java - JMS consume multiple topics -

-

i new java , working on project consumes multiple (different) topics , sends server. wondering best way handling multiple topics is.

from understand each consumer tied 1 topic, if had consume multiple topics need 1 consumer each different topic. since consumer makes blocking call need invoke thread per consumer consume these topics in parallel.

and if wanted improve throughput further practice have 1 boss thread per consumer (attached topic) , allow each boss thread setup worker threads improve performance accordingly?

please advice if practice , if not other alternative options? , there known design patterns handle problem

why chose consumer model instead of listener model?

i have 1 more constraint is, after consumer receives message needs send message receiving server. if receiving server down (during new version push) have pause consuming messages until receiving server up. in case having message listener wouldn't because wouldn't able pause listener when receiving server down. right when or there way pause listener , stop consuming messages until receiving server up?

the way go use listener feature.

your object implements messagelistener interface , add consumer message listener. in case client library handle threading in reading messages queue , despatching them listeners.

import javax.jms.connection; import javax.jms.destination; import javax.jms.message; import javax.jms.messageconsumer; import javax.jms.messagelistener; import javax.jms.session;  import org.apache.activemq.activemqconnectionfactory;  public class mymessageconsumer implements messagelistener {      public static void main() {         try {              mymessageconsumer mymessageconsumer = new mymessageconsumer();              // example using activemq client library             activemqconnectionfactory connectionfactory = new activemqconnectionfactory("nio://localhost:61616");             connection connection = connectionfactory.createconnection();             connection.start();              session session = connection.createsession(false, session.auto_acknowledge);              destination destination1 = session.createqueue("mytopic1");             messageconsumer consumer1 = session.createconsumer(destination1);             consumer1.setmessagelistener(mymessageconsumer);              destination destination2 = session.createqueue("mytopic2");             messageconsumer consumer2 = session.createconsumer(destination2);             consumer2.setmessagelistener(mymessageconsumer);          } catch (exception e) {             system.out.println("caught: " + e);             e.printstacktrace();         }     }      @override     public void onmessage(message message) {         // handle messages here     } }

session transactions

in option, use transacted messages , deliver message if session.rollback() called. acknowledge() when operation successful or rollback() when not.

package io.bessel.test;

import javax.jms.connection; import javax.jms.destination; import javax.jms.jmsexception; import javax.jms.message; import javax.jms.messageconsumer; import javax.jms.messagelistener; import javax.jms.session; import javax.jms.textmessage;  import org.apache.activemq.activemqconnectionfactory;  public class mymessageconsumer implements messagelistener {      public static void main(string ... arguments) {         try {             // example using activemq client library             activemqconnectionfactory connectionfactory = new activemqconnectionfactory("nio://localhost:61616");             connection connection = connectionfactory.createconnection();             connection.start();              session session = connection.createsession(true, session.session_transacted);              mymessageconsumer mymessageconsumer = new mymessageconsumer(session);              destination destination1 = session.createqueue("mytopic1");             messageconsumer consumer1 = session.createconsumer(destination1);             consumer1.setmessagelistener(mymessageconsumer);              destination destination2 = session.createqueue("mytopic2");             messageconsumer consumer2 = session.createconsumer(destination2);             consumer2.setmessagelistener(mymessageconsumer);          } catch (exception e) {             system.out.println("caught: " + e);             e.printstacktrace();         }     }      private final session session;      public mymessageconsumer(session session) {         this.session = session;     }      public void onmessage(message message) {         if (message instanceof textmessage) {             try {                 string text = ((textmessage) message).gettext();                 system.out.println(string.format("received message: %s", text));                 this.session.rollback();              } catch (jmsexception e) {                 e.printstacktrace();             }         }     }  }

Comments

Post a Comment

Popular posts from this blog

c# - How Configure Devart dotConnect for SQLite Code First? -

-
can configure following sample code ? when run following code, error : no entity framework provider found ado.net provider invariant name 'devart.data.sqlite' setting in machine.config <system.data> <dbproviderfactories> <add name="dotconnect sqlite" invariant="devart.data.sqlite" description="devart dotconnect sqlite" type="devart.data.sqlite.sqliteproviderfactory, devart.data.sqlite, version=4.6.287.0, culture=neutral, publickeytoken=09af7300eec23701" /> </dbproviderfactories> </system.data> after add below block code in app.config <?xml version="1.0"?> <configuration>   <configsections> <!-- more information on entity framework configuration, visit http://go.microsoft.com/fwlink/?linkid=237468 --> <section name="entityframework" type="system.data.entity.internal.configfile.entityframeworksection, entit...
Read more

java - Copying object fields -

-
what best way of copying classes when need have 2 independent variables? have simple class: public class myclass { boolean = false; string b= "not empty"; } do need make method : assign(myclass data ) { a= data.a; b= data.b; } is there automatic method copy (duplicate) objects in java? do need make method : pretty close. instead of making method, should make constructor. such constructors called copy constructor , , create them this: myclass(myclass data) { = data.a; b = data.b; } and create copy of instance, use constructor this: myclass obj1 = new myclass(); myclass obj2 = new myclass(obj1); copy constructor can tedious : using copy constructor create deep-copy can tedious, when class has mutable fields. in case, assignment create copy of reference, , not object itself. have create copy of fields (if want deep copy). can go recursive. a better way create deep copy serialize , deserialize object. why not use clone()? ...
Read more

c++ - Clear the memory after returning a vector in a function -

-
i have function processes , stores lot of data in , returns results vector of class. amount of data stored in function tremendous , want clear storage memory of function after finished job. necessary (does function automatically clear memory) or should clear memory function? update: vector<customers> process(char* const *filename, vector<int> id) { vector<customers> list_of_customers; (perform actions) return list_of_customers; } variables defined locally within function automatically released @ end of function scope. destructors objects called, should free memory allocated objects (if objects coded correctly). example of such object std::vector . anything you've allocated new must have corresponding delete release storage. try avoid doing own allocation , use raii instead, i.e. containers or smart pointers.
Read more