Develop Reference

JUnit test case for Camel route for ActiveMQ

I have a camel route in MyRouteBuilder.java file which is consuming messages from ActiveMQ:
from("activemq:queue:myQueue" )
.process(consumeDroppedMessage)
.log(">>> I am here");
I wrote a test case for the following like this :
#Override
public RouteBuilder createRouteBuilder() throws Exception {
return new MyRouteBuilder();
}
#Test
void testMyTest() throws Exception {
String queueInputMessage = "My Msg";
template.sendBody("activemq:queue:myQueue", queueInputMessage);
assertMockEndpointsSatisfied();
}
When I run the unit test case I get this strange error:
7:53:26.175 [main] DEBUG org.apache.camel.impl.engine.InternalRouteStartupManager - Route: route1 >>> Route[activemq://queue:null -> null]
17:53:26.175 [main] DEBUG org.apache.camel.impl.engine.InternalRouteStartupManager - Starting consumer (order: 1000) on route: route1
17:53:26.175 [main] DEBUG org.apache.camel.support.DefaultConsumer - Build consumer: Consumer[activemq://queue:null]
17:53:26.185 [main] DEBUG org.apache.camel.support.DefaultConsumer - Init consumer: Consumer[activemq://queue:null]
17:53:26.185 [main] DEBUG org.apache.camel.support.DefaultConsumer - Starting consumer: Consumer[activemq://queue:null]
17:53:26.213 [main] DEBUG org.apache.activemq.thread.TaskRunnerFactory - Initialized TaskRunnerFactory[ActiveMQ Task] using ExecutorService: java.util.concurrent.ThreadPoolExecutor#3fffff43[Running, pool size = 0, active threads = 0, queued tasks = 0, completed tasks = 0]
17:53:26.215 [main] DEBUG org.apache.activemq.transport.failover.FailoverTransport - Reconnect was triggered but transport is not started yet. Wait for start to connect the transport.
17:53:26.334 [main] DEBUG org.apache.activemq.transport.failover.FailoverTransport - Started unconnected
17:53:26.334 [main] DEBUG org.apache.activemq.transport.failover.FailoverTransport - Waking up reconnect task
17:53:26.335 [ActiveMQ Task-1] DEBUG org.apache.activemq.transport.failover.FailoverTransport - urlList connectionList:[tcp://localhost:61616], from: [tcp://localhost:61616]
17:53:26.339 [main] DEBUG org.apache.camel.component.jms.DefaultJmsMessageListenerContainer - Established shared JMS Connection
17:53:26.340 [main] DEBUG org.apache.camel.component.jms.DefaultJmsMessageListenerContainer - Resumed paused task: org.springframework.jms.listener.DefaultMessageListenerContainer$AsyncMessageListenerInvoker#58c34bb3
17:53:26.372 [ActiveMQ Task-1] DEBUG org.apache.activemq.transport.failover.FailoverTransport - Attempting 0th connect to: tcp://localhost:61616
17:53:28.393 [ActiveMQ Task-1] DEBUG org.apache.activemq.transport.failover.FailoverTransport - Connect fail to: tcp://localhost:61616, reason: {}
I am especially stumped to see these messages:
Route: route1 >>> Route[activemq://queue:null -> null]
and
urlList connectionList:[tcp://localhost:61616], from: [tcp://localhost:61616]
Why is the queue coming up as null though I have a proper queue name? Also why is the broker url tcp://localhost:61616?
I want to run this unit test case so that it runs properly in all environments like: local, DIT , SIT, PROD etc. So, for that I cannot afford the broker url to be: tcp://localhost:61616.
Any ideas as to what I am doing wrong here and what I should be doing?
EDIT 1:
One of the issues that I am seeing is even before the test class is called, the MyRouteBuilder() inside createRouteBuilder() is invoked, leading to the issues that I see in the log.

The "activemq:queue:.." is telling Camel to use the auto-configure magic behind the scenes (which uses default url) and your use case is beyond that.
You need to configure a connection factory (ActiveMQConnectionFactory) and configure a camel-jms component to use that connection factory.
The connection factory allows you to specify url, userName, password, default connection settings and setup SSL.
A best practice is to externalize the url, userName, password and queue to a properties file so you can change those across the environments-- local, DIT, SIT and prod, etc.
NOTE: Use org.apache.camel/camel-jms component, and not the org.apache.activemq/activemq-camel component. activemq-camel is deprecated and being removed in ActiveMQ 5.17.x.

