Spring Framework JMS versus AMQP, Enterprise Integration Patterns (EIP), and Spring Integration versus Apache Camel

Q. Why do you need AMQP when there is JMS?
A. AMQP stands for Advanced Message Queuing Protocol, and was developed to address the problem of interoperability by creating a standard for how messages should be structured and transmitted between platforms the same way as SMTP, HTTP, FTP, etc. have created interoperable systems. This standard binary wire level protocol for messaging would therefore allow hetrogeneous disparate systems between and within companies to exchange messages regrdless of the message broker vendor or platform. 


RabbitMQ, Apache Qpid, StormMQ, etc are open source message broker softwares (i.e. MOM - message-oriented middlewares) that implements the Advanced Message Queuing Protocol (AMQP). 

Q. How does AMQP differ from JMS?
A. JMS is a standard messaging API for the Java platform. It provides a level of abstraction that frees developers from having to worry about specific implementation and wire protocols. This is similar to the JDBC API that allows you to easily switch databases. With JMS, you can switch from one JMS complian message broker (e.g. Web Methods) with another one (e.g. MQSeries or WebspehreMQ) with little or no changes to your source code. It also provides interoperability between other JVM based languages like Scala and Groovy. Altough JMS brokers can be used in .NET applications,  the whole JMS specification does not guarantee interoperability, and integration between Java to .NET  or Java to Ruby, is proprietary and can be quite tricky. In scenarios where you want to send a message from a Java based message producer to a .NET based message consumer, then you need a message based cross platform interoperability that is what AMQP does. With AMQP, you can use any AMQP compliant client library, and AMQP compliant message broker.


Q. What are the different alternatives to integrate various enterprise systems?
A.

Alternative 1: Custom Solution. Implement an individual solution that works for your problem without separating problems into little pieces. For example, use Apache CXF for Web services, overnight batch job runs to load data feeds, JMS for messaging, etc. This is more suited for small use cases. This has higher maintainability and developer effort. The developer has to handle errors, service retries, transactional management, etc. This is suited if you want to integrate one or two applications using one or two protocols. 


Alternative 2: Using an (opensource) integration framework like Spring Integration or Apache Camel. This helps you integrate systems in a standardised way adhering to the enterprise integration patterns (EIP). Apache Camel is a light weight integration framework that allows you to use HTTP, FTP, JMS, EJB, JPA, RMI, JMS, JMX, LDAP, and Netty to name a few. You use the same concept to integrate various protocols in Apache Camel. This increases maintainability and reduces developer effort. This is more suited  if you want to integrate several applications with different protocols.


Alternative 3: Using an ESB (Enterprise Service Bus) to integrate your applications. For example, Oracle Service Bus, TIBCO ESB, webMethods, etc. Under the hood, the ESB also uses an integration framework and provide more services and management functionalities like monitoring, high availability, clustering, graphical user inteface for routing and configuring, etc. Usually, an ESB is a complex and powerful product with a higher learning curve. Suited for very large integration projects. Projects requiring BPM (Business Process Managemnt) integration and other integrated services like monitoring, clustering, etc.



Q. What is an architecture that enables separate applications to work together, but in a de-coupled fashion such that applications can be easily added or removed without affecting the others?
A. This is achieved via a Message Oriented Middleware (aka a message bus).



Q. How can the caller be sure that exactly one receiver will receive the document or perform the call?
A. Use the point-to-point channel


Q. How can the sender broadcast an event to all interested receivers?
A. Use the publish subscribe channel.

Q. What will the messaging system do with a message it cannot deliver?
A. Put it on the dead letter channel.

Q. How can the sender make sure that a message will be delivered, even if the messaging system fails?
A. Use the "guaranteed delivery" mechanism.


Q. What are the diffrent ways to route messages?
A. EIP (Enterprise Integration Patterns) define different types of rules based routing to solve common enterprise intergration problems. Like GoF design patterns is the EIP allows integration architects and designers to share a common vocabulary.

  1. Content based routing uses XPath predicates to route messages based on the message content.  Content enricher supplements the original message with additional relevant information recieved from the other sources.
  2. Splitter  provides the EIP service engine to split messages into separate parts based on the XPATH expression. Splits a composite message into a series of individual message parts.
  3. Split Aggregator is used to collect and store individual message parts until a complete set of co-related message parts has been recieved. Once all the related parts have been recieved, they are aggregated to form a single message.
  4. Static Recipent List based routing inspects an incoming message, and depending upon the number of recipients mentioned in the list, it can forward the message to all channels associated with the "recipients list".  
  5. A Resquencer is used to get a stream of related but out of sequence messages back into correct order. Because individual messages may follow different routes, some messages are likely to pass through the processing steps sooner than others, resulting in the messages getting out of order. A resequencer usually does not modify the message contents.
  6. A message filter is a processor that eliminates undesired messages based on specific criteria. Filtering is controlled by specifying a predicate in the filter: when the predicate is true, the incoming message is allowed to pass; otherwise, it is blocked. A message filter usually does not modify the message contents.


