can some one guide me or can write
few line of code for me to implment the correct thread pool executor.
First define a simple taskExecutor in your config file.
<bean id="taskExecutor"
class="org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor">
<property name="corePoolSize" value="5" />
<property name="maxPoolSize" value="10" />
<property name="WaitForTasksToCompleteOnShutdown" value="true" />
</bean>
Create spring bean with prototype scope (prototype is important as you want to give each thread different data), and they
will run simultaneously.
This spring bean will implement runnable with run method and will have class level variable paramlist for getting vales.
public class MyRunnableBean implements runnable{
private Map<String, String> paramList();
// add setter
public void run(){
// your logic
}
}
Inject task executor (singleton) in your existin bean , get the instances of this runnable bean in your existing bean set the paramlist and add it in executor :-
MyRunnableBEan myRunnableBEan = applicationContext.getBean("myRunnable");
myRunnableBean.setParamList(/* your paramlist*/ );
taskExecutor.execute(myRunnableBean);
Correct the compilation and syntax error, this sample code written on notepad, i don't have java on my machine.
I use properties file in spring framework
root-context.xml
<context:property-placeholder location="classpath:config.properties" />
<util:properties id="config" location="classpath:config.properties" />
java code
#Value("#{config[ebookUseYN]}")
String EBOOKUSEYN;
when Using url call(#RequestMapping(value="/recommendbooks" , method=RequestMethod.GET, produces="application/json;charset=UTF-8")).. this work!
but, i use method call,
public void executeInternal(JobExecutionContext arg0) throws JobExecutionException {
IndexManageController indexManage = new IndexManageController();
CommonSearchDTO commonSearchDTO = new CommonSearchDTO();
try {
if("Y".equals(EBOOKUSEYN)){
indexManage.deleteLuceneDocEbook();
indexManage.initialBatchEbook(null, commonSearchDTO);
}
indexManage.deleteLuceneDoc(); <= this point
indexManage.deleteLuceneDocFacet();
indexManage.initialBatch(null, commonSearchDTO);
}catch (Exception e) {
e.printStackTrace();
}
}
when 'this point ' method call, changing controller, and don't read properties file field..
#Value("#{config[IndexBasePath]}")
String IndexBasePath;
#RequestMapping(value="/deleteLuceneDoc" , method=RequestMethod.GET, produces="application/json;charset=UTF-8")
public #ResponseBody ResultCodeMessageDTO deleteLuceneDoc()
throws Exception
{
long startTime = System.currentTimeMillis();
ResultCodeMessageDTO result = new ResultCodeMessageDTO();
System.out.println(IndexBasePath);
}
It doesn't read IndexBasePath
In your code you are creating a new instance of the IndexManageController, Spring doesn't know this instance and as such it will never be processed.
public void executeInternal(JobExecutionContext arg0) throws JobExecutionException {
IndexManageController indexManage = new IndexManageController();
Instead of creating a new instance inject the dependency for the IndexManageController so that it uses the pre-configured instance constructed and managed by Spring. (And remove the line which constructs a new instance of that class).
public class MyJob {
#Autowired
private IndexManageController indexManage;
}
Your configuration is also loading the properties twice
<context:property-placeholder location="classpath:config.properties" />
<util:properties id="config" location="classpath:config.properties" />
Both load the config.properties file. Simply wire the config to the property-placeholder element.
<context:property-placeholder properties-ref="config"/>
<util:properties id="config" location="classpath:config.properties" />
Saves you loading twice and saves you another bean.
Im learning Spring (2 and 3) and i got this method in a ClientDao
public Client getClient(int id) {
List<Client> clients= getSimpleJdbcTemplate().query(
CLIENT_GET,
new RowMapper<Client>() {
public Client mapRow(ResultSet rs, int rowNum) throws SQLException {
Client client = new ClientImpl(); // !! this (1)
client.setAccounts(new HashSet<Account>()); // !! this (2)
client.setId(rs.getInt(1));
client.setName(rs.getString(2));
return client;
}
},id
);
return clients.get(0);
}
and the following Spring wiring:
<bean id="account" class="client.AccountRON" scope="prototype">
<property name="currency" value = "RON" />
<property name="ammount" value="0" />
</bean>
<bean id="client" class="client.ClientImpl" scope="prototype">
<property name="name" value="--client--" />
<property name="accounts">
<set>
</set>
</property>
</bean>
The things is that i dont like the commented lines of java code (1) and (2).
I'm going to start with (2) which i think is the easy one: is there a way i can wire the bean in the .xml file to tell spring to instantiate a set implementation for the 'accounts' set in ClientImpl? so i can get rid of (2)
Now moving on to (1): what happens if the implementation changes ? do i really need to write another DAO for a different implementation? or do i have to construct a BeanFactory ? or is there another more beautiful solution ?
Thanks!
I'm a bit confused here - why have you defined a ClientImpl bean in your XML, but not using it in your Java?
Your already have most of the solution, you just need to fetch a new ClientImpl from Spring each iterations through the loop:
private #Autowired BeanFactory beanFactory;
public Client getClient(int id) {
List<Client> clients= getSimpleJdbcTemplate().query(
CLIENT_GET,
new RowMapper<Client>() {
public Client mapRow(ResultSet rs, int rowNum) throws SQLException {
Client client = beanFactory.getBean(Client.class);
client.setId(rs.getInt(1));
client.setName(rs.getString(2));
return client;
}
},id
);
return clients.get(0);
}
With this approach, the actual construction and initialization of ClientImpl is done by Spring, not your code.