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Data Mapper mediator is a data mapping solution that can be integrated into a mediation sequence. It converts and transforms one data format to another, or changes the structure of the data in a message. It provides a WSO2 Developer Studio-based tool to create a graphical mapping configuration and generates the files required to execute this graphical mapping configuration by the WSO2 Data Mapper engine.

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Table of Contents
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Prerequisites

You need to install the WSO2 Developer Studio ESB Tool 5.0.0 to use the Data Mapper mediator. For instructions on installing this WSO2 ESB Tooling Plugin, see Installing WSO2 ESB Tooling.

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Parameter nameDescription
Mapping ConfigurationThe file, which contains the script file that is used to execute the mapping. You need to create a mapping configuration file using the Dev Studio-based Tooling plugin, and store it either in the Configuration Registry or Governance Registry, to select and upload it from here.
Input SchemaJSON schema, which represents the input message format. You need to create an input schema file using the Dev Studio-based Tooling plugin, and store it either in the Configuration Registry or Governance Registry to select and upload it from here.
Output SchemaJSON schema, which represents the output message format. You need to create an output schema file using the Dev Studio-based Tooling plugin, and store it either in the Configuration Registry or Governance Registry to select and upload it from here.
Input TypeExpected input message type (XML/JSON/CSV)
Output TypeTarget output message type (XML/JSON/CSV)
Info
titleNote

You can configure the mediator using XML. Click switch to source view in the Mediator window.

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WSO2 Data Mapper consists of two components. They are Data Mapper Tooling and Data Mapper Engine.

Data Mapper Tooling 

Data Mapper Tooling component is the interface used to create configuration files that are required by the Data Mapper Engine to execute the mapping. Following three configuration files are needed by the Data Mapper engine. 

  • Input schema file
  • Output schema file
  • Mapping configuration file

These three files are generated by the Data Mapper Tool and saved in a Registry Resource project, which you deploy in a WSO2 server as shown in the example below.

generated configuration filesImage Modified

Info

The .datamapper and .datamapper_diagram files as shown in the example above contain meta data related to the Data Mapper diagram. They are ignored when you deploy the project to a server to be used by the Data Mapper Engine. Only the two schema files and the .dmc (Data Mapper Configuration) get deployed.

Input and output schema files

Input and output schema files are custom-defined JSON schemas that define the input/output format of input/output messages. The Data Mapper tool generates them when loading the input and output files as shown below.

Info

You can also create the input and output JSON Schemas manually using the Data Mapper Diagram Editor. For instructions, see Creating a JSON Schema Manually.

select load input optionImage Modified

select input format

You can load the following input/output message formats:

Info
When loading a sample input XML file, you cannot have the default namespace (i.e. without a prefix in the namespace element). Also, you need to use the same prefix in all occurrences that refer to the same namespace within one XML file. For example, see the use of the prefix axis2ns11 in the example below.

 

Expand
titleSample input XML file
Code Block
languagexml
<?xml version="1.0" encoding="utf-8"?>
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/">
<soapenv:Header>
    <axis2ns11:LimitInfoHeader xmlns:axis2ns11="urn:partner.soap.sforce.com">
        <axis2ns11:limitInfo>
            <axis2ns11:current>42336</axis2ns11:current>
            <axis2ns11:limit>83000</axis2ns11:limit>
            <axis2ns11:type>API REQUESTS</axis2ns11:type>
        </axis2ns11:limitInfo>
    </axis2ns11:LimitInfoHeader>
</soapenv:Header>
<soapenv:Body>
    <axis2ns11:records xmlns:axis2ns11="urn:partner.soap.sforce.com" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:type="sf:sObject">
    <sf:type xmlns:sf="urn:sobject.partner.soap.sforce.com">Account</sf:type>
    <sf:Id xmlns:sf="urn:sobject.partner.soap.sforce.com">001E0000002SFO2IAO</sf:Id>
    <sf:CreatedDate xmlns:sf="urn:sobject.partner.soap.sforce.com">2011-03-15T00:15:00.000Z</sf:CreatedDate>
    <sf:Id xmlns:sf="urn:sobject.partner.soap.sforce.com">001E0000002SFO2IAO</sf:Id>
    <sf:Name xmlns:sf="urn:sobject.partner.soap.sforce.com">WSO2</sf:Name>
</axis2ns11:records>
</soapenv:Body>
</soapenv:Envelope>
  • XML: to load a sample XML file
  • JSON: to load a sample JSON file
  • CSV: to load a sample CSV file with column names as the first record
  • XSD: to load an XSD file, which is an actual schema for XML files
  • JSONSCHEMA: to load a WSO2 Data Mapper JSON schema
  • CONNECTOR: to use Data Mapper with WSO2 ESB Connectors. Connectors will contain JSON schemas for each operation that defines the message formats to which it will respond and expect. Therefore, when you integrate connectors in a project this Connector option searches through the workspace and find the available Connectors. Then, you can select the respective Connector in the operation, so that the related JSON schema will be loaded for the Data Mapper by the tool.
Mapping configuration file

