I am trying to write an RPC with Thrift, the client seems to be communicating to the server just fine, and the server creates a list to return to the client (proper format). But then the client somehow cannot recognize the packet as I get this error:
org.apache.thrift.TApplicationException: getEntityByIP failed: unknown result
This is what my thrift file looks like:
struct EntityLookupMessage{
1: list<i32> entityIDs;
}
service EntityJoinService {
list<i32> getEntityByIP(1:string IPval,2:i32 date);
}
And the ServerImpl is the following method:
public List<Integer> getEntityByIP(String IPval, int date) throws TException {
try{
System.out.println("Checking..."+IPval);
List<Integer> response=EntityJoinStandalone.getEntityByIP(entityLookup,IPval, date);
System.out.println(response);
return response;
}finally{
// TODO Auto-generated method stub
return null
}
Which is called by a client like so:
List<Integer> entity = client.getEntityByIP(IPval, date);
Any ideas why this is the case?
Cause
Thrift by design doesn't allow for null results. This is the code of the generated recv_Xxx() function:
public List<Integer> recv_getEntityByIP() throws org.apache.thrift.TException
{
getEntityByIP_result result = new getEntityByIP_result();
receiveBase(result, "getEntityByIP");
if (result.isSetSuccess()) {
return result.success;
}
throw new org.apache.thrift.TApplicationException(
org.apache.thrift.TApplicationException.MISSING_RESULT,
"getEntityByIP failed: unknown result");
}
You have to return a valid result, which is ...
a valid list, which may be empty, but must not be null
an exception thrown on the server
Solution
Remove the return null from your finally clause.
Best practice
Put the result into an object, similar to what you already did with the args:
struct EntityByIP_result {
1: list<i32> data;
}
This way you also leave room for further improvements down the road, you can add new fields to the struct at any time.
Related
I am writing a rest client using java.net which should do a PATCH request. But as PATCH is not a supported method in java.net, I used reflection to make it supported by changing the code like
private void updateConnectionToSupportPatchRequest(final HttpURLConnection conn)
throws ReflectiveOperationException {
try {
final Object targetConn;
if (conn instanceof HttpsURLConnectionImpl) {
final Field delegateField = HttpsURLConnectionImpl.class.getDeclaredField("delegate");
delegateField.setAccessible(true);
targetConn = delegateField.get(conn);
} else {
targetConn = conn;
}
final Field methodField = HttpURLConnection.class.getDeclaredField("method");
methodField.setAccessible(true);
methodField.set(targetConn, "PATCH");
} catch (final NoSuchFieldException ex) {
LOGGER.error("NoSuchFieldException: {} ", ex.getMessage());
}
}
but when I deploy my application which uses my rest client in JBoss, I get this error -
java.lang.NoClassDefFoundError: sun/net/www/protocol/https/HttpsURLConnectionImpl
I looked up on this error and came across this post http://planet.jboss.org/post/dealing_with_sun_jdk_related_noclassdeffounderror_under_jboss
I tried the suggested solution in the post still getting the same error. Any ideas on how to get passed this issue?
P.S. I cannot use the Apache HttpClient or RestEasy(Jboss) as there is another 3PP being used in the project which does not support Apache HttpClient
Have you tried using the workaround X-HTTP-Method-Override before trying to fiddle with internal classes of the JDK? If that's the case, you can use the instance's getClass-method to access fields and use isAssignableFrom as alternative to instanceof.
Another approach to get rid off specifying concrete classes is just trying to get the field in HttpsURLConnection and assuming a non-Https-URLConnection if the field can't be found. This might look like the following code:
private void updateConnectionToSupportPatchRequest(final HttpURLConnection conn)
throws ReflectiveOperationException {
try {
final Object targetConn = conn;
try {
final Field delegateField = findField(conn.getClass(), "delegate");
delegateField.setAccessible(true);
targetConn = delegateField.get(conn);
}
catch(NoSuchFieldException nsfe) {
// no HttpsURLConnection
}
final Field methodField = findField(conn.getClass(), "method");
methodField.setAccessible(true);
methodField.set(targetConn, "PATCH");
} catch (final NoSuchFieldException ex) {
LOGGER.error("NoSuchFieldException: {} ", ex.getMessage());
}
}
private Field findField(Class clazz, String name) throws NoSuchFieldException {
while (clazz != null) {
try {
return clazz.getDeclaredField(name);
}
catch(NoSuchFieldException nsfe) {
// ignore
}
clazz = clazz.getSuperclass();
}
throw new NoSuchFieldException(name);
}
But this might fail at another level because - obviously - the class that is used within JBoss is not the one you implemented the workaround, so fields and methods might be named differently.
