[A brief version of this page can be found here.]

Here are some forms that exercise the client-side services of an ADL middleware server. The forms access the server whose HTTP interface has the following base URL (can be changed dynamically; should end with a '/'):

And here are the forms, one per middleware service...

• The configuration servlet/service returns middleware configuration parameters as an XML document.
• The status servlet/service returns an HTML document describing the status of the middleware.
• The collection servlet/service returns the collection-level metadata for a collection as an XML document.
• The query servlet/service asynchronously queries one or more collections for items that match one or more constraints. The general structure of the ADL query language is defined by ADL-query.dtd and the standard ADL search buckets that constraints may be placed against are described under client interfaces. Ordinarily the return is an integer that identifies both the running query and the corresponding result set, but if "intercept query/result set ID" is checked below, the integer is intercepted and inserted into the next two forms on this page.

  <?xml version="1.0"?> <ADL-query> <collections> <collection>collection</collection> </collections> <textual-constraint> <bucket>adl:subject-related-text</bucket> <operator>contains-any-words</operator> <text>goleta</text> </textual-constraint> </ADL-query> intercept query/result set ID

• The cancel servlet/service cancels a currently-running query.
• The results servlet/service accesses a result set. The status and wait operations both return the status of the result set as an XML document; the difference is that wait blocks until the result set is complete. The get operation returns the result at index index, the multiget operation, the results at indices [from, to); in both cases, which of the three standard ADL metadata views to return per result is specified using a comma-separated list. The get-query operation returns the query that created the result set as an XML document.

  	delete get multiget status wait get-query

• The identifiers servlet/service returns the identifiers of all items in a collection.
• The metadata servlet/service returns a view of the metadata for a collection item. The view may be one of the three standard ADL metadata views (adl:bucket, adl:browse, or adl:access) or any other view supported by the item. The fictitious view adl:view-list returns a list of the supported views.
• The reference servlet/service creates a collection that is a proxy to a remote collection. The remote collection is specified by a remote middleware server (which is identified by an RMI or, someday, HTTP base URL) and a remote collection name. If the base URL includes a service prefix, it should end with a '/'; otherwise, the prefix is assumed to be "/edu/ucsb/adl/middleware/rmi/", which it is by default. The collection is referred to locally as localname if supplied.
• The unreference servlet/service removes a proxy collection.
• The unload servlet/service unloads the drivers for a collection. Any subsequent reference to the collection will cause the collection's configuration files to be reloaded.

The following aren't really middleware services, but they're useful for testing and administration purposes.

• The collection_availability servlet disables (i.e., takes offline) or enables a collection.
  enable disable
• The cache_control servlet empties the metadata cache for a collection and metadata view, or starts or stops a thread to preload the metadata cache. If "*" is specified for the view, all of the collection's caches are operated on.
  empty preload stop
• The rmi_control servlet enables (rebind) or disables (unbind) the middleware's RMI interface.
  rebind unbind
• The bucket99_status servlet returns an HTML document describing the status of all currently-loaded Bucket99 drivers.