This is a JavaScript file generated by looking at the diagram you draw in the Data Mapper Diagram Editor by connecting input elements to output elements. Every operation you define in the diagram gets converted to a JavaScript operation.

Data Mapper Engine

You need the following information to configure the Data Mapper Engine:

  • Input message type
  • Output message type
  • Input schema Java Scripting API
  • Output schema
  • Mapping configuration

At the runtime, the Data Mapper Engine gets the input message and the runtime variable map object and outputs the transformed message. The Data Mapper Engine uses the Java Scripting API, t o execute the mapping configuration. Therefore, if your runtime is JAVA 7, it uses the Rhino JS Engine and if your runtime is JAVA 8, it uses the Nashorn JS engine.

When you use JAVA 7, there are several limitations in the Rhino engine that directly affects the Data mapper Engine. There are several functions that Rhino does not support. For example, String object functions like startsWith() and endsWith(). Therefore, the Rhino engine may have limitations in executing those when using custom functions and operators.

Using product-specific runtime variables

Also, the Data Mapper engine allows you to use runtime product-specific variables in the mapping. The intermediate component should construct a map object containing runtime product-specific variables and send it to the Data Mapper Engine, thereby, when the mapping happens in the Data Mapper Engine, these variables become available.

For example, the Data Mapper mediator provides ESB properties like  axis2/transport/synapse/axis2client/operation/.. In the Data Mapper diagram, you can use the  Property operator  and define the scope and the property name and use it in the mapping. Then, the Data Mapper mediator will identify the required properties to execute the mapping and populate a map with the required properties and will send it to the Data Mapper Engine. 

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Data Mapper element and attribute types

Following are the element and attribute types that are supported by the Data Mapper.

  • {} - represents object elements
  • [] - represents array elements
  • <> - represents primitive field values
  • A - represents XML attribute values

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Data Mapper operations

The operations palette placed in the left-hand side of the WSO2 Data Mapping Diagram Editor displays the operations that the Data Mapper supports as shown below.

Image Modified

You can drag and drop these operations to the Editor area. There are six categories of operations as follows:

  • Links
  • Common
  • Arithmetic
  • Conditional
  • Boolean
  • Type Conversion
  • String

DataMapperLink.gifImage Modified   Data Mapping Link:  maps elements with other operators and elements.

Common

Constant Constant: defines String, number or boolean constant values.

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GlobalVariable Global Variable: instantiates global variables that you can access from anywhere. 

Compare Compare: compares two inputs in the mapping.

Arithmetic

Add Add: adds two numbers.

Subtract Subtract: subtracts two or more numbers.

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Max Max: derives the maximum number from given inputs

Conditional

IfElseImage Modified   IfElse:  uses a condition and selects one input from given two.

Boolean 

AND AND: performs the boolean AND operation on inputs. 

OR OR: performs the boolean OR operation on inputs.

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Code Block
languagejava
{
  "books": {
    "book": {
      "id": "001",
      "author": "Writer",
      "title": "Great book on nature",
      "price": "44.95"
    }
  }
}

Samples

For a sample that demonstrates how to use the Data Mapper mediator, see: