The Application Level Events (ALE) Specification, Version 1.0 - GS1
The Application Level Events (ALE) Specification, Version 1.0 - GS1
The Application Level Events (ALE) Specification, Version 1.0 - GS1
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
2710<br />
2711<br />
2712<br />
2713<br />
2714<br />
2715<br />
2716<br />
2717<br />
2718<br />
2719<br />
2720<br />
2721<br />
2722<br />
2723<br />
2724<br />
2725<br />
2726<br />
2727<br />
2728<br />
2729<br />
2730<br />
2731<br />
2732<br />
2733<br />
2734<br />
2735<br />
2736<br />
2737<br />
2738<br />
2739<br />
2740<br />
13.2.1.2 Description<br />
1. <strong>The</strong> client calls the define method of the <strong>ALE</strong> interface. <strong>The</strong> ECSpec<br />
specifies that the event cycle is to begin using repeatPeriod as the<br />
boundary specification and to end using duration as the boundary<br />
specification (but any valid boundary conditions could be specified). <strong>The</strong><br />
ECReportSpec and ECFilterSpec contained within the ECSpec are<br />
defined to include the EPC data sent later in step 3.<br />
2. <strong>The</strong> client calls the subscribe method of the <strong>ALE</strong> interface, including a<br />
URI that identifies the client itself as the destination for the ECReports. At<br />
this point the ECSpec is considered “Requested.” Since the start condition is<br />
given by repeatPeriod, the ECSpec immediately transitions to the<br />
“Active” state.<br />
3. During period1 no new tags (additions) were reported by the Reader, and no<br />
deletions were noted, thus no ECReports is generated.<br />
4. In period2, an EPC that does meet the filter conditions specified in the<br />
ECSpec is reported to the <strong>ALE</strong> layer by one of the Readers indicated in the<br />
ECSpec.<br />
5. At the end of period2, the requested ECReports is generated and sent to the<br />
client.<br />
6. In period3, no EPCs are reported, and no ECReports are generated.<br />
7. In period4 the client calls the unsubscribe method of the <strong>ALE</strong> interface.<br />
As this client is the only subscriber, the ECSpec transitions to the<br />
“Unrequested” state, and no further ECReports are generated.<br />
8. Because the ECSpec is Unrequested, the client can undefine the ECSpec<br />
without any error.<br />
13.2.2 Scenario 1b: Indirect Subscription<br />
<strong>The</strong> scenario shown below involves a client application specifying the EPC data that is of<br />
interest to another observer. After specifying the ECSpec, the client subscribes a third<br />
party observer to receive the resulting ECReports. <strong>The</strong> ECSpec shown in this<br />
scenario specifies the event cycle to start and stop using a trigger mechanism. This is a<br />
normal scenario involving no errors.<br />
Copyright © 2005, 2004 EPCglobal Inc, All Rights Reserved. Page 66 of 71
Change language