ResetContentDescriptor node

Use the ResetContentDescriptor node to request that the message is reparsed by a different parser.

This topic contains the following sections:

Purpose

If you specify MRM as the new parser, you can also specify a different message template (message set, message type, and message format). This node does not reparse the message, but the properties that you set for this node determine how the message is parsed when it is next reparsed by the message flow.

The node associates the new parser information with the input message bit stream. If the message has been parsed already to create a message tree, and the contents of the tree have been modified (for example, by a Compute node), the ResetContentDescriptor node must re-create the bit stream from the message tree by calling the current parser.

If your message flow has updated the message before it is received by the ResetContentDescriptor node, ensure that the changed message contents are still valid for the current parser. If the contents are not valid, the parser generates an error when it attempts to re-create the bit stream from the message tree, and the ResetContentDescriptor node raises an exception. For example, if you have added a new field to a message in the MRM domain, and the field is not present in the model, the re-creation of the bit stream fails.

The ResetContentDescriptor node does not:

  • Change the message content; it changes message properties to specify the way in which the bit stream is parsed next time that the parser is started.
  • Convert the message from one format to another; for example, if the incoming message has a message format of XML and the outgoing message format is CWF, the ResetContentDescriptor node does not do any reformatting. It starts the parser to re-create the bit stream of the incoming XML message, which retains the XML tags in the message. When the message is reparsed by a subsequent node, the XML tags are not valid and the reparse fails.

The ResetContentDescriptor node is contained in the Transformation drawer of the palette, and is represented in the workbench by the following icon:

ResetContentDescriptor node icon

Using this node in a message flow

For an example of how to use this node, assume that you want to swap between the BLOB and the MRM domains. The format of an incoming message might be unknown when it enters a message flow, therefore the BLOB parser is started. Later on in the message flow, you might decide that the message is predefined as a message in the MRM domain, and you can use the ResetContentDescriptor node to set the correct values to use when the message is parsed by a subsequent node in the message flow.

The following table shows typical ResetContentDescriptor node properties.
Property Value
Message domain MRM
Reset message domain Selected
Message set DH53CU406U001
Reset message set Selected
Message type m_MESSAGE1
Reset message type Selected
Message format CWF
Reset message format Selected

The Message domain is set to MRM, and the MRM parser is started when the message is next parsed. The Message set, Message type, and Message format are the message template values that define the message model, and all of the reset check boxes are selected because all of the properties need to change.

The ResetContentDescriptor node causes the BLOB parser that is associated with the input message to construct the physical bit stream of the message (not the logical tree representation of it), which is later passed to the MRM parser. The MRM parser then parses the bit stream using the message template (Message set, Message type, and Message format) specified in this ResetContentDescriptor node.

Configuring the ResetContentDescriptor node

When you have put an instance of the ResetContentDescriptor node into a message flow, you can configure the node. For more information, see Configuring a message flow node. The properties of the node are displayed in the Properties view. To display the properties of the node in the Properties dialog, either double-click the node, or right-click the node and click Properties.

All mandatory properties for which you must enter a value (those that do not have a default value defined) are marked with an asterisk.

  1. Optional: On the Description tab, enter a Short description, a Long description, or both. You can also rename the node on this tab.
  2. On the Basic tab:
    1. To use a different parser associated with the message, specify the new domain in the Message domain property:
      • MRM
      • XML
      • XMLNS
      • XMLNSC
      • JMS
      • JMSStream
      • IDOC
      • MIME
      • BLOB

      You can also specify a user-defined parser if appropriate.

      You must also select the Reset message domain check box.

    2. If the MRM or IDOC parser is to reparse the message, specify the other properties of the model that are to be associated with the input message, and select the relevant reset check box beneath each field. If the parser is associated with the input message already, specify only the properties that are to change.
      1. Define the Message set. Choose a value from the list of available message sets (the name and identifier of the message set are shown), and select the Reset message set check box.
      2. For MRM only, define the identifier of the message in Message type. You can find this identifier in the properties of the message in the editor view. You specified the identifier when you created the message. Enter the identifier exactly as shown in the message properties, and select the Reset message type check box.
      3. For MRM and IDOC, define the Message format. This property specifies the physical format for the parser. You can select one of the formats from the list (which lists the identifiers of those formats that you have defined on the Message set specified previously), and select Reset message format.

      These properties set the message domain, message set, message type, and message format values in the message header of the message that you want to pass through the ResetContentDescriptor node. However, these actions are taken only if suitable headers already exist. If the message does not have an MQRFH2 header, the node does not create one.

      Leave Message set, Message type, and Message format blank if you have specified the XML, JMS, MIME, or BLOB parser.

  3. On the Parser Options tab:
    1. Parse timing is, by default, set to On Demand, which causes parsing of the message to be delayed.