Q. How would you deal with large message volumes?
A.
  • You can reduce the data volume with the use of "Claim Check" pattern, which allows you to replace message content with a claim check (a unique key), which can be used to retrieve the message content at a later time. The message content will be stored temporarily in a persistent store like a database or file system. This pattern is very useful when message content is very large and not all components require all information.
  • A Content Filter can be used to remove unwanted data elements from a message. It is useful to simplify the structure of the message. Very often, messages are represented as tree structures containing many levels of nested, repeating groups because they are modeled after generic, normalized database structures. Very often, this level of nesting is superfluous and a Content Filter can be used to 'flatten' the hierarchy into a simple list of elements that can be more easily understood and processed by other systems.


Q. How would you go about choosing between Spring Integration and Apache Camel to solve common integration problems?
A. 

Spring Integration provides an extension to the Spring programming model to support the well-known Enterprise Integration Patterns while building on the Spring Framework's existing support for enterprise integrationSpring Integration is more suited, if you already have got a Spring project and need to add some integration stuff to it. It requires almost no additional effort to learn Spring Integration if you know Spring itself. Nevertheless, Spring Integration only offers very rudimenary support for technologies such as AMQP, Spring Application Events, Feeds (e.g, RSS/ATOM), File, FTP, FTPS, SFTP, Gemfire, Groovy, HTTP (REST), TCP/IP, JDBC, JMS, JMX, Mail (IMAP/IDLE/POP3), MongoDB, Redis, RMI, Twitter, Web Services (SOAP), and XMPP. Integrations are implemented by writing a lot of XML based DSL(without a real DSL - Domain Specific Language). Spring Integration can be though of as a catch up game to Apache Camel as JavaEE did a catch up with Spring.

Apache Camel is a powerful open source integration framework based on known Enterprise Integration Patterns with powerful support for integration with core Spring. Apache Camel is almost identical to Mule ESB, and offers many components (even more than Spring Integration) for almost every technology you could think of. If there is no component available, you can create your own component very easily starting with a Maven archetype. Camel also supports a Spring based XML configuration as well as a "DSL" for Java, Groovy, and Scala. The benefits of using the Java DSL is that your IDE can auto complete your code as you start typing, rather than having to mess around with buckets of XML. The Java DSL is also very expressive as you can mix and match your own code within the language for Expression or Predicate evaluations. So, it has better readability and there are commercial tools like "Fuse IDE" for generating XML based DSL code.

Mule ESB is another choice and as the name suggests, it is an ESB including additional bells and whistles. This can be compared to "Apache ServiceMix", which is an extension to Apache Camel. Mule also only offers XML based DSL. The Mule Studio is a visual designer. Mule does provide proprietary connector support for systems like SAP, Tibco Rendevous, PayPal, Sibel CRM, IBM's CICS, etc.

So, the decision is not clear cut and it depends on your needs.



