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| <document> |
| <properties> |
| <title>FAQ</title> |
| </properties> |
| <body> |
| <section name="Apache Synapse FAQs"> |
| <p> |
| Welcome to Apache Synapse FAQs. |
| </p> |
| </section> |
| <section name="General(GeneralApache Synapse questions - Non technical)"> |
| <ol> |
| <li> |
| What is Apache Synapse? |
| <ul> |
| <li> |
| Apache Synapse is a lightweight and high-performance Enterprise Service |
| Bus (ESB). |
| </li> |
| </ul> |
| </li> |
| <p/> |
| |
| <li> |
| What makes Apache Synapse unique? |
| <ul> |
| <li> |
| Apache Synapse is fast and able to handle thousands of concurrent |
| connections |
| with constant memory usage. It comes with a rich set of mediators to |
| support almost any integration scenario out of the box. It is also |
| easily |
| extensible and highly customizable. |
| </li> |
| </ul> |
| </li> |
| <p/> |
| <li> |
| What is the license? |
| <ul> |
| <li> |
| Apache Synapse comes with Apache 2.0 licence. |
| </li> |
| </ul> |
| </li> |
| <p/> |
| </ol> |
| </section> |
| |
| <section name="Mediation(Questions related to sequences, endpoints, proxies etc)"> |
| <ol> |
| <li> |
| What is a proxy service? |
| <ul> |
| <li> |
| A proxy service is a virtual service hosted on the ESB. It can accept |
| requests from service clients, just like a real Web Service. A proxy |
| service can process requests and forward them to an actual Web Service |
| (back end service) to be further processed. The responses coming back |
| from |
| the back end service can be routed back to the original client. Proxy |
| services are mostly used to expose an existing service over a different |
| transport, format or QoS configuration. |
| </li> |
| </ul> |
| </li> |
| <p/> |
| |
| <li> |
| What is a mediator? |
| <ul> |
| <li> |
| A mediator is the basic message processing unit in the ESB. A mediator |
| can take a message, carry out some predefined actions on it and output |
| the modified message. Apache Synapse ships with a range of mediators capable |
| of carrying out various tasks on input messages. |
| </li> |
| </ul> |
| </li> |
| <p/> |
| <li> |
| What is a sequence? |
| <ul> |
| <li> |
| A sequence is an ordered list of mediators (a mediator chain). When a |
| sequence is given a message, it will go through all the mediators in the |
| sequence. A sequence can also handover messages to other sequences. |
| </li> |
| </ul> |
| </li> |
| <p/> |
| <li> |
| What is an Endpoint? |
| <ul> |
| <li> |
| A logical representation of an actual endpoint or a group of endpoints |
| (i.e. Load Balancing and Fail Over). |
| </li> |
| </ul> |
| </li> |
| <p/> |
| <li> |
| What are Local Entries? |
| <ul> |
| <li> |
| Local entries can be used to hold various configuration elements |
| required by sequences and proxy services. Usually they are used to hold |
| WSDLs, XSDs, XSLT files etc. A local entry can contain XML content as |
| well |
| as plain text content. A local entry can be configured to load content |
| from a remote file too. |
| </li> |
| </ul> |
| </li> |
| <p/> |
| |
| <li> |
| What is a Message Mediation? |
| <ul> |
| <li> |
| Managing and transforming the messages flowing between the client and a |
| service in an enterprise. |
| </li> |
| </ul> |
| </li> |
| <p/> |
| |
| <li> |
| What is Message Mediation? |
| <ul> |
| <li> |
| Mediating messages coming into a specific service by specifying the |
| target URI as a Synapse mediation service. |
| </li> |
| </ul> |
| </li> |
| <p/> |
| <li> |
| What is Service Mediation? |
| <ul> |
| <li> |
| Mediating messages coming into a specific service by specifying the |
| target URI as a Synapse mediation service. |
| </li> |
| </ul> |
| </li> |
| <p/> |
| <li> |
| What is a Message Store? |
| <ul> |
| <li> |
| Message Store is the storage for ESB messages. It can be an in-memory |
| store |
| or can be JMS store with an external Message Broker. You can always plug |
| your |
| own message store implementations as well. |
| </li> |
| </ul> |
| </li> |
| <p/> |
| <li> |
| What is a Message Processor? |
| <ul> |
| <li> |
| Message processor can be used to implement different messaging and |
| integration patters along with Message stores. Message processors will |
| consume |
| the messages in message stores and do the processing of them. |
| </li> |
| </ul> |
| </li> |
| <p/> |
| <li> |
| What is a Template? |
| <ul> |
| <li> |
| ESB Templates try to minimize this redundancy by creating prototypes |
| that |
| users can re-use and utilize as and when needed. This is very much |
| analogous |
| to classes and instances of classes where-as, a template is a class that |
| can be used to wield instance objects such as templates and endpoints. |
| </li> |
| </ul> |
| </li> |
| <p/> |
| <li> |
| What is the REST Api? |
| <ul> |
| <li> |
| REST Api can be used to mediate HTTP POST, GET, PUT and DELETE request |
| through Synapse and to integrate various RESTful services. |
| </li> |
| </ul> |
| </li> |
| <p/> |
| <li> |
| Can Endpoint perform error handling? |
| <ul> |
| <li> |
| Yes. Endpoints can do error handling. User can configure the behavior |
| of an endpoints when it faced to a erroneous situation. |
| </li> |
| </ul> |
| </li> |
| <p/> |
| </ol> |
| </section> |
| <section name="Transports(Transport related questions)"> |
| <ol> |
| <li> |
| What are the transports supported by the Apache Synapse? |
| <ul> |
| <li> |
| HTTP, HTTPS, VFS based file transport, FIX, Hessian, HL7,UDP, JMS, Mail, |
| TCP, XMPP |
| </li> |
| </ul> |
| </li> |
| <p/> |
| |
| <li> |
| Do I need an external JMS broker for the JMS transport? |
| <ul> |
| <li> |
| Yes, Apache Synapse requires an external JMS broker like Apache ActiveMQ |
| </li> |
| </ul> |
| </li> |
| <p/> |
| <li> |
| Does Apache Synapse support two way JMS scenario (request/response) ? |
| <ul> |
| <li> |
| Yes, you can refer sample 264 which demonstrates exactly the JMS |
| request/response scenario. |
| </li> |
| </ul> |
| </li> |
| <p/> |
| <li> |
| What is the NHTTP transport? |
| <ul> |
| <li> |
| This is the default HTTP transport used by Apache Synapse. NHTTP stands for |
| non-blocking HTTP. NHTTP transport uses the Java Non-blocking I/O API. |
| This allows the NHTTP transport to scale into handling hundreds of connections |
| without blocking the threads. The server worker threads used by the NHTTP |
| transport do not get blocked on I/O until the Synapse receives responses |
| for the already forwarded requests. Therefore Apache Synapse can accept |
| more concurrent connections and requests than most HTTP server products. |
| </li> |
| </ul> |
| </li> |
| <p/> |
| <li> |
| What is the underlying HTTP library used by the NHTTP transport? |
| <ul> |
| <li> |
| NHTTP transport uses the Apache Http Core NIO library underneath. This |
| library provides low level I/O handling and HTTP level detail handling. |
| </li> |
| </ul> |
| </li> |
| <p/> |
| </ol> |
| </section> |
| |
| </body> |
| </document> |
