An ORD is an “Object Resolution Descriptor”. The ORD is the Niagara universal identification system and is used throughout the Niagara framework. The ORD unifies and standardizes access to all information. It is designed to combine different naming systems into a single string and has the advantage of being parsable by a host of public APIs.
An ORD is comprised of one or more queries where each query has a scheme that identifies how to parse and resolve to an object. ORDs may be displayed visually, as with the Open Ord locator or they may be entered in a text field, as shown in the Open ORD dialog box (see Figure 19).
ORDs can be relative or absolute. An absolute ORD usually takes the general format of “host│session│space”, as illustrated in Figure 20.
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host
The host query identifies a machine – usually by an IP address such as “ip:hostname”. For example “fox:” indicates a fox session to the host.
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session
The session is used to identify a protocol being used to communicate with the host.
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space
The space query is used to identify a particular type of object. Common spaces are “module:”, “file:”, “station:”, “view:”, “spy:”, or “history:”.
The local VM is a special case identified by “local:” which always resolves to BLocalHost.INSTANCE. The local host is both a host and a session (since no communication protocols are required for access).
Both a slot path and a handle scheme can name components within a ComponentSpace. So the ORD for a component usually involves both a space query and a path/handle.
Example 1. Examples of ORDs:
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ip:somehost│fox:│station:│slot:/MyService
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ip:somehost│fox:│station:│h:/42
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ip:somehost│fox:│file:/C:/dir/file.txt
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local:│file:!lib/log.properties
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local:│module://icons/x16/cloud.png
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local:│spy:/
In Niagara you may view the complete list of installed ORD schemes at “spy:/sysManagers/registryManager/ordSchemes” (“local:│fox:│spy:/sysManagers/registryManager/ordSchemes”).