Instead of setting up an explicit active mq broker , I started using a VM broker .
#Override
protected RoutesBuilder createRouteBuilder() throws Exception {
return new RouteBuilder() {
#Override
public void configure() {
ConnectionFactory connectionFactory = new ActiveMQConnectionFactory("vm://localhost?broker.persistent=false");
ActiveMQComponent activeMQComponent = new ActiveMQComponent();
activeMQComponent.setConnectionFactory(connectionFactory);
context.addComponent("activemq", activeMQComponent);
from("activemq:queue:myQueue").to("mock:collector");
}
};
}
Also , I mistook camel junit as a traditional junit . We don't need to call explicitly the actual route builder class . Instead after setting up my activeMq component up above , I was able to write my test methods, mock my end points for queue and send messages and assert them . Camel is truly versatile . Requires a lot of study though .

Problems in accessing S3 via AWS Java SDK

I'm trying to get and S3 object size via Java AWS SDK (v2), and send it back via HTTP response (this is all inside a HTTP Server using com.sun.net.httpserver.HttpServer). But it doesn't work and shows me the following debug messages.
What's going wrong here? Am I missing anything?
AwsBasicCredentials awsCreds = AwsBasicCredentials.create(
AdapterMain.ACCESS_KEY,
AdapterMain.SECRET_KEY);
s3Client = S3Client.builder().region(region)
.endpointOverride(URI.create(AdapterMain.S3server))
.credentialsProvider(StaticCredentialsProvider.create(awsCreds))
.build();
//TODO
HeadObjectRequest getObjectRequest = HeadObjectRequest.builder()
.bucket(bucketName).key("FILES/"+getMD5(id)+"/FILES/"+id+"/"+id+".txt").build();
HeadObjectResponse objectHead = s3Client.headObject(getObjectRequest);
long size = objectHead.contentLength();
System.out.println("=================================="+size);
response=size+"";
he.sendResponseHeaders(200, response.length());
And here are the logs:
18:44:14.898 [HTTP-Dispatcher] DEBUG software.amazon.awssdk.core.interceptor.ExecutionInterceptorChain - Creating an interceptor chain that will apply interceptors in the following order: [software.amazon.awssdk.core.internal.interceptor.HttpChecksumRequiredInterceptor#62ec69e1, software.amazon.awssdk.awscore.interceptor.HelpfulUnknownHostExceptionInterceptor#1d17dde7, software.amazon.awssdk.services.s3.internal.handlers.EnableChunkedEncodingInterceptor#339b31af, software.amazon.awssdk.services.s3.internal.handlers.DisableDoubleUrlEncodingInterceptor#3d96c2f6, software.amazon.awssdk.services.s3.internal.handlers.EnableTrailingChecksumInterceptor#3cb417c4, software.amazon.awssdk.services.s3.internal.handlers.CreateMultipartUploadRequestInterceptor#1f6f0d50, software.amazon.awssdk.services.s3.internal.handlers.GetObjectInterceptor#7513515b, software.amazon.awssdk.services.s3.internal.handlers.AsyncChecksumValidationInterceptor#7e99ac7d, software.amazon.awssdk.services.s3.internal.handlers.EndpointAddressInterceptor#620f9e5d, software.amazon.awssdk.services.s3.internal.handlers.ExceptionTranslationInterceptor#56d0ac1, software.amazon.awssdk.services.s3.internal.handlers.GetBucketPolicyInterceptor#6a1b0abe, software.amazon.awssdk.services.s3.internal.handlers.PutObjectInterceptor#5952b9c4, software.amazon.awssdk.services.s3.internal.handlers.SyncChecksumValidationInterceptor#473129c5, software.amazon.awssdk.services.s3.internal.handlers.DecodeUrlEncodedResponseInterceptor#2ae718e0, software.amazon.awssdk.services.s3.internal.handlers.CreateBucketInterceptor#181bb9f8]
18:44:14.939 [HTTP-Dispatcher] DEBUG software.amazon.awssdk.core.interceptor.ExecutionInterceptorChain - Interceptor 'software.amazon.awssdk.services.s3.internal.handlers.EndpointAddressInterceptor#620f9e5d' modified the message with its modifyHttpRequest method.
18:44:14.967 [HTTP-Dispatcher] DEBUG software.amazon.awssdk.request - Sending Request: DefaultSdkHttpFullRequest(httpMethod=HEAD, protocol=https, host=file-store.s3-server.dcstore.company.net, port=443, encodedPath=/FILES/f13e/FILES/id_1234/id_1234.txt, headers=[amz-sdk-invocation-id, User-Agent], queryParameters=[])
18:44:14.978 [HTTP-Dispatcher] DEBUG software.amazon.awssdk.auth.signer.Aws4Signer - AWS4 String to sign: AWS4-HMAC-SHA256
20210305T014414Z
20210305/us-east-1/s3/aws4_request
9bfed5fd14903f65ac34647985e2c8a4bbe0fbf311982cfbeb2e44b2b58a2390
18:44:14.991 [HTTP-Dispatcher] WARN software.amazon.awssdk.http.apache.internal.utils.ApacheUtils - NoSuchMethodException was thrown when disabling normalizeUri. This indicates you are using an old version (< 4.5.8) of Apache http client. It is recommended to use http client version >= 4.5.9 to avoid the breaking change introduced in apache client 4.5.7 and the latency in exception handling. See https://github.com/aws/aws-sdk-java/issues/1919 for more information
18:44:15.098 [HTTP-Dispatcher] DEBUG software.amazon.awssdk.http.apache.internal.conn.SdkTlsSocketFactory - socket.getSupportedProtocols(): [TLSv1.3, TLSv1.2, TLSv1.1, TLSv1, SSLv3, SSLv2Hello], socket.getEnabledProtocols(): [TLSv1.3, TLSv1.2, TLSv1.1, TLSv1]
18:44:15.099 [HTTP-Dispatcher] DEBUG software.amazon.awssdk.http.apache.internal.conn.SdkTlsSocketFactory - TLS protocol enabled for SSL handshake: [TLSv1.2, TLSv1.1, TLSv1, TLSv1.3]
18:44:15.506 [HTTP-Dispatcher] DEBUG software.amazon.awssdk.http.apache.internal.net.SdkSslSocket - created: file-store.s3-server.dcstore.company.net/10.111.111.20:443

