MessageNode

XPathNode

XPathNode parses XML payload of JMS messages and retrieves data from the XML payload according to the predifined XPath expressions. It then sets them into message's properties. The original XML payload should be always stored in the message body. XPathNode will not modify the XML payload. There are three outlinks, done for all parsed messages, nohit for those messages not belonging to any predefined rulesets, failure for those messages failed in the XPath evaluations.

XPathNode contains a number of predefined rulesets. These rulesets categorize messages into non-overlapping groups. Therefore, each rule defines a unique message group. The ruleset also defines the XPath expressions. The original XML payload should be always stored in the message body. Due to JMS specifications, you have to clear user properties before resetting them on a readonly message. You can specify ResetOption in a ruleset so that the message header will be reset for modifications. Its value is 0 for no reset, 1 for optional reset and 2 for guaranteed reset.

XPathNode supports dynamic setting of xpath expressions. It means you can reference properties of the message in your xpath expressions. XPathNode will retrieve the data from the incoming message and compile the expressions before the evaluation.

XPathNode allows one of the xpath expressions to select a list of items. In this case, ListKey has to be defined. It specifies the key for that special xpath expression. The expression will be applied in the context of XPathConstants.NODESET. XPathNode will retrieves the data from each item and appends them one by one with a predefined delimiter.

XPathNode always adds an extra ruleset for the nohit messages. This nohit ruleset is always the first ruleset with the id of 0. On the node level, DisplayMask and StringProperty control the display result of outgoing messages.

You are free to choose any names for the three fixed outlinks. But XPathNode always assumes the first outlink for done, the second for failure and the last for nohit.

The XPath evaluation is executed via the pre-defined rulesets. Therefore, the configuration of the rulesets is critical to the operations of XPathNode. Here are complete properties of rulesets for XPathNode.

Property Name Data Type Requirement Description Examples

Name alphanumeric with no spaces mandatory name of the ruleset event

ResetOption integer optional option to reset properties 2 (default: 0)

XPath map mandatory for XPath only for resetting properties of messages see example

ListKey string key name of the XPath expression for list aggregation to select a list of items ID

Delimiter string required for list aggregation delimiter used to separate listed data ,

PreferredOutLink alphanumeric with no spaces mandatory for bypass only name of the preferred outlink bypass

FormatterArgument list optional list of post format operations see example

JMSPropertyGroup list optional list of pattern groups on properties to select messages see example

XJMSPropertyGroup list optional list of pattern groups on properties to exclude messages see example

PatternGroup list optional list of pattern groups on body to select messages see example

XPatternGroup list optional list of pattern groups on body to exclude messages see example

StringProperty map optional for setting the user properties on the messages see example

where XPath specifies the details of the XPath expressions. PreferredOutLink can be defined for bypass rulesets only. In this case, the messages of the group will not be parsed. Here is an example for the bypass ruleset:

Property Name	Data Type	Requirement	Description	Examples
Name	alphanumeric with no spaces	mandatory	name of the ruleset	event
ResetOption	integer	optional	option to reset properties	2 (default: 0)
XPath	map	mandatory for XPath only	for resetting properties of messages	see example
ListKey	string	key name of the XPath expression for list aggregation	to select a list of items	ID
Delimiter	string	required for list aggregation	delimiter used to separate listed data	,
PreferredOutLink	alphanumeric with no spaces	mandatory for bypass only	name of the preferred outlink	bypass
FormatterArgument	list	optional	list of post format operations	see example
JMSPropertyGroup	list	optional	list of pattern groups on properties to select messages	see example
XJMSPropertyGroup	list	optional	list of pattern groups on properties to exclude messages	see example
PatternGroup	list	optional	list of pattern groups on body to select messages	see example
XPatternGroup	list	optional	list of pattern groups on body to exclude messages	see example
StringProperty	map	optional	for setting the user properties on the messages	see example

{
  ...
  "Ruleset": [{
    "Name": "bypass",
    "PreferredOutLink": "BYPASS",
    "JMSPropertyGroup": [{
      "JMSType": "^score$"
    }]
  }],
  ...
}

where it routes the messages to the outlink of BYPASS.

Here is an example of the XPath ruleset.

{
  ...
  "Ruleset": [{
    "Name": "script",
    "JMSPropertyGroup": [{
      "operation": "^start$"
    }],
    "ResetOption": "1",
    "XPath": {
      "ActionScript": "/*/StartScript"
    }
  },{
  ...
  }],
  ...
}

where it extracts the content from the XML payload and sets the value on the property of ActionScript.

Here is an example of XPathNode:

{
  "Name": "node_xpath",
  "ClassName": "org.qbroker.node.XPathNode",
  "Description": "xparse messages",
  "Operation": "evaluate",
  "LinkName": "root",
  "Capacity": "6",
  "DisplayMask": "0",
  "Debug": "19",
  "Ruleset": [{
    "Name": "test",
    "ResetOption": "1",
    "JMSPropertyGroup": [{
      "JMSType": "."
    }],
    "XPath": {
      "MTC": "//MediaTimePoint",
      "RTC": "//MediaRelTimePoint",
      "Millis": "//MediaTimeMillis"
    },
  }],
  "OutLink": [
    "parsed",
    {
      "Name": "failure",
      "Capacity": "24",
      "Partition": "0,6"
    },{
      "Name": "nohit",
      "Capacity": "24",
      "Partition": "0,6"
    }
  ]
}