This expression is used to define top-level process definitions as well as subprocess definitions. Top-level process definition require the 'revision' attribute to be set. The 'name' attribute is mandatory for top-level and sub process definitions. http://www.openwfe.org/docbook/build/ch06s02.html#expression_process_definition The 'sequence' expression defines a list of children expressions that have to be evaluated sequentially. http://www.openwfe.org/docbook/build/ch06s02.html#expression_sequence The children of this expression will be executed in parallel. Concurrence has various attributes for determining how the synchronization at the end of the parallel executions has to happen. http://www.openwfe.org/docbook/build/ch07s03.html Currently, this attribute should be omitted or always set to 'generic'. Future versions of OpenWFE may make use of it. When this attribute is omitted, the concurrence will wait for all the branches to reply before resuming. If it's set to 1, for example, after one branch replied the concurrence will be considered as over and the remaining branches will be cancelled (or forgotten if the 'remaining' attribute is set to 'forget'). 'over-if' may contain a string which is evaluated each time a branch replies. If the content evaluation yields 'true', the concurrence will be over, and the remaining children will be cancelled or forgotten. 'over-if' and 'count' may be used simultaneously. Dictates which incoming branch reply has the priority when the values of the workitems are 'reconciliated'. For example, if 'merge' yields the value 'last'. The fields of the workitem of the last branch that replied will win (the merge). The value of the 'merge-type' attribute may either be 'mix' or 'override'. In conjunction with the 'merge' attribute it tells the engine if workitems of a merge winner should 'override' completely the workitems of the losers or if they should 'mix' (composing a new workitem, where the fields (and not the whole workitem) of the winner will have priority. This 'merge-type' attribute could maybe have been called 'merge-granularity'. The default value for this attribute is 'cancel', meaning that when the synchronization is over ('count' or 'over-if' requesting it), the remaining children will get cancelled. Or if this 'remaining' attribute is set to 'forget' they'll simply get forgotten and continue to live (as dead ends). An iterator takes care of executing its children one or more item. It's the equivalent of the 'for' loop in classical programmation. 'concurrent-iterator' will execute all its iterations concurrently whereas 'iterator' will execute them sequentially. http://www.openwfe.org/docbook/build/ch07s14.html#pat_expression_iterator The 'concurrent-iterator' executes all of its iteration concurrently, it's like a concurrent 'for' loop. http://www.openwfe.org/docbook/build/ch07s13.html A participant is anyone/anything taking part in a process. Participants are usually defined in the file etc/engine/participant-map.xml The main attribute of a participant expression is 'ref' which refers to a participant name in the participant map. Engines are participant too. http://www.openwfe.org/docbook/build/ch06s02.html#expression_participant An absolute reference to a participant (by its name in the participant map). The name of the participant that will receive the workitem is the value of the given field. The given variable should hold the name of the participant that will receive the workitem. If 'ref' isn't present and if neither 'field-ref' nor 'variable-ref' holds a value for the participant name, this attribute holds the 'default' participant name. A comma separated list of participant names that are tried one after the other until delivery succeeds to one of them. This list is tried only if other references yielded failed deliveries to their participant. This attribute helps define 'fail-over participants'. A filter determines which permissions are set on the fields of a workitem emitted to the participant. The attribute filter should contain the name of a filter defined by a 'filter-definition' expression. As engines deliver workitem to participants, they lose control over the workitem. The participant may never reply. This attribute sets locally after how much time the engine shall consider the workitem as 'lost' and resume the flow. If the timeout is set to '-1', 'no' or 'none', the engine will never consider the workitem as lost. The flow will resume with a copy of the workitem as it was just before being sent to the participant. The flow will not be considered as failed and 'else-ref' participants won't get triggered. A small help attribute. Its value is set as the content of the field named '__description__' just before being sent to the engine. When the workitem comes back, the field is cleaned (removed). This attribute is useful for setting task descriptions for the participant (could be useful for a human participant as well as for an 'automatic' participant). If this attribute is present and set to 'true', the engine will resume the flow and 'forget' about having sent a workitem to the participant. Can be useful for implementing advanced notification mechanisms. The 'cancel-process' expression will cancel the whole workflow instance upon being evaluated. Use it with care : it's explicit termination of a flow. http://www.openwfe.org/docbook/build/ch06s09.html#expression_cancel_process The 'forget' expression simply applies its child expression (in a separate execution thread) and immediately replies. It may be seen as a way of forking an independent process branch. http://www.openwfe.org/docbook/build/ch06s09.html#expression_forget 'lose' will apply its child expression but will never reply, it may still get cancelled (whereas a 'forget' branch having immediately replied, cannot get cancelled). 'lose' makes sense within a concurrence to tag a branch as 'we don't care about its reply and we'll cancel it when the non-lost branch will have replied. http://www.openwfe.org/docbook/build/ch06s09.html#expression_lose The 'rotate' expression turns a vertical workitem field into an horizontal one and vice-versa. A typical horizontal workitem field is a list of strings stored with comma separators. The typical vertical workitem field is an instance of ListAttribute. http://www.openwfe.org/docbook/build/ch06s09.html#expression_rotate This attribute is mandatory, it points to the field whose value should get rotated. If the attribute 'to-field' is not present. The field named here will be the source and the target of the rotation operation. If this attribute is present, the rotation operation will store its result in the field named here. If this field is set to 'yes' or 'true', the rotated strings will be trimmed. The default separator is the comma ",". This attribute may be used to specify another one. Do not use a regular expression here. Allows to save the current workitem to a variable or into a file (as XML). http://www.openwfe.org/docbook/build/ch06s09.html#expression_save This attribute states the name of the variable that will be holding a copy of the current workitem. Gives the path to the file that will hold an XML version of the current workitem. The path to this file may be absolute or relative (to the engine working directoy). Restores a workitem saved into a variable or into a file as the current workitem. http://www.openwfe.org/docbook/build/ch06s09.html#expression_restore The name of the variable that should contain the stored workitem. This attribute may either take the value 'current' or 'restored'. In case of conflicting mapping for fields, 'current' means that the current workitem has the priority, 'restored' means the stored workitem will win. Merge conflicts can be avoided by putting the stored workitem attribute tree as a branch of the current workitem. The attribute (field) holding that 'branch' is specified here. Restores the workitem from the absolute or relative path given here. If this attribute is set to 'true' or 'yes', the file containing the stored workitem will be removed after the restore operation was successful. The 'case' expression is a kind of 'multi-if'. Its children are a set of pairs (conditional expression + classical expression) followed by an optional classical expression (an else clause). At execution, going from top to bottom, each conditional expression is considered, if it evaluates to 'true', the classical expression immediately following the conditional is evaluated. The case expression is then over. If no conditional evaluated to true and if it's present, the final and optional classical expression is evaluated. http://www.openwfe.org/manual/ch06s05.html#expression_case 'breaks' out of a loop or a cursor expression. http://www.openwfe.org/docbook/build/ch06s03.html#expression_curloo_break_and_co 'breaks' out of a loop or a cursor expression (an alias for 'break'). http://www.openwfe.org/docbook/build/ch06s03.html#expression_curloo_break_and_co Gets back at the beginning of a cursor or loop expression, 'rewinds' it. http://www.openwfe.org/docbook/build/ch06s03.html#expression_curloo_break_and_co Gets back at the beginning of a cursor or loop expression, 'rewinds' it. An alias for 'rewind'. http://www.openwfe.org/docbook/build/ch06s03.html#expression_curloo_break_and_co Steps back one expression in containing the cursor or loop expression. http://www.openwfe.org/docbook/build/ch06s03.html#expression_curloo_break_and_co When stepping more than one expression. Awaits an integer value. Steps forward one expression in the containing cursor or loop expression. http://www.openwfe.org/docbook/build/ch06s03.html#expression_curloo_break_and_co When stepping more than one expression. Awaits an integer value. Checks whether a field or a variable is set. http://www.openwfe.org/docbook/build/ch06s05.html#expression_defined Checks whether a field or a variable is not set at all. http://www.openwfe.org/docbook/build/ch06s05.html#expression_undefined this attribute, if present, should contain the name of a workitem field. If this field is present in the workitem, the 'undefined' expression will evaluate to 'false'. If the value named here is set (has a value), the 'undefined' expression will evaluate to 'true'. The 'eval' expression may extract OpenWFE 'code' from a workitem field (see the 'field' attribute) or from a nested OpenWFE constuct and evaluate it on the fly. http://www.openwfe.org/docbook/build/ch06s09.html#expression_eval When the field attribute is set, the 'eval' expression will read the code to evaluate from the field named here. Any nested content will be ignored.