The warning message there is a little bit misleading and technically should be error in this particular case as this is a breaking change in httpclinet library which can cause unexpected behavior of the program. This dependency itself comes as a transitive dependency from aws-java-sdk. So, to get it fixed just follow recommendation provided in the warning message and explicitly define the required version of httpclinet in your project pom file:
<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpclient</artifactId>
<version>4.5.9</version>
</dependency>

Zuul: automatic rerouting incoming requests to other service instance in case of unavailable service

I have configured Zuul with Eureka in a way, that 3 identical instances of a service are working parallely. I am calling the gateway on the port 8400, which routes incoming requests to ports 8420, 8430 and 8440 in a round-robin manner. It works smoothly. Now, if I switching off one of the 3 services, a small amount of incoming requests will go wrong with the following exception:
com.netflix.zuul.exception.ZuulException: Filter threw Exception
=> 1: java.util.concurrent.FutureTask.report(FutureTask.java:122)
=> 3: hu.perit.spvitamin.core.batchprocessing.BatchProcessor.process(BatchProcessor.java:106)
caused by: com.netflix.zuul.exception.ZuulException: Filter threw Exception
=> 1: com.netflix.zuul.FilterProcessor.processZuulFilter(FilterProcessor.java:227)
caused by: org.springframework.cloud.netflix.zuul.util.ZuulRuntimeException: com.netflix.zuul.exception.ZuulException: Forwarding error
=> 1: org.springframework.cloud.netflix.zuul.filters.route.RibbonRoutingFilter.run(RibbonRoutingFilter.java:124)
caused by: com.netflix.zuul.exception.ZuulException: Forwarding error
=> 1: org.springframework.cloud.netflix.zuul.filters.route.RibbonRoutingFilter.handleException(RibbonRoutingFilter.java:198)
caused by: com.netflix.client.ClientException: com.netflix.client.ClientException
=> 1: com.netflix.client.AbstractLoadBalancerAwareClient.executeWithLoadBalancer(AbstractLoadBalancerAwareClient.java:118)
caused by: java.lang.RuntimeException: org.apache.http.NoHttpResponseException: scalable-service-2:8430 failed to respond
=> 1: rx.exceptions.Exceptions.propagate(Exceptions.java:57)
caused by: org.apache.http.NoHttpResponseException: scalable-service-2:8430 failed to respond
=> 1: org.apache.http.impl.conn.DefaultHttpResponseParser.parseHead(DefaultHttpResponseParser.java:141)
My Zuul routing looks like this:
### Zuul routes
zuul.routes.scalable-service.path=/scalable/**
#Authorization header will be forwarded to scalable-service
zuul.routes.scalable-service.sensitiveHeaders: Cookie,Set-Cookie
zuul.routes.scalable-service.serviceId=template-scalable-service
It takes a while until Eureka discovers the service is not available any more.
My question is: Is there a possibility, to configure Zuul so that in case of a NoHttpResponseException, it forwards the requests to another available instance in the pool?