I'm very new in openfire and first time using java, I got stuck when I trying to develop plugin for crud. Could you give me some sample to make crud plugin ability? Thanks for your help before...
You can start from this answer: Mapping Openfire Custom plugin with aSmack Client
and follow the official tutorial with first 3 points of the answer.
About CRUD:
Let's assume you want to audit all your messages as XML in your database, so you'll implement a PacketInterceptor just to keep an easy scenario.
Your class plugin will looks like:
public class MyCustomPlugin implements Plugin, PacketInterceptor {//foo}
in method initializePlugin you'll have an invokation like:
public void initializePlugin(PluginManager manager, File pluginDirectory)
{
InterceptorManager.getInstance().addInterceptor(this);
}
and in method interceptPacket something like that:
#Override
public void interceptPacket(Packet packet, Session session,
boolean incoming, boolean processed) throws PacketRejectedException {
if (!processed)
{
boolean done = doMyCRUDAction(packet);
}
if (!done)
{ //do something if error occourred}
}
now let's write on database:
private static final String AUDIT_CHAT =
"INSERT INTO MYTABLE(MESSAGEASXML) VALUES (?)";
private boolean doMyCRUDAction(Packet packet)
{
if ((packet instanceof Message))
{
Message message = (Message) packet.createCopy();
boolean isAudited = false;
Connection con = null;
PreparedStatement statement = null;
try {
con = DbConnectionManager.getConnection();
statement = con.prepareStatement(AUDIT_CHAT);
statement.setString(1, message.toString());
statement.executeQuery();
isAudited = true;
}
catch (SQLException e) {
Log.error(e.getMessage(), e);
}
catch (Exception ex)
{
Log.error(ex.getMessage(), ex);
}
finally {
DbConnectionManager.closeConnection(statement, con);
}
return isAudited;
}
}
please keep in mind this is a reduced snippet of a working code, so there can be some sintax to fix
If your CRUD must follow an explicit IQ request, you'll have to extends an IQHandler and create a custom IQ and send to the client in handleIQ(IQ packet) method. You can check in Openfire sourcecode about detailed and complex implementations.
As per my understanding, I want to follow the best practice for releasing the resources at the end to prevent any connection leaks. Here is my code in HelperClass.
public static DynamoDB getDynamoDBConnection()
{
try
{
dynamoDB = new DynamoDB(new AmazonDynamoDBClient(new ProfileCredentialsProvider()));
}
catch(AmazonServiceException ase)
{
//ase.printStackTrace();
slf4jLogger.error(ase.getMessage());
slf4jLogger.error(ase.getStackTrace());
slf4jLogger.error(ase);
}
catch (Exception e)
{
slf4jLogger.error(e);
slf4jLogger.error(e.getStackTrace());
slf4jLogger.error(e.getMessage());
}
finally
{
dynamoDB.shutdown();
}
return dynamoDB;
}
My doubt is, since the finally block will be executed no matter what, will the dynamoDB returns empty connection because it will be closed in finally block and then execute the return statement? TIA.
Your understanding is correct. dynamoBD.shutdown() will always execute before return dynamoDB.
