IberAgents Reference

In order to have a complete picture of the capabilities provided by IberAgents, this section describes all components in IberAgents.

Introduction

This document describes every component currently shipped with IberAgents, for reference purposes. Developer are encouraged to browse the list to see if any of them fulfills their needs, and to discover new functionalities.

It complements the documentation for features and status of the framework.

Default Components

Default components are hard-coded to start with the platform. They provide essential capabilities to the framework, and are shown here in startup order.

Package	Component	Type	Description
com.iberagents.registry.local	LocalPlatform	Restartable Configurable	The first component to start, it starts the remaining components. When the default ones are running, reads the configuration file and starts the rest.
com.iberagents.registry	LocalFinder	Restartable	Registers components on the local node, and to the global registry. Locates local comoponents.
com.iberagents.registry.remote	GlobalRegistry	Service	Registers and locates components on all nodes. It is started by the local finder only when this is the registry node.
com.iberagents.run	Activator	Component	Starts and stops restartable components and agents.
com.iberagents.bean	Invoker	Component	Used to invoke methods on components by reflection, when the method name comes from a web request or a soap message.
com.iberagents.bean.xpath	Modifier	Component	Modifies bean objects contents according to XPath statements, used in bean edition.
com.iberagents.bean.marshal	MarshalerFactory	Restartable	Decides which Marshaler is responsible of marshaling (serialization) for a given object. Used internally by the serializer. Developers can add custom marshalers for bean edition.
com.iberagents.bean.serial	Serializer	Component	Converts bean objects into xml documents, and back.
com.iberagents.bean	BeanArchiver	Component	Stores the contents of a bean into a single xml file. Used in persistence and configuration.
com.iberagents.bean	Descriptor	Component	Low level manipulation of bean objects. Finds bean properties, instantiates objects.
com.iberagents.task	AgentManager	Restartable	Responsible to start and locate agents, also keeps them running in the event of an unexpected error.
com.iberagents.web.process	WebFinder	Component	Finds web components looking at the request.
com.iberagents.config	Configurator	Restartable	Reads configuration files and sends the resulting objects to Configurable components.

Other Components

The remaining components are optional; the administrator can add or remove them in the global configuration as necessary. They are shown below in alphabetical order (by package).

Package	Component	Type	Description
com.iberagents.bean.edit	BeanEditor	Component	Enables the edition of bean object values from a web interface. Usually called from other components so that it manipulates internally bean values.
com.iberagents.bind	Binder	Restartable Configurable	Starts and stops the internal servlet engine, and also binds to external nodes for soap communication. Is responsible of creating proxies to external services.
com.iberagents.bind.send	Deliverer	Agent Configurable	Receives messages that must be sent to another node, and queues them for delivery from its own thread. Can also be configured to send messages directly.
com.iberagents.bind.receive	LocalReceiver	Component	External messages to the local node go to this component, which is responsible for locating the target service and calling the right method.
com.iberagents.config	Editor	AdminComponent	Lets an administrator change configuration values for IberAgents components via web.
com.iberagents.deploy	Deployer	Restartable Agent Configurable	Loads external applications, including classes, components, XSL files and a configuraton file. Checks the extension directory at regular intervals, and reloads any application that has changed.
com.iberagents.harvest	WebHarvester	Restartable Configurable Service	Collects the contents of external web pages. Uses Jakarta HttpClient to open URLs.
com.iberagents.list.edit	ListEditor	Component	Manages lists presented as web pages. Lists are a construct used when several items (each in turn a bean object) have to be presented as a single web page, with the usual pagination capabilities.
com.iberagents.log	Logger	Configurable	Receives logging events and shows them and / or stores them to disk. The default implementation just shows errors on console; a more refined one uses log4j as the underlying logging library.
com.iberagents.mail	Emailer	Service Configurable	Very simple interface for sending email messages using the configured SMTP host.
com.iberagents.persistence.binary	BinaryPersistence	Restartable	Part of the persistence layer, stores binary objects (i.e. arrays of bytes), usually as regular files.
com.iberagents.persistence.local	LocalPersistence	Restartable Agent Configurable	Caches persistent objects so they are not stored or read every time they are requested to do so, but at regular intervals.
com.iberagents.persistence	Persistence	Restartable	User interface for the persistence layer. Can store, read and delete persistent objects; and perform complex database-like queries.
com.iberagents.persistence.pool	ConnectionPool	Restartable Configurable	Manages a number of connections to the underlying database, and checks they are within the configured bounds.
com.iberagents.registry.remote	RemoteFinder	Restartable Configurable	Locates services on remote nodes; it is also responsible for registering and unregistering on the node that contains the global registry.
com.iberagents.run	Monitor	AdminComponent	Lets an administrator start, stop, suspend or resume running agents via web. Platform restart is also supported.
com.iberagents.security	CertificateManager	Restartable Configurable	Loads digital certificates from storage and makes them available to the servlet engine. An essential part of security.
com.iberagents.soap.generate	SoapGenerator	Component	Generates the correct xml document for a given SOAP message: objects are serialized, method calls are converted to bindings.
com.iberagents.soap.send	Sender	Component	Sends SOAP messages to remote nodes. Uses Jakarta HttpClient to make POST requests.
com.iberagents.task	AgentFinder	Service	Returns the descriptions of agents running on a node.
com.iberagents.user	LifeCycleManager	WebComponent	Creates user components when a new user connects, and redirects all queries to the correct user component using a browser cookie.
com.iberagents.user.admin	UserManager	AdminComponent	Lets an administrator create, edit and delete users (in development).
com.iberagents.user.admin	SessionAdmin	AdminComponent	A debug component that shows all parameters in the current session.
com.iberagents.user.login	Challenger	Restartable	Provides security services such as challenge generation and MD5 digest computation; the included implementation uses Java JSSE.
com.iberagents.user.login	LoginRegistry	Restartable Agent	Keeps login information for user components, and expires them after the configured time.
com.iberagents.web.process	RequestProcessor	Component	The interface between the internal servlet engine and the platform component discovery. When a web request (GET or POST) comes in, it locates the target component and calls the appropriate method.
com.iberagents.web.xsl	XSLTransformer	Restartable	Performs XSL transformations, using Xalan-Java. Caches XSL transformers, and reloads the .xsl files when they change.

Configuration Components

Configuration components contain values that must be accessible to several components, as opposed to Configuration objects which are tied to a specific component. Its values can be modified at runtime by an administrator.

Package	Component	Description
com.iberagents.persistence.file	FilePersistenceConfiguration	Contains the location of files when file persistence is used.
com.iberagents.persistence.statement	SQLFactory	Contains pieces of SQL statements, that are composed to form statements sent to the underlying database. This is the component to change when customizing IberAgents for a particular database.
com.iberagents.soap	MulticastConfiguration	Controls time to wait for responses in multicast requests.
com.iberagents.soap.map	MappingConfiguration	Used by the soap generator to use the correct namespace mappings, and also by individual soap marshalers.
com.iberagents.task	LifeCycleConfiguration	Sets expiration time for user components, and how often the login registry must check for expired components. Also used by the binder to set cookie expiration time.
com.iberagents.user.admin	AdminPreferences	Contains the username and password for administrator access to admin components.

Other Important Objects

There are a few objects, not defined as components, which are also important for operation.

Package	Object	Description
com.iberagents.soap	SoapServlet	Servlet that receives and responds to SOAP messages and WSDL requests; uses the local receiver to locate the receiving component.
com.iberagents.web	ReceivingServlet	Servlet that receives web requests and passes them along to the request processor.