[bpel4people] NEW ISSUE: B4P spec doesn't support sequential routingpattern

[Ravi Rangaswamy <ravi.rangaswamy@oracle.com>]

TARGET: WS-HT, General

DESCRIPTION: WS-HT should support sequential routing pattern. In the 
current WS-HT spec, people assignments are singular in notion. The 
potential owners in the sequential pattern can either be done through 
logical people groups, literals or an expression.

Use Case: Consider an approval process for OnBoarding where a task has 
to be approved by following a management chain. Only if one user 
completes the task, it is assigned to the next in the chain. WS-HT 
should support the assignment of tasks to a sequence of users/groups.

RELATED ISSUES:
· Support for routing patterns and policies
· Support for single routing pattern
· Support for parallel routing pattern

PROPOSAL: Provide a mechanism to assign the task sequentially to 
users/groups by introducing a sequential routing pattern. In the 
sequential pattern, the task is assigned to either a list of users or 
groups. In each assignment, if there are multiple potential owners than 
one can claim the task and become the actual owner. After the actual 
user completes the task, it is assigned to the next users/groups in the 
sequential pattern.

The sequential routing pattern can either represent a list of sequential 
users/groups or a management chain.

In the list of users/groups case, the users/groups to approve the task 
are specified in the <htd:from> element. After each task owner completes 
the task, the task will be assigned to next user(s)/group(s) in the 
list. The order of the htd:from children will be preserved and used in 
the ordering of the user/groups evaluated from the list of htd:from 
elements.

Management chain indicates a sequence of task assignment that is a 
result of computing the management chain in the associated user 
directory. The management chain contains the optional first task 
assignment. This task assignment could result in one or more potential 
owners. If there are multiple potential owners, one user from the list 
of potential owners can claim the task and become the actual owner. When 
the actual owner completes the task, the actual owner is used as the 
base user to compute the management chain. If the first task assignment 
is not present, the user who previously completed the task will be used 
to compute the management chain. When the first task assignment is 
specified in the management chain, optionally the actual owner could 
also be specified to indicate who should be the default actual owner in 
case there is more than one user in the potential owners list. The 
management chain list is controlled by the 2 parameters:
1. Levels: The number of levels in the management chain to actually 
assign the task to. The count of level starts from the first assignment 
resulting from the evaluation of the management chain. This is an 
optional configuration.
2. Highest Title of Approver: The title of the last (highest) user in 
the management chain. This is an optional configuration.

Syntax

<xsd:complexType name="tSequential">
<xsd:complexContent>
<xsd:extension base="tExtensibleElements">
<xsd:sequence>
<xsd:element name="list" type="tList"/>
</xsd:sequence>
<xsd:attribute name="name" type="xsd:string"
use="optional"/>
</xsd:extension>
</xsd:complexContent>
</xsd:complexType>

<xsd:complexType name="tList">
<xsd:complexContent>
<xsd:extension base="tExtensibleElements">
<xsd:sequence>
<xsd:choice maxOccurs=”1”>
<xsd:element name="from" type="tFrom"
minOccurs="0"
maxOccurs="unbounded"/>
<xsd:element name="managementChain"
type="tManagementChain"
minOccurs="0" maxOccurs="1"/>
</xsd:choice maxOccurs=”1”>
</xsd:sequence>
</xsd:extension>
</xsd:complexContent>
</xsd:complexType>

<xsd:complexType name="tManagementChain">
<xsd:complexContent>
<xsd:extension base="tExtensibleElements">
<xsd:sequence>
<xsd:element name="from" type="tFrom"
minOccurs="0"
maxOccurs="unbounded"/>
<xsd:element name="levels" type="xsd:string"
minOccurs="1"/>
<xsd:element name="title" type="xsd:string"
minOccurs="0"/>
</xsd:sequence>
</xsd:extension>
</xsd:complexContent>
</xsd:complexType>

Examples

In the example below, assuming that the task input ClaimApprovalRequest 
has 3 claimProcessingAgents children – jlondon, jstein, wfaulk, the task 
will first be assigned to jlondon. After jlondon completes the task, it 
will be assigned to jstein. After jstein completes the task, it will be 
assigned to wfaulk.

<htd:sequential name="Claim Processing Agents">
<htd:list>
<htd:from>
htd:getInput("ClaimApprovalRequest")/claimProcessingAgents
</htd:from>
</htd:list>
</htd:sequential>

In the example below, the task will first be assigned to user achrist. 
After achrist completes the task, it will be assigned to achrist’s 
manager jlondon. After jlondon completes the task, it will be assigned 
to his manager jstein. The management chain will stop at that level 
because it has gone 3 levels. If jlondon where the ‘Vice President’, the 
management chain will stop with jlondon.

<htd:sequential name="Claim Processing Review">
<htd:list>
<htd:managementChain>
<htd:from>
<htd:literal>
<htd:organizationalEntity>
<htd:users>
<htd:user>achrist</htd:user>
</htd:users>
</htd:organizationalEntity>
</htd:literal>
</htd:from>
<htd:levels>number(3)</htd:levels>
<htd:title>string('Vice President')</htd:title>
</htd:managementChain
</htd:list>
</htd:sequential>