Labels: ,

Labels

.equals = operator abstract class abstract method abstract window toolkit Access Modifiers accessing java beans accessing javabeans action events actionperformed active addition Advanced Advanced Overloading AdvJavaBooks Agile development ajax alive AMQP and Android anonymous class anonymous inner class Ant ant tutorials anti patterns antipatterns Apache Camel api for jsp api for servlet api for servlets api jsp application context application scope application session Apps Architecture are you eligible for the ocmjd certificaiton are you eligible for the scjd certification arithmetic operator arpanet array construction array declaration array initialization array list array to list conversion arraylist arraylist of strings arraylist of types arraylist questions arraylists Arrays arrays in java ask for help assert assert in java assertions assertions in java assignment assignment operator Atlassian attribute visibility authentication authorization autoboxing autounboxing awt AWT Event Handling awt interview questions AWT Layouts awt questions awt questions and answers backed collection backed collections Basic Basics of event handling bean attributes bean properties bean scope Beginner best practices BigData blocked books boxing buffer size bufferedreader bufferedwriter business delegate business delegate pattern calendar case statement casting in java casting interview questions chapter review choosing a java locking mechanism choosing a locking mechanism choosing a thread locking mechanism class inside a method class questions class with no name class without a name classes interview questions Clipboard closing jsp tags code snap coding cohesion collection generics collection interview questions collection methods collection of types collection questions collection searching collection types Collections Collections Framework collections interview questions collections sorting colors in java swings colors in swing command line arguments communication between threads comparable comparator comparison operators compiling java classes computers concurrency example and tutorial config Configuration ConnectionPooling constructor creation constructor interview questions constructor overloading constructors in java containers contents of deployment descriptor contents of web.xml context context scope converting array to list converting list to array core java core java interview core java interview question core java interview questions core java questions core java; core java; object oriented programming CoreJava CoreJavaBooks CORS coupling create threads creating 2 dimensional shapes creating 2D shapes creating a frame creating a jframe creating a thread creating an arraylist creating an inner class creating an interface creating java beans creating java threads creating javabeans creating threads creating threads in java CSS cURL currency current thread determination custom tag library custom taglib custom taglibs custom tags CVS dao dao design pattern dao factory pattern dao pattern data access object data access object pattern data structure and algorithm database date and time tutorial date format dateformat dates deadlock deadlocks debugging Declarations decorator pattern decrement default deleting sessions deploy web app deployment deployment descriptor deployment descriptor contents deployment of web application deserialization deserialize design pattern design pattern interview questions design patterns Designpatterns destory method destroy destroying sessions determining current thread determining the current thread Developer Differences different types of collections display stuff in a frame displaying images displaying images in java swings displaying images in swings displaying text in a component division do while loop doget dohead dopost doput DOS Downloads drawing a line drawing an ellipse drawing circles drawing ellipses drawing lines Drools tutorial eBooks Eclipse Eclipse Tutorial Encapsulation encapsulation in java enhanced for loop entity facade pattern enumerations enumerations in java enums equal to equals equals comparison error and exception error codes error handling in servlets error page event handling in swings event listeners exam prep tips example servlet Examples exception exception handling exception handling in servlets exception handling interview questions exception handling questions Exceptions exceptions in java exceptions in web applications explicit locking explicit locking of objects file file navigation filereader filewriter final class final method FireBug first servlet FIX protocol FIX Protocol interview questions FIX protocol tutorial font fonts for each loop for loop form parameters form values formatting forwarding requests frame frame creation frame positioning frame swings front controller front controller design pattern front controller pattern fundamental.Java FXML Games garbage collection garbage collection interview questions garbage collection questions garbage collector gc gc questions general generic Generics generics collections Geo get get set methods getattribute getting bean property getting form values getting form values in servlet getting scwcd certified getting servlet initialization parameters getting sun certified Google Graphics2D gregorian calendar handling strings in java hash hash map hash table hashcode hashmap hashset hashtable head head request HeadFirst heap heaps hibernate hibernate interview questions hibernate interview questions and answers hibernate questions hibernate questions and answers Hibernate Tutorial HibernateBooks homework How To HTML HTML and JavaScript html form http request http request handling http request header http request methods http request servlet http request type http session httprequest httprequest methods httpservlet httpservlet interview questions httpservlet interview questions with answers httpsession httpsession interview questions httpsession questions HttpSessionActivationListener HttpSessionAttributeListener HttpSessionBindingListener if if else if else block if else statement Image IO implementing an interface Implicit objects increment info inheritance inheritance in java init init method Initialization Blocks inner class inner class inside a method inner classes innerclass installation instanceof instanceof operator IntelliJ interaction between threads interface interface