Eureka, by default, requires lease to be renewed every 90s. That is, if a service instance doesn't get its lease renewed in 90s, Eureka server will evict the instance. In your case, the instance has not been evicted yet - the renew window for the instance was valid.
For this, you can decrease the renew duration through config setup at eureka client and eureka server as described here.
Note: If you hit the actuator /shutdown endpoint, the instance is immediately evicted

Finally I found the solution to the problem. The appropriate search phrase was 'fault tolerance'. The key is the autoretry config in the following application.properties file. The value of template-scalable-service.ribbon.MaxAutoRetriesNextServer must be set at least to 6 in case of 3 pooled services to achieve full fault tolerance. With that setup I can kill 2 of 3 services any time, no incoming request will go wrong. Finally I have set it to 10, there is no unnecessary increase of timeout, hystrix will break the line.
### Eureka config
eureka.instance.hostname=${hostname:localhost}
eureka.instance.instanceId=${eureka.instance.hostname}:${spring.application.name}:${server.port}
eureka.instance.non-secure-port-enabled=false
eureka.instance.secure-port-enabled=true
eureka.instance.secure-port=${server.port}
eureka.instance.lease-renewal-interval-in-seconds=5
eureka.instance.lease-expiration-duration-in-seconds=10
eureka.datacenter=perit.hu
eureka.environment=${EUREKA_ENVIRONMENT_PROFILE:dev}
eureka.client.serviceUrl.defaultZone=${EUREKA_SERVER:https://${server.fqdn}:${server.port}/eureka}
eureka.client.server.waitTimeInMsWhenSyncEmpty=0
eureka.client.registry-fetch-interval-seconds=5
eureka.dashboard.path=/gui
eureka.server.enable-self-preservation=false
eureka.server.expected-client-renewal-interval-seconds=10
eureka.server.eviction-interval-timer-in-ms=2000
### Ribbon
ribbon.IsSecure=true
ribbon.NFLoadBalancerPingInterval=5
ribbon.ConnectTimeout=30000
ribbon.ReadTimeout=120000
### Zuul config
zuul.host.connectTimeoutMillis=30000
zuul.host.socketTimeoutMillis=120000
zuul.host.maxTotalConnections=2000
zuul.host.maxPerRouteConnections=200
zuul.retryable=true
### Zuul routes
#template-scalable-service
zuul.routes.scalable-service.path=/scalable/**
#Authorization header will be forwarded to scalable-service
zuul.routes.scalable-service.sensitiveHeaders=Cookie,Set-Cookie
zuul.routes.scalable-service.serviceId=template-scalable-service
# Autoretry config for template-scalable-service
template-scalable-service.ribbon.MaxAutoRetries=0
template-scalable-service.ribbon.MaxAutoRetriesNextServer=10
template-scalable-service.ribbon.OkToRetryOnAllOperations=true
#template-auth-service
zuul.routes.auth-service.path=/auth/**
#Authorization header will be forwarded to scalable-service
zuul.routes.auth-service.sensitiveHeaders=Cookie,Set-Cookie
zuul.routes.auth-service.serviceId=template-auth-service
# Autoretry config for template-auth-service
template-auth-service.ribbon.MaxAutoRetries=0
template-auth-service.ribbon.MaxAutoRetriesNextServer=0
template-auth-service.ribbon.OkToRetryOnAllOperations=false
### Hystrix
hystrix.command.default.execution.timeout.enabled=false
Beside of this, I have a profile specific setup in application-discovery.properties
#Microservice environment
eureka.client.registerWithEureka=false
eureka.client.fetchRegistry=true
spring.cloud.loadbalancer.ribbon.enabled=true
I start my server in a docker container like this:
services:
discovery:
container_name: discovery
image: template-eureka
environment:
#agentlib for remote debugging
- JAVA_OPTS=-DEUREKA_SERVER=https://discovery:8400/eureka -agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=*:5005
- TEMPLATE_EUREKA_OPTS=-Dspring.profiles.active=default,dev,discovery
- EUREKA_ENVIRONMENT_PROFILE=dev
ports:
- '8400:8400'
- '5500:5005'
networks:
- back-tier-net
- monitoring
hostname: 'discovery'
See the complete solution in GitHub.

