ECF Generic Client
ECF Generic Server
ECF Bittorrent Filetransfer
Container Types Available at ECF Github site
Container Factory Name
Container Instance Disposal
When no longer required the IContainer.dispose() method should be called to release any resources associated with the container instance upon its construction or used during its lifecycle (e.g. network resources, etc).
Connection/Disconnection
The IContainer interface exposes two key methods: connect(ID targetID, IConnectContext connectContext) and disconnect(). As is obvious, these two methods allow container implementations to initiate communication with remote services, either server-based or group-based communications.
Notice the first parameter to the connect method. targetID. TargetID is of type ID. The targetID parameter identifies the target server or group for the connect operation. It is of type ID so that the to allow the target communications service to be of many kinds. e.g. client-server or peer-to-peer. For example, for http communication the targetID would consist of the URL specifying a particular file at a particular path on a particular server. e.g: http://www.eclipse.org/ecf. For some other communications protocol the ID provided would be different. e.g: sip:someone@example.com;transport=tcp. All such targets for connect may be represented via an instance of the ID interface.
Example Code: Container Creation and Connection
Here's an example code snippet that shows the creation and connection of an ECF container:// make container instance IContainer cont = getContainerFactory().createContainer("ecf.generic.client"); // make targetID ID targetID = IDFactory.getDefault().createID(cont.getConnectNamespace(),"ecftcp://foo.com:3282/server"); // then connect to targetID with null authentication data cont.connect(targetID,null);
Namespaces and ID Construction
The org.eclipse.ecf core plugin defines a namespace extension point, so that ECF provider plugins can provide their own Namespace implementations. For example, here is the namespace extension definition for the org.eclipse.ecf.provider.xmpp plugin:
This assigns the name "ecf.xmpp" to the class org.eclipse.ecf.provider.xmpp.identity.XMPPNamespace. Notice that this class must be a subclass of org.eclipse.ecf.core.identity.Namespace. The XMPPNamespace class provides the XMPP namespace implementation and as described above implements the XMPP namespace restrictions. It is also responsible for constructing new ID instances via the ECF IDFactory. For example, to construct an instance of and XMPP ID, a client could use the following code:
ID newID = IDFactory.getDefault().createID("ecf.xmpp","slewis@foo.com");
- The name "ecf.xmpp" is used to lookup it's associated Namespace class (in this case XMPPNamespace). This lookup is done via the Eclipse extension registry.
- The XMPPNamespace.createInstance method is called to manufacture an ID that is in the XMPPNamespace from the string "slewis@foo.com"
- The new ID is returned to the caller
Container Extensibility through Adapters
To support run-time extensibility, the IContainer interface inherits from org.eclipse.core.runtime.IAdaptable. This interface exposes a single method: the 'getAdapter(Class intf)' method. In the case of IContainer instances, this allows client applications to query the IContainer instance at runtime about it's exposed capabilities, and get access to those capabilities if they are available. So, for example, perhaps we're interested in creating an instant messaging application and wish to use the capabilities exposed by the IPresenceContainer interface. To do this, we simply query the IContainer instance at runtime to see if it provides access to IPresenceContainer capabilities:
IPresenceContainer pc = (IPresenceContainer) cont.getAdapter(IPresenceContainer.class); if (pc != null) < // The container DOES expose IPresenceContainer capabilities, so we can use them! >else < // The container does not expose IPresenceContainer capabilities. we're out of luck >
Among other positive characteristics, this adapter mechanism provides a consistent-yet-simple way for a wide variety of container types to be defined and used without the need to update the ECF IContainer abstractions. See the documentation for the IContainer.getAdapter() method. See also a terrific article on EclipseZone about usage of IAdaptable for runtime extensibility
Identity
In ECF, identity of local or remote entities such as users, remote services, and groups are all represented via the ID interface. This interface provides the basic contract for addressing uniquely identified entities. ID instances belong to a given Namespace Namespaces define the range of allowable values of the ID instances belonging to that Namespace. So, for example, the Namespace of XMPP (Jabber) user identities is defined by XMPP RFC3920 as having the following structure
jid = [ node "@" ] domain [ "/" resource ] domain = fqdn / address-literal fqdn = (sub-domain 1*("." sub-domain)) sub-domain = (internationalized domain label) address-literal = IPv4address / IPv6address example = slewis@foo.com/ecf
The ECF XMPP provider implementation restricts jids to this syntax by providing a Namespace subclass responsible for constructing ID instances that follow the rules defined by the protocol specification. Other communications protocols and their associated service identities have their own Namespaces (e.g. ftp, http, sip, irc, etc, etc), each with it's own requirements for addressing and identity. The ID contract is not bound to any specific protocol, and makes it possible to create client applications that are insensitive to the addressing differences between protocols while still guaranteeing basic uniqueness requirements within a given namespace.
Example: Container creation, ID creation, container adapter, and connection
// Create the new container IContainer client = ContainerFactory .getDefault().createContainer(containerType); // Create the targetID ID targetID = IDFactory.getDefault().createID(client.getConnectNamespace(), uri); // Check for IPresenceContainer. if it is, setup presence UI, if not setup shared object container IPresenceContainer pc = (IPresenceContainer) client .getAdapter(IPresenceContainer.class); if (pc != null) < // Setup presence UI presenceContainerUI = new PresenceContainerUI(pc); presenceContainerUI.setup(client, targetID, username); >else throw new NullPointerException("IPresenceContainer interface not exposed by client with type "+containerType); // connect client.connect(targetID, getJoinContext(username, connectData));
