Glossary
Component
Components in the Carbon platform add functionality to all WSO2 Carbon-based products. For example, the statistics component enables users to monitor system and service level statistics. A component in the Carbon platform is made up of one or more OSGi bundles, which is the modularization unit in OSGi similar to a JAR file in Java. For example, the statistics component contains two bundles: one is the back-end bundle that collects, summarizes, and stores statistics, and the other is the front-end bundle, which presents the data to the user through a user-friendly interface. This component-based architecture of the WSO2 Carbon platform gives developers flexibility to build efficient and lean products that best suit their unique business needs simply by adding and removing components.
Default Endpoint
A default endpoint is an endpoint defined for adding Quality of Service (QoS) and other configurations to the endpoint, which is resolved from the To
address of the message context.
Endpoint
An endpoint is a specific destination for a message. It may be specified as an Address endpoint, WSDL endpoint, a Failover group, a Loadbalance group, and more. Endpoints can be added, edited, and deleted.
Embedded Registry Instance
The Embedded Registry Instance makes use of the embedded AS database. This is a H2 database and the data files are stored by default in the directory named AS_HOME/repository/database
. If you run the AS in the embedded registry mode, you should be careful not to alter manually any files stored in this directory as that might lead to database corruption or data loss.
Event Sources
An Event Source is used to define the event source and the subscription manager configuration used in the eventing implementation of WSO2 AS. An Event Source provides a service URL that can be used to the send subscriptions and events (events that are not required to go through a mediation flow).
J2EE
Abbreviation for "Java 2 Platform, Enterprise Edition". Now known as "Java Platform, Enterprise Edition" or "Java EE"
Keystore
The keystore used to encrypt administrator passwords and other confidential information in Carbon is configured in AS_HOME/repository/conf/carbon.xml
file. This keystore configuration can be found under the <security> element of the carbon.xml
file.
Mediator
A mediator is a full powered processing unit. It is a component that performs some mediation action on a message during the process flow. Thus, a mediator gets full access to a message at the point where it is defined to gain control and could inspect the message, modify it or take an external action depending on some attributes or values of the current message.
Port offset
The port offset feature allows you to run multiple WSO2 products, multiple instances of a WSO2 product, or multiple WSO2 product clusters on the same server or virtual machine (VM). The port offset defines the number by which all ports defined in the runtime such as the HTTP/S ports will be offset. For example, if the HTTP port is defined as 9763 and the portOffset is 1, the effective HTTP port will be 9764. Therefore, for each additional WSO2 product, instance, or cluster you add to a server, set the port offset to a unique value (the default is 0).
Port offset can be passed to the server during startup as follows:
./wso2server.sh -DportOffset=3
Alternatively, you can set it in the Ports section of <PRODUCT_HOME>/repository/conf/carbon.xml file as follows:
<Offset>3</Offset>
Proxy Services
A Proxy Service is a virtual service hosted in the AS runtime. The proxy service mediates any accepted requests and forwards them to a specified endpoint, most of the time to an actual Web Service. The responses coming back from the target endpoint are mediated back to the client which sent the original service request. Proxy services often make references to sequences, endpoints and local entries. A proxy service can enforce various QoS requirements on a request and can be exposed over a user specified transport. Therefore they are often used to expose existing Web Services over a different transport or a QoS configuration. For example, a proxy service can be used to expose an HTTP service over JMS or it can be used to expose an unsecured service in a secured manner using WS-Security standards.
Unlike sequences and endpoints, which can be stored and loaded from the registry, proxy services cannot be loaded from the registry. However, a proxy service can make references to sequences and endpoints stored in the registry.
Sequence
A Sequence element is used to define a Sequence of mediators that can be invoked later as a Sequence. If the configuration defines a Sequence named "main", then it is considered as the main mediation Sequence of the AS. If such a Sequence is not defined locally and a registry has been specified, the registry is looked up for a key named "main" to find the main mediator Sequence. If the user does not define a main or fault Sequence, AS will create default Sequences.
Servlet
A servlet is a small Java program that runs within a Web server. Servlets receive and respond to requests from Web clients, usually across HTTP, the HyperText Transfer Protocol.
Servlet container
The Servlet Container (such as Apache Tomcat) is an application that monitors a port on a given IP address. Servlets generate responses to HTTP requests. To do so, the container loads your servlet (if it is not in memory already) and calls the methods defined in the interface. This is the foundation of servlet and JSP architecture.
SOAP
An XML-based, extensible message envelope format, with "bindings" to underlying protocols. The primary protocols are HTTP and HTTPS, although bindings for others, including SMTP and XMPP, have been written.
synapse-config
Directory
The synapse-config
Directory houses the Mediation Configuration (Synapse Configuration) of WSO2 AS and contains several files and subdirectories. Usually the following set of child directories is available in the synapse-config Directory: endpoints, event-sources, local-entries, priority-executors, proxy-services, sequences, tasks.
Tasks
A Task is a custom Java class that implements the org.apache.synapse.startup
. Task interface that defines a single public void execute()
method. Such a Task can be scheduled and managed via the AS. The scheduling information for a Task can be specified in the cron
format or a simple
format by the user. A Task may also be specified as a one-time Task where required and can be used to trigger a callout or inject a message into the AS.
WS-Addressing
WS-Addressing was originally designed as the way to convey connection state or context in SOAP messages, emulating the contextualization mechanism provided by HTTP headers in conjunction with stored cookies. This makes it possible to contextualize message exchanges in a similar way, independently of the transport used.
WSDL
An XML format allows service interfaces to be described along with the details of their bindings to specific protocols. It is typically used to generate server and client code and for configuration.
WSDL Endpoint
WSDL Endpoint is an endpoint definition based on a specified WSDL document. The WSDL document can be specified either as a URI or as an inlined definition within the configuration.
WSO2 AS Management Console
WSO2 AS Management Console is a Web based control panel powered by JSP and AJAX which enables system administrators to interact with a running AS instance without touching any underlying configuration files. The Management Console allows the users to command and control proxy services, sequences, transports, local entries, registry, modules, endpoints and much more.