MarkLogic Java API deadlock detection

One of our application just suffered from some nasty deadlocks. I had quite a hard time recreating the problem because the deadlock (or stacktrace) did not show up immediately in my java application logs.
To my surprise the marklogic java api retries failing requests (e.g because of a deadlock). This might make sense, if your request is not a multi statement request, but otherwise i'm not sure if it does.
So lets stick with this deadlock problem. I created a simple code snippet in which i create a deadlock on purpose. The snippet creates a document test.xml and then tries to read and write from two different transactions, each on a new thread.
public static void main(String[] args) throws Exception {
final Logger root = (Logger) LoggerFactory.getLogger(Logger.ROOT_LOGGER_NAME);
final Logger ok = (Logger) LoggerFactory.getLogger(OkHttpServices.class);
root.setLevel(Level.ALL);
ok.setLevel(Level.ALL);
final DatabaseClient client = DatabaseClientFactory.newClient("localhost", 8000, new DatabaseClientFactory.DigestAuthContext("username", "password"));
final StringHandle handle = new StringHandle("<doc><name>Test</name></doc>")
.withFormat(Format.XML);
client.newTextDocumentManager().write("test.xml", handle);
root.info("t1: opening");
final Transaction t1 = client.openTransaction();
root.info("t1: reading");
client.newXMLDocumentManager()
.read("test.xml", new StringHandle(), t1);
root.info("t2: opening");
final Transaction t2 = client.openTransaction();
root.info("t2: reading");
client.newXMLDocumentManager()
.read("test.xml", new StringHandle(), t2);
new Thread(() -> {
root.info("t1: writing");
client.newXMLDocumentManager().write("test.xml", new StringHandle("<doc><t>t1</t></doc>").withFormat(Format.XML), t1);
t1.commit();
}).start();
new Thread(() -> {
root.info("t2: writing");
client.newXMLDocumentManager().write("test.xml", new StringHandle("<doc><t>t2</t></doc>").withFormat(Format.XML), t2);
t2.commit();
}).start();
TimeUnit.MINUTES.sleep(5);
client.release();
}
This code will produce the following log:
14:12:27.437 [main] DEBUG c.m.client.impl.OkHttpServices - Connecting to localhost at 8000 as admin
14:12:27.570 [main] DEBUG c.m.client.impl.OkHttpServices - Sending test.xml document in transaction null
14:12:27.608 [main] INFO ROOT - t1: opening
14:12:27.609 [main] DEBUG c.m.client.impl.OkHttpServices - Opening transaction
14:12:27.962 [main] INFO ROOT - t1: reading
14:12:27.963 [main] DEBUG c.m.client.impl.OkHttpServices - Getting test.xml in transaction 5298588351036278526
14:12:28.283 [main] INFO ROOT - t2: opening
14:12:28.283 [main] DEBUG c.m.client.impl.OkHttpServices - Opening transaction
14:12:28.286 [main] INFO ROOT - t2: reading
14:12:28.286 [main] DEBUG c.m.client.impl.OkHttpServices - Getting test.xml in transaction 8819382734425123844
14:12:28.289 [Thread-1] INFO ROOT - t1: writing
14:12:28.289 [Thread-1] DEBUG c.m.client.impl.OkHttpServices - Sending test.xml document in transaction 5298588351036278526
14:12:28.289 [Thread-2] INFO ROOT - t2: writing
14:12:28.290 [Thread-2] DEBUG c.m.client.impl.OkHttpServices - Sending test.xml document in transaction 8819382734425123844
Neither t1 or t2 will get commited. MarkLogic logs confirm that there actually is a deadlock:
==> /var/opt/MarkLogic/Logs/8000_AccessLog.txt <==
127.0.0.1 - admin [24/Nov/2018:14:12:30 +0000] "PUT /v1/documents?txid=5298588351036278526&category=content&uri=test.xml HTTP/1.1" 503 1034 - "okhttp/3.9.0"
==> /var/opt/MarkLogic/Logs/ErrorLog.txt <==
2018-11-24 14:12:30.719 Info: Deadlock detected locking Documents test.xml
This would not be a problem, if one of the requests would fail and throw an exception, but this is not the case. MarkLogic Java Api retries every request up to 120 seconds and one of the updates timeouts after like 120 seconds or so:
Exception in thread "Thread-1" com.marklogic.client.FailedRequestException: Service unavailable and maximum retry period elapsed: 121 seconds after 65 retries
at com.marklogic.client.impl.OkHttpServices.putPostDocumentImpl(OkHttpServices.java:1422)
at com.marklogic.client.impl.OkHttpServices.putDocument(OkHttpServices.java:1256)
at com.marklogic.client.impl.DocumentManagerImpl.write(DocumentManagerImpl.java:920)
at com.marklogic.client.impl.DocumentManagerImpl.write(DocumentManagerImpl.java:758)
at com.marklogic.client.impl.DocumentManagerImpl.write(DocumentManagerImpl.java:717)
at Scratch.lambda$main$0(scratch.java:40)
at java.lang.Thread.run(Thread.java:748)
What are possible ways to overcome this problem? One way might be to set a maximum time to live for a transaction (like 5 seconds), but this feels hacky and unreliable. Any other ideas? Are there any other settings i should check out?
I'm on MarkLogic 9.0-7.2 and using marklogic-client-api:4.0.3.
Edit: One way to solve the deadlock would be by syncronizing the calling function, this is actually the way i solved it in my case (see comments). But i think the underlying problem still exists. Having a deadlock in a multi statement transaction should not be hidden away in a 120 second timeout. I rather have a immediately failing request than a 120 second lock on one of my documents + 64 failing retries per thread.

