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See:
Description
Class Summary | |
---|---|
BaseItem | An optional base class for server objects. |
BaseProxy | A standard abstract base class for proxy objects. |
CodebaseServer | The standard mechanism to send proxies, and other complex objects to remote VMs. |
ItemServer | These routines are used for server object construction. |
MonitorItem | This class is used to instrument an object for invocation logging purposes. |
Multicast | This class can listen for UDP multicasts over the network, as well as to send out UDP announcements. |
ProxyLoader | This class is used to avoid having to load proxies into the VM runtime of the proxy server. |
ZippedProxy | This class is used to transfer its internal proxy object as a zipped marshalled object (zedmob). |
A set of common utilities used by either proxy, or server items. As a general rule, do not compile all of the utility classes blindly; rather jar any classes resulting from the compilation of the proxy or server applications. As a rule, a proxy hosting VM is not required to have these classes in its classpath; therefore, the ones used from this package by a proxy application must be included in the proxy's codebase jar file.
Fundamentally, there are two entities; clients and servers. A server is a
Virtual Machine which, at a minimum, exports one item, meaning a remotely
invokable object implementing the Invoke
interface. A server can also provide proxies; i.e. mobile item interfaces, to
the server's local item objects (exported or not), which run inside the
client's runtime. A client is a VM that makes use of a server's items and
proxies, but need not export any of its own. The architecture readily supports
the possibility of hybrid client/server VMs. Each VM can export as many items
as it wants.
Items can transparently connect to other items across, logical, virtual or physical separation. This package seeks to establish the following roles between items:
An item is a control element of a system, it performs three major tasks:
When the items are remote; the overall network structure looks something like this:
-------------- -------------- | Server VM | | Client VM | | ---------- | TCP | ---------- | | | Item | | links | | Proxy | | | |----------| | | |----------| | | | http | |<------| | codebase | | | | callback | |<------| | notify | | | | notify | |------>| | callback | | | ---------- | | ---------- | -------------- --------------Note: Each outgoing TCP link consumes a corresponding anonymous return link, so the following port consumption realities for a server VM must be considered:
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