interview interface questions interfaces interfaces in java interfaces interview questions internet history interrupting a thread interrupting threads Interview interview questions interview questions on design patterns interview questions on exception handling interview questions on java collections interview questions on serialization introduction to java threads introduction to jsps introduction to threading introduction to threads invalidating session Investment Banking IO Package iscurrentthread iterator J2EE j2ee api j2ee design pattern j2ee design pattern interview questions j2ee design patterns j2ee hibernate interview questions j2ee history j2ee interview j2ee interview questions j2ee mvc j2ee mvc pattern j2ee programmer j2ee questions j2ee servlet api j2ee session j2ee struts interview questions java java 5 tutorial Java 8 java arrays java assertions java assignments java awt questions java bean java bean scope java beans java beginners tutorial Java career java certification Java Class java collection interview questions and answers java collection tutorial java collections java collections interview questions java constructors java currency Java CV java data base connectivity java database connectivity java database connectivity interview questions and answers java dates java design pattern java design patterns java developer certification Java EE java encapsulation java enums java event listeners java exceptions java formatting java garbage collection java garbage collector java gc java heap Java I/O java inheritance java input output Java Interface Java Interview Java Interview Answers Java Interview Questions Java Introduction java io java IO tutorial java iterator java jdbc Java JSON tutorial Java Key Areas java lists java literals java locks nested Java Media Framework java methods java multithreading Java multithreading Tutorials java nested locks java networking tutorial java numbers Java Objects java operators java overloading java parsing Java Programming Tutorials java race conditions java regex java regular expressions Java resume java scjp java searching java serialization java server pages java server pages api java server pages questions java spring interview questions. j2ee spring interview questions java stack java strings java swing java swing event listeners java swing frame java swing images java swings java swings images java thread explicit locking java thread lock scope java thread locking java thread locking mechanism java thread locking objects java threads java threads race condition java tips java tokenizing Java Tools Java Tutorial java ui questions Java Utilities java variables java wrappers Java xml tutorial java.lang java8 javabean javabean accessing javabean scope JavaBeans javac JavaEE JavaFX JavaFX 3D JavaFX 8 JavaOne JavaScript JavaTips JDBC jdbc driver jdbc example jdbc interview questions jdbc interview questions and answers jdbc interview questions with answers jdbc sample code JDBC Tutorial jdbc type 1 driver jdbc type 2 driver jdbc type 3 driver jdbc type 4 driver Jdeveloper JDK JDK8 JEE Tutorial jframe jframe creation jframe position jframe positioning JIRA JMeter JMS JMX join() joining threads JPA JQuery JS JSF JSF Tutorial JSONP JSP jsp and java beans jsp and servlets jsp and xml jsp api jsp code jsp compilation jsp conversion jsp directives jsp error page jsp error page directive jsp implicit objects jsp interview jsp interview questions jsp introduction jsp intvw questions jsp life jsp life cycle jsp life-cycle jsp lifecycle jsp page directive jsp questions jsp sample jsp scripting jsp scriptlets jsp servlets jsp summary jsp synopsis jsp tag libraries jsp tag library jsp taglib jsp tags jsp technology jsp to servlet jsp to servlet conversion jsp translation jsp usage jsp usebean jsp xml tags jsp xml tags usage jsp-servlet jsp:getProperty jsp:setProperty jsp:usebean jsps JSTL JUnit testing keyword synchronized keyword volatile Keywords Lambda Expressions Learning libraries life cycle life cycle of a jsp life cycle of a servlet life cycle of a thread life cycle of jsp life cycle of threads lifecycle of a thread linked list linkedhashmap linkedhashset linkedlist linux List listeners lists Literals locale lock manager pattern lock scope locking objects using threads log Logging logging errors logical and logical operators logical or loops loosely coupled making an arraylist making threads sleep making threads sleep for time MapReduce maps maps usage Maven Maven Tutorial max priority member access method arguments method local inner class method overloading method overriding method return types methods creating classes min priority Miscellaneous mobile mock exam model view controller model view controller design pattern model view controller pattern Multi Threading Multi-threading multiple threads multiplication multithreading multithreading in java multithreading interview questions multithreading questions mvc mvc design pattern mvc pattern MyEclipse mysql nested java lock nested java locks nested java thread locks nested locks nested thread locks NetBeans Networking new news nio NonAccess Modifiers norm priority normal inner class Normalization not equal to Notepad notify notifyall number format numberformat numbers object comparison object notify object orientation object oriented object oriented programming Object Oriented Programming in java objects interview questions ocmjd certification ocmjd certification eligibility OO OO Java oops OpenCSV OpenCV opening jsp tags OpenJDK OpenJFX Operators or Oracle Oracle ADF Mobile Oracle Certified Exams oracle certified master java developer oracle database ORM other topics out overloading overloading constructors overloading in java overriding page page directive page scope parsing passing variables passing variables to methods performance Platform Playing with Numbers points to remember polymorphism positioning a frame post practice exam Primitive Casting primitive variables printwriter priority queue priority queues priorityqueue priorityqueues private processing form values Products programming Projects protected public put questions questions on garbage collection questions on java strings queue quick recap quick review race conditions read objects from stream reading http request header RealTime_Tips redirecting to another servlet redirection reference reference variable casting reference variables