I'm not familiar with the framework you're working with, but I would probably organize the code as follows:
public static DynamoDB getDynamoDBConnection()
throws ApplicationSpecificException {
try {
return new DynamoDB(new AmazonDynamoDBClient(
new ProfileCredentialsProvider()));
} catch(AmazonServiceException ase) {
slf4jLogger.error(ase.getMessage());
slf4jLogger.error(ase.getStackTrace());
slf4jLogger.error(ase);
throw new ApplicationSpecificException("some good message", ase);
}
}
and use it as
DynamoDB con = null;
try {
con = getDynamoDBConnection();
// Do whatever you need to do with con
} catch (ApplicationSpecificException e) {
// deal with it gracefully
} finally {
if (con != null)
con.shutdown();
}
You could also create an AutoCloseable wrapper for your dynamoDB connection (that calls shutdown inside close) and do
try (DynamoDB con = getDynamoDBConnection()) {
// Do whatever you need to do with con
} catch (ApplicationSpecificException e) {
// deal with it gracefully
}
Yes,dynamoDB will return an empty connection as dynamoBD.shutdow() will be executed before return statement, Always.
Although I am not answering your question about the finally block being executed always (there are several answers to that question already), I would like to share some information about how DynamoDB clients are expected to be used.
The DynamoDB client is a thread-safe object and is intended to be shared between multiple threads - you can create a global one for your application and re-use the object where ever you need it. Generally, the client creation is managed by some sort of IoC container (Spring IoC container for example) and then provided by the container to whatever code needs it through dependency injection.
Underneath the hood, the DynamoDB client maintains a pool of HTTP connections for communicating the DynamoDB endpoint and uses connections from within this pool. The various parameters of the pool can be configured by passing an instance of the ClientConfiguration object when constructing the client. For example, one of the parameters is the maximum number of open HTTP connections allowed.
With the above understanding, I would say that since the DynamoDB client manages the lifecycle of HTTP connections, resource leaks shouldn't really be concern of code that uses the DynamoDB client.
How about we "imitate" the error and see what happens ? This is what I mean:
___Case 1___
try{
// dynamoDB = new DynamoDB(new AmazonDynamoDBClient(new ProfileCredentialsProvider()));
throw new AmazonServiceException("Whatever parameters required to instantiate this exception");
} catch(AmazonServiceException ase)
{
//ase.printStackTrace();
slf4jLogger.error(ase.getMessage());
slf4jLogger.error(ase.getStackTrace());
slf4jLogger.error(ase);
}
catch (Exception e)
{
slf4jLogger.error(e);
slf4jLogger.error(e.getStackTrace());
slf4jLogger.error(e.getMessage());
}
finally
{
//dynamoDB.shutdown();
slf4jLogger.info("Database gracefully shutdowned");
}
___Case 2___
try{
// dynamoDB = new DynamoDB(new AmazonDynamoDBClient(new ProfileCredentialsProvider()));
throw new Exception("Whatever parameters required to instantiate this exception");
} catch(AmazonServiceException ase)
{
//ase.printStackTrace();
slf4jLogger.error(ase.getMessage());
slf4jLogger.error(ase.getStackTrace());
slf4jLogger.error(ase);
}
catch (Exception e)
{
slf4jLogger.error(e);
slf4jLogger.error(e.getStackTrace());
slf4jLogger.error(e.getMessage());
}
finally
{
//dynamoDB.shutdown();
slf4jLogger.info("Database gracefully shutdowned");
}
These exercise could be a perfect place to use unit tests and more specifically mock tests. I suggest you to take a close look at JMockit, which will help you write such tests much more easily.
I’m writing in order to get some help.
To be short, I’m trying to use com.unboundid.ldap.sdk (but it is not necessary - the same problem i get if i use oracle's javax.naming.ldap.*) to handle with ldap transactions, and I get the following error:
Exception in thread "Main Thread" java.lang.AssertionError: Result EndTransactionExtendedResult(resultCode=2 (protocol error), diagnosticMessage='protocol error') did not have the expected result code of '0 (success)'.
at com.unboundid.util.LDAPTestUtils.assertResultCodeEquals(LDAPTestUtils.java:1484)
at pkg.Main.main(Main.java:116)
My program is the following ( I’m using simple example from https://www.unboundid.com/products/ldap-sdk/docs/javadoc/com/unboundid/ldap/sdk/extensions/StartTransactionExtendedRequest.html ) :
public class Main {
public static void main( String[] args ) throws LDAPException {
LDAPConnection connection = null;
try {
connection = new LDAPConnection("***", ***, "***", "***");
} catch (LDAPException e1) {
e1.printStackTrace();
}
// Use the start transaction extended operation to begin a transaction.
StartTransactionExtendedResult startTxnResult;
try
{
startTxnResult = (StartTransactionExtendedResult)
connection.processExtendedOperation(
new StartTransactionExtendedRequest());
// This doesn't necessarily mean that the operation was successful, since
// some kinds of extended operations return non-success results under
// normal conditions.
}
catch (LDAPException le)
{
// For an extended operation, this generally means that a problem was
// encountered while trying to send the request or read the result.
startTxnResult = new StartTransactionExtendedResult(
new ExtendedResult(le));
}
LDAPTestUtils.assertResultCodeEquals(startTxnResult, ResultCode.SUCCESS);
ASN1OctetString txnID = startTxnResult.getTransactionID();
// At this point, we have a transaction available for use. If any problem
// arises, we want to ensure that the transaction is aborted, so create a
// try block to process the operations and a finally block to commit or
// abort the transaction.
boolean commit = false;
try
{
// do nothing
}
finally
{
// Commit or abort the transaction.
EndTransactionExtendedResult endTxnResult;
try
{
endTxnResult = (EndTransactionExtendedResult)
connection.processExtendedOperation(
new EndTransactionExtendedRequest(txnID, commit));
}
catch (LDAPException le)
{
endTxnResult = new EndTransactionExtendedResult(new ExtendedResult(le));
}
LDAPTestUtils.assertResultCodeEquals(endTxnResult, ResultCode.SUCCESS);
}
}
}
As you can see, I do nothing with the transaction: just start and rolling back, but it still not working.
Connection is ok, and I receive transaction id = F10285501E20C32AE040A8C0070F7502 BUT IT ALWAYS THE SAME - is it all wrigth???
If “// do nothing” replace with some action exception: unwilling to perform.
I’m starting to think that it is OID problem, but I just can’t figure out what is wrong…
OID is on a WebLogic server and it’s version is :
Version Information
ODSM 11.1.1.6.0
OID 11.1.1.6.0
DB 11.2.0.2.0
All ideas will be appreciated.
i try to passing numeric parameter to a web service that receive the value and return it back.
this is the snippet of the web method :
#WebMethod(operationName = "getNumber")
public Integer getNumber(#WebParam(name = "i")
Integer i) {
//TODO write your implementation code here:
System.out.println("number : "+i);
return i;
}
an this is the snippet of my client code :
Map results = FastMap.newInstance();
results.put("result", "success");
String endPoint = "http://localhost:8084/ProvideWS/MathWS";
URL endpoint=null;
try{
endpoint = new URL(endPoint);
}
catch (MalformedURLException e) {
org.ofbiz.base.util.Debug.log("Location not a valid URL "+e);
// TODO: handle exception
}
Service service = null;
Call call = null;
try{
service = new Service();
call = (Call)service.createCall();
call.setTargetEndpointAddress(endpoint);
String nameSpace = "http://ws/";
String serviceName = "getNumber";
call.setOperationName(new QName(nameSpace, serviceName));
call.addParameter("i",org.apache.axis.Constants.XSD_INTEGER , ParameterMode.IN);
call.setReturnType(org.apache.axis.Constants.XSD_INTEGER);
Object msg[] = new Object[]{new Integer(5)};
for (Object o : msg) {
org.ofbiz.base.util.Debug.log("object to be sent===== "+o.toString());
}
Object ret = call.invoke(msg);
results.put("result", "result : "+ ret.toString());
}
catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
org.ofbiz.base.util.Debug.log("exc when running soap client test : "+e);
results.put("result", "error : "+e);
}
return results;
the problem is the return value in the client always 0 (the server received the number as zero), the method i used to pass the parameter works fine when the paramater is String. I.ve tried to hard-coding the return value in server and the output in client is fine, so i thought it must be how the server retrieved the parameter is the problem.
do you have any idea why this is happen and how to solve this?
any help will be appreciated, thanks
I don't know what is causing your problem. But the first thing I would do would be to try to capture the actual request that is being sent to the server. That should give you some clues as to whether the root problem is on the client or server side.