Deadlocks are usually resolvable by retrying. Internally, the server does a inner-retry loop because usually deadlocks are transient and incidental, lasting a very short time. In your case you have constructed a case that will never succeed with any timeout that's equal for both threads.
Deadlocks can be avoided at the application layer by avoiding multi-statement transactions when using the REST API. (which is what the Java api uses).
Multi statement transactions over REST cannot be implemented 100% safely due to the client's responsibility to manage the transaction ID and the server's inability to detect client-side errors or client-side identity. Very subtle problems can and do occur unless you are aggressively proactive wrt handling errors and multithreading. If you 'push' the logic to the server (xquery or javascript) the server is able to manage things much better.
As for if its 'good' or not for the Java API to implement retries for this case, that's debatable either way. (The compromise for an seemingly easy-to-use interface is that many things that would otherwise be options are decided for you as a convention. There's generally no one-size-fits-all answer. In this case I am presuming the thought was that a deadlock is more likely caused by independant code/logic by 'accident' as opposed to identical code running in tangent -- a retry in that case would be a good choice. In your example its not, but then an earlier error would still fail predictably until you change your code to 'not do that' ).
If it doesn't already exist, a feature request for a configurable timeout and retry behaviour does seem a reasonable request. I would recommend, however, to attempt to avoid any REST calls that result in an open transaction -- inherently that is problematic, particularly if you don't notice the problem upfront (then its more likely to bite you in production). Unlike JDBC, which keeps a connection open so that the server can detect client disconnects, HTTP and the ML Rest API do not -- which leads to a different programming model then traditional database coding in java.

Connecting to dcm4chee using dcm4che from a JAVA program

Update
I dug deeper in dcm4che's source code and found that an IncompatibleConnectionException is thrown if either
a connection is "not installed"
or the types of protocols are not set or don't match.
I don't know what it means that a connection is "installed" but this flag can be set manually, so I set it for both the local and remote connections to true (even checked them with getInstalled() whether they are "installed" - and yes they are now - previously this property was null).
And as to the protocols, they weren't specified, so for both connections I set them to DICOM.
Results: I still get the same Exception.
I'd like to establish a DICOM association between dcm4chee (2.18.3) and my JAVA application using the dcm4che (5.12.0) toolkit.
The problem is that it doesn't seem to be any documentation available on how to use dcm4che in a JAVA application, so all I can do is read dcm4che's source code and try to figure out what its classes and methods are for, but I'm stuck. If someone already has a working example it would be very helpful.
So far I have:
import org.dcm4che3.net.ApplicationEntity;
import org.dcm4che3.net.Association;
import org.dcm4che3.net.Connection;
import org.dcm4che3.net.Device;
import org.dcm4che3.net.pdu.AAssociateRQ;
import org.dcm4che3.net.pdu.PresentationContext;
...
ApplicationEntity locAE = new ApplicationEntity();
locAE.setAETitle("THIS_JAVA_APP");
Connection localConn = new Connection();
localConn.setCommonName("loc_conn");
localConn.setHostname("localhost");
localConn.setPort(11112);
localConn.setProtocol(Connection.Protocol.DICOM);
localConn.setInstalled(true);
locAE.addConnection(localConn);
ApplicationEntity remAE = new ApplicationEntity();
remAE.setAETitle("DCM4CHEE");
Connection remoteConn = new Connection();
remoteConn.setCommonName("rem_conn");
remoteConn.setHostname("localhost");
remoteConn.setPort(11112);
remoteConn.setProtocol(Connection.Protocol.DICOM);
remoteConn.setInstalled(true);
remAE.addConnection(remoteConn);
AAssociateRQ assocReq = new AAssociateRQ();
assocReq.setCalledAET(remAE.getAETitle());
assocReq.setCallingAET(locAE.getAETitle());
assocReq.setApplicationContext("1.2.840.10008.3.1.1.1");
assocReq.setImplClassUID("1.2.40.0.13.1.3");
assocReq.setImplVersionName("dcm4che-5.12.0");
assocReq.setMaxPDULength(16384);
assocReq.setMaxOpsInvoked(0);
assocReq.setMaxOpsPerformed(0);
assocReq.addPresentationContext(new PresentationContext(
1, "1.2.840.10008.1.1", "1.2.840.10008.1.2"));
Device device = new Device("device");
device.addConnection(localConn);
device.addApplicationEntity(locAE);
Association assoc = locAE.connect(remAE, assocReq);
but I don't know whether I'm on the right path doing it.
The error I get:
org.dcm4che3.net.IncompatibleConnectionException: No compatible connection to DCM4CHEE available on THIS_JAVA_APP
at org.dcm4che3.net.ApplicationEntity.findCompatibelConnection(ApplicationEntity.java:646)
at org.dcm4che3.net.ApplicationEntity.connect(ApplicationEntity.java:651)

Could it be, that You are missing a Device instance from Your setup? It seems, that You need a Device, to which You attach both ApplicationEntity and Connection.
Looking at FindSCU.java source from dcm4che source.
private final Device device = new Device("findscu");
private final ApplicationEntity ae = new ApplicationEntity("FINDSCU");
private final Connection conn = new Connection();
public FindSCU() throws IOException {
device.addConnection(conn);
device.addApplicationEntity(ae);
ae.addConnection(conn);
}
I also think, that maybe the local Connection object can be instantiated without any parameters as the FindSCU example here demonstrates. Maybe the parameters are confusing it somehow, especially considering, that you have both local and remote connections pointing to localhost:11112.
But yes, one has to agree, that the documentation for dcm4che3 API is totally inadequate.

Here is the working code: (I don't know if it's the minimal solution, feel free to experiment with it...)
ApplicationEntity locAE = new ApplicationEntity();
locAE.setAETitle("THIS_JAVA_APP");
locAE.setInstalled(true);
Connection localConn = new Connection();
localConn.setCommonName("loc_conn");
localConn.setHostname("localhost");
localConn.setPort(11112);
localConn.setProtocol(Connection.Protocol.DICOM);
localConn.setInstalled(true);
locAE.addConnection(localConn);
ApplicationEntity remAE = new ApplicationEntity();
remAE.setAETitle("DCM4CHEE");
remAE.setInstalled(true);
Connection remoteConn = new Connection();
remoteConn.setCommonName("rem_conn");
remoteConn.setHostname("localhost");
remoteConn.setPort(11112);
remoteConn.setProtocol(Connection.Protocol.DICOM);
remoteConn.setInstalled(true);
remAE.addConnection(remoteConn);
AAssociateRQ assocReq = new AAssociateRQ();
assocReq.setCalledAET(remAE.getAETitle());
assocReq.setCallingAET(locAE.getAETitle());
assocReq.setApplicationContext("1.2.840.10008.3.1.1.1");
assocReq.setImplClassUID("1.2.40.0.13.1.3");
assocReq.setImplVersionName("dcm4che-5.12.0");
assocReq.setMaxPDULength(16384);
assocReq.setMaxOpsInvoked(0);
assocReq.setMaxOpsPerformed(0);
assocReq.addPresentationContext(new PresentationContext(
1, "1.2.840.10008.1.1", "1.2.840.10008.1.2"));
Device device = new Device("device");
device.addConnection(localConn);
device.addApplicationEntity(locAE);
Executor exec = (Runnable command) -> {};
device.setExecutor(exec);
Association assoc = locAE.connect(localConn, remoteConn, assocReq);
And the relevant dcm4chee log:
2018-03-02 23:21:42,832 INFO THIS_JAVA_APP->DCM4CHEE (TCPServer-1) [org.dcm4cheri.net.FsmImpl] received AAssociateRQ
appCtxName: 1.2.840.10008.3.1.1.1/DICOM Application Context Name
implClass: 1.2.40.0.13.1.3
implVersion: dcm4che-5.12.0
calledAET: DCM4CHEE
callingAET: THIS_JAVA_APP
maxPDULen: 16378
asyncOpsWindow:
pc-1: as=1.2.840.10008.1.1/Verification SOP Class
ts=1.2.840.10008.1.2/Implicit VR Little Endian
2018-03-02 23:21:42,843 INFO THIS_JAVA_APP->DCM4CHEE (TCPServer-1) [org.dcm4cheri.net.FsmImpl] sending AAssociateAC
appCtxName: 1.2.840.10008.3.1.1.1/DICOM Application Context Name
implClass: 1.2.40.0.13.1.1.1
implVersion: dcm4che-1.4.34
calledAET: DCM4CHEE
callingAET: THIS_JAVA_APP
maxPDULen: 16352
asyncOpsWindow:
pc-1: 0 - acceptance
ts=1.2.840.10008.1.2/Implicit VR Little Endian
After you have the association, see this other post for how to perform a C-FIND.