Refreshing Java regex Regular Expressions regular inner class relational operators reminder request request dispatcher request forwarding request header request object. httpservletrequest request scope requestdispatcher response RESTClient RESTful retrieving values from session return error codes return types returning values runnable runnable interface running running java programs RUP sample jsp sample questions sample questions scwcd sample servlet scanner Scene Builder scjd certification scjd certification eligibility requirements scjp SCJP Certification scjp exam scjp exam questions scjp exam sample questions scjp questions scjp test scjp test questions scope scope of java locks scope of java thread locks scope of locks scripting in jsp scriptlet tags scriptlets scriptlets in jsp pages scwcd scwcd certification scwcd certification practice exam scwcd exam scwcd exam questions scwcd jsp summary scwcd mock exam scwcd mock exam answers scwcd practice exam scwcd practice test scwcd questions scwcd test SDLC searching searching arrays searching collections searching in java searching treemap searching treesets security self assement self assement scwcd self assessment scjp self test self test scjp self test scwcd send error method senderror method sending error code to browser serialization serialization in java serialization interview questions Serialization on Swing serialization questions service service method servlet servlet and forms servlet and jsp servlet api servlet attributes servlet code servlet container servlet context servlet error handling servlet exception handling servlet handling http request servlet initialization servlet initialization parameters servlet interview servlet interview questions servlet interview questions with answers servlet intvw questions servlet life cycle servlet lifecycle servlet questions servlet questions with answers servlet request servlet request dispatcher servlet request type servlet skeleton servletcontext servletcontextevent servletrequest Servlets servlets and jsps servlets api servlets details servlets request handling session session clean up session event listeners session facade pattern session interview questions session invalidation session listeners session management session questions session scope session timeout session tracking through url rewriting set collections set status method setattribute sets setstatus method setting bean property setting request type short circuit operators Singleton sleep sleeping threads soapUI Software Installation sorting sorting arraylist sorting arrays sorting collections special collections special inner classes split spring spring and hibernate interview questions spring batch Spring Core Spring Framework Spring Integration spring interview questions Spring JDBC Spring MVC Spring security Spring tutorial SQL SQL and database tutorial examples SQL Tutorial SSL stack stacks stacks and heaps static static class static declaration static imports static inner static inner class static method Static variable stopped stopping a thread stopping thread stopping threads Stored Procedure storing values in session Streams strictfp StrictMath string string buffer string builder string class string formatting String Handling string interview questions string manupulation string questions string tokenizer stringbuffer stringbuffer questions stringbuilder Strings strings in java struts Struts 1 Struts 1.2 Struts 2 struts framework interview questions struts interview questions struts interview questions with answers struts mvc interview questions struts questions Struts2 StrutsBooks submitting request subtraction Sun Certification sun certified java developer Sun Certified Java Programmer swing swing action performed swing and colors Swing Components swing event handling swing event listeners swing events Swing Hacks swing images Swing Look And Feels swings swings frame switch block switch case block switch case statement Sybase Sybase and SQL Server synchronization synchronized code synchronized keyword synchronized method System Properties tag lib tag library tag-lib taglibs tags TDD Technical Blogging ternary operator Test Driven Development test scjp Testing the context the session the volatile keyword thread thread class thread deadlocks thread interaction thread interruption thread life cycle thread lifecycle thread lock scope thread locks thread notify thread priorities thread race conditions race conditions in threads thread sleep thread states thread stoppage thread stopping thread synchronization thread syncing thread yield Threads threads in java threads interview questions threads life cycle threads questions tibco tightly coupled tips tips and tricks tips.FXML tokenizing Tomcat Tools toString transitions treemap treeset tricks Tricks Bag try catch try catch finally. finally block Tutorial type casting in java ui programming with java swings UML unboxing unit testing unix url rewriting use bean usebean using a arraylist using collections using colors using colours using command line arguments using different fonts using expressions using font using fonts using fonts in swings using hashmap using http session using httpsession using iterator using java beans in jsp using javabean in jsp using javabeans in jsp using javac using lists using maps using request dispatcher using scriptlets using session persistense using sets using special fonts using system properties using the jsp use bean using treeset using use bean Using Variables using volatile Using Wrappers using xml in jsp Util pack value object value object design pattern value object pattern var-args varargs Variable Arguments Variables vector vector questions vectors visibility vo pattern volatile volatile keyword volatile variables wait method waiting web app exception handling web app interview web application deployment web application exceptions web application scope web application security web component developer web component developer certification web context web context interfaces web context listeners web interview questions web security web server web servers Web services web.xml web.xml deployment webapp log weblogic website hacking website security what are threads what is a java thread what is a thread what is thread while loop windows windows 8 wrapper classes wrappers write objects to stream WSAD xml xml and jsp xml tags xslt yield()