      If you change this value to Immediate, partial parsing is overridden and everything in the message is parsed and validated, except those complex types with a composition of Choice or Message that cannot be resolved at the time. If you change this value to Complete, partial parsing is overridden and everything in the message is parsed and validated; complex types with a composition of Choice or Message that cannot be resolved at the time cause a validation failure.

      For more details, see Parsing on demand.

    2. Select Use MQRFH2C compact parser for MQRFH2 header if you want the MQRFH2C parser to be used. By default, this check box is cleared, which means that the compact parser is not used.
    3. If you are using the XMLNSC parser, set values for the properties that determine how the XMLNSC parser operates. For more information, see Manipulating messages in the XMLNSC domain.
  4. On the Validation tab, set the validation properties if you want the parser to validate the body of messages against the Message set. (If a message is propagated to the Failure terminal of the node, it is not validated.)

    For more details, see Validating messages and Validation properties.

Terminals and properties

The ResetContentDescriptor node terminals are described in the following table.

Terminal Description
In The input terminal that accepts a message for processing by the node.
Failure The output terminal to which the message is routed if an error is detected by the node.
Out The output terminal to which the message is routed if a new parser is identified by the properties.

The following tables describe the node properties. The column headed M indicates whether the property is mandatory (marked with an asterisk if you must enter a value when no default is defined); the column headed C indicates whether the property is configurable (you can change the value when you add the message flow to the BAR file to deploy it).

The Description properties of the ResetContentDescriptor node are described in the following table.

Property M C Default Description
Node name No No The node type The name of the node.
Short description No No   A brief description of the node.
Long description No No   Text that describes the purpose of the node in the message flow.

The Basic properties of the ResetContentDescriptor node are described in the following table.

Property M C Default Description
Message domain No No   The message domain that is associated with the message that you want to reparse.
Reset message domain Yes No Cleared If you select the reset check box, the Message domain property is reset. In this case, if you do not select a value for the Message domain property, the Message domain property value is BLOB.
Message set No No   The message set that is associated with the message that you want to reparse.
Reset message set Yes No Cleared If you select the reset check box, the Message set property is reset. In this case, if you do not select a value for the Message set property, the Message set property value is blank.
Message type No No   The message type that is associated with the message that you want to reparse.
Reset message type Yes No Cleared If you select the reset check box, the Message type property is reset. In this case, if you do not select a value for the Message type property, the Message type property value is blank.
Message format No No   The message format that is associated with the message that you want to reparse.
Reset message format Yes No Cleared If you select the reset check box, the Message format property is reset. In this case, if you do not select a value for the Message format property, the Message format property value is blank.

The Parser Options properties of the ResetContentDescriptor node are described in the following table.

Property M C Default Description
Parse timing No No On Demand This property controls when the reparsed message is parsed. Valid values are On Demand, Immediate, and Complete.

For a full description of this property, see Parsing on demand.

Use MQRFH2C compact parser for MQRFH2 domain No No Cleared This property controls whether the MQRFH2C Compact Parser, instead of the MQRFH2 parser, is used for MQRFH2 headers.
Use XMLNSC compact parser for XMLNS domain No No Cleared This property controls whether the XMLNSC Compact Parser is used for messages in the XMLNS Domain. If you set this property, the message data appears under XMLNSC in nodes that are connected to the output terminal when the input MQRFH2 header or Domain is XMLNS.
Retain mixed content No No Cleared This property controls whether the XMLNSC parser creates elements in the message tree when it encounters mixed text in the reparsed message. If you select the check box, elements are created for mixed text. If you clear the check box, mixed text is ignored and no elements are created.
Retain comments No No Cleared This property controls whether the XMLNSC parser creates elements in the message tree when it encounters comments in the reparsed message. If you select the check box, elements are created for comments. If you clear the check box, comments are ignored and no elements are created.
Retain processing instructions No No Cleared This property controls whether the XMLNSC parser creates elements in the message tree when it encounters processing instructions in the reparsed message. If you select the check box, elements are created for processing instructions. If you clear the check box, processing instructions are ignored and no elements are created.

The Validation properties of the ResetContentDescriptor node are described in the following table. For a full description of these properties, see Validation properties.

Property M C Default Description
Validate No Yes None This property controls whether validation takes place. Valid values are None, Content, Content and Value, and Inherit.
Failure action No No Exception This property controls what happens if validation fails. You can set this property only if you set Validate to Content and Value or Content. Valid values are User Trace, Local Error Log, Exception, and Exception List.
Include all value constraints No No Selected You cannot edit this property. If you select this check box, basic value constraint checks are included in Content and Value validation.
Fix No No None You cannot edit this property. Valid values are None, and Full.
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Copyright IBM Corporation 1999, 2009Copyright IBM Corporation 1999, 2009.
Last updated : 2009-01-07 15:20:10

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