Edit
Apparently, I solved the problem. Changing the executor from
Executor exec = (Runnable command) -> {};
device.setExecutor(exec);
to
ExecutorService executorService = Executors.newSingleThreadExecutor();
ScheduledExecutorService scheduledExecutorService = Executors.newSingleThreadScheduledExecutor();
device.setExecutor(executorService);
device.setScheduledExecutor(scheduledExecutorService);
made it so my application correctly received the association response from the server. This might serve as reference for someone else.
Thank you for sharing your code. It was really helpful to me.
Original Post
I am unable to perform the connection with a code similar to the solution you proposed. I am trying to request an association with a dcm4chee-arc-light with dcm4che (both 5.14.1), and I have as it follows:
Device device = new Device(deviceName);
ApplicationEntity locAE = new ApplicationEntity(localAE);
Connection conn = new Connection();
Connection remote = new Connection();
AAssociateRQ rq = new AAssociateRQ();
device.addConnection(conn);
device.addApplicationEntity(locAE);
locAE.addConnection(conn);
ApplicationEntity remAE = new ApplicationEntity();
remAE.setAETitle(remoteAE);
remote.setCommonName("rem_conn");
remote.setHostname(remoteIP);
remote.setPort(remotePort);
remote.setProtocol(Connection.Protocol.DICOM);
remAE.addConnection(remote);
rq.setCalledAET(remAE.getAETitle());
rq.setCallingAET(locAE.getAETitle());
rq.setApplicationContext("1.2.840.10008.3.1.1.1");
rq.setImplClassUID("1.2.40.0.13.1.3");
rq.setImplVersionName("dcm4che-5.14.1");
rq.setMaxPDULength(16384);
rq.setMaxOpsInvoked(0);
rq.setMaxOpsPerformed(0);
rq.addPresentationContext(new PresentationContext(
1, "1.2.840.10008.5.1.4.1.2.2.1", "1.2.840.10008.1.2"));
Executor exec = (Runnable command) -> {};
device.setExecutor(exec);
//Opens association and connects to remote server
Association as = locAE.connect(conn, remote, rq);
But when trying to connect to a remote AET, it doesn't seem to receive the AAssociation response from the remote AET. My Java application hangs in Sta5 (waiting for association response) while the server hangs in Sta6 (ready for data transfer).
Java log:
[main] INFO org.dcm4che3.net.Connection - Initiate connection from 0.0.0.0/0.0.0.0:0 to localhost:11112
[main] INFO org.dcm4che3.net.Connection - Established connection Socket[addr=localhost/127.0.0.1,port=11112,localport=50101]
[main] DEBUG org.dcm4che3.net.Association - /127.0.0.1:50101>localhost/127.0.0.1:11112(1): enter state: Sta4 - Awaiting transport connection opening to complete
[main] INFO org.dcm4che3.net.Association - DEVICEAE->DCMQRSCP(1) << A-ASSOCIATE-RQ
[main] DEBUG org.dcm4che3.net.Association - A-ASSOCIATE-RQ[
calledAET: DCMQRSCP
callingAET: DEVICEAE
applicationContext: 1.2.840.10008.3.1.1.1 - DICOM Application Context Name
implClassUID: 1.2.40.0.13.1.3
implVersionName: dcm4che-5.14.1
maxPDULength: 16378
maxOpsInvoked/maxOpsPerformed: 1/1
PresentationContext[id: 1
as: 1.2.840.10008.5.1.4.1.2.2.1 - Study Root Query/Retrieve Information Model - FIND
ts: 1.2.840.10008.1.2 - Implicit VR Little Endian
]
]
[main] DEBUG org.dcm4che3.net.Association - DEVICEAE->DCMQRSCP(1): enter state: Sta5 - Awaiting A-ASSOCIATE-AC or A-ASSOCIATE-RJ PDU
Server log:
19:11:29,397 INFO - Accept connection Socket[addr=/127.0.0.1,port=50101,localport=11112]
19:11:29,397 DEBUG - /127.0.0.1:11112<-/127.0.0.1:50101(3): enter state: Sta2 - Transport connection open
19:11:29,416 INFO - DCMQRSCP<-DEVICEAE(3) >> A-ASSOCIATE-RQ
19:11:29,416 DEBUG - A-ASSOCIATE-RQ[
calledAET: DCMQRSCP
callingAET: DEVICEAE
applicationContext: 1.2.840.10008.3.1.1.1 - DICOM Application Context Name
implClassUID: 1.2.40.0.13.1.3
implVersionName: dcm4che-5.14.1
maxPDULength: 16378
maxOpsInvoked/maxOpsPerformed: 1/1
PresentationContext[id: 1
as: 1.2.840.10008.5.1.4.1.2.2.1 - Study Root Query/Retrieve Information Model - FIND
ts: 1.2.840.10008.1.2 - Implicit VR Little Endian
]
]
19:11:29,419 DEBUG - DCMQRSCP<-DEVICEAE(3): enter state: Sta3 - Awaiting local A-ASSOCIATE response primitive
19:11:29,419 INFO - DCMQRSCP<-DEVICEAE(3) << A-ASSOCIATE-AC
19:11:29,419 DEBUG - A-ASSOCIATE-AC[
calledAET: DCMQRSCP
callingAET: DEVICEAE
applicationContext: 1.2.840.10008.3.1.1.1 - DICOM Application Context Name
implClassUID: 1.2.40.0.13.1.3
implVersionName: dcm4che-5.14.1
maxPDULength: 16378
maxOpsInvoked/maxOpsPerformed: 1/1
PresentationContext[id: 1
result: 0 - acceptance
ts: 1.2.840.10008.1.2 - Implicit VR Little Endian
]
]
19:11:29,427 DEBUG - DCMQRSCP<-DEVICEAE(3): enter state: Sta6 - Association established and ready for data transfer
I feel like I am missing something, but I cannot find the source of the problem. Any help is appreciated, as I am still new to dcm4che and DICOM protocol.
Thank you.