Formats

The mapping between Java objects to DataWeave types is quite simple:

Java developers use the 'class' metadata key as hint for what class needs to be created and sent as an input. If this is not explicitly defined, DataWeave tries to infer from the context or it assigns it the default values:

The above code defines the type of the required input as an instance of 'com.anypoint.df.pojo.User'.

In order to put an enum value in a java.util.Map, the DataWeave java module defines a custom type called :enum. It allows you to specify that a given string should be handled as the name of a specified enum type. It should always be used with the class property with the java class name of the enum.

In the Transform Message component, you can define a Java type through the following methods:

CSV content is modeled in DataWeave as a list of objects, where every record is an object and every field in it is a property. For example:

In CSV you can assign any special character as the indicator for separating fields, toggling quotes, or escaping quotes. Make sure you know what special characters are being used in your input, so that DataWeave can interpret it correctly.

When you define an input of type CSV, there are a few optional parameters you can add in the XML definition of your Mule project to customize how the data is parsed.

You can set theses properties through the XML of your Mule project:

Alternatively, you can set the properties through the UI of the Transform Message component:

See To Define Input and Output Structure of a Transformation.

When you define an output of type CSV, there are a few optional parameters you can add to the output directive to customize how the data is parsed:

All of these parameters are optional. A CSV output directive might for example look like this:

In the Transform Message component, you can define a CSV type through the following methods:

An excel workbook is a sequence of sheets, in DataWeave this is mapped to an object where each sheet is a key. Only one table is allowed per excel sheet. A table is expressed as an array of rows. A row is an object where its keys are the columns and the values the cell content.

For example:

When you define an input of type excel, there are a few optional parameters you can add in the XML definition of your Mule project to customize how the data is parsed.

These properties can be either set via the XML of your Mule project:

Or via the UI of the Transform Message component:

See To Define Input and Output Structure of a Transformation.

When you define an output of type excel, there are a few optional parameters you can add to the output directive to customize how the data is parsed:

All of these parameters are optional. An excel output directive might for example look like this:

In the Transform Message component, you can define a excel type through the following methods:

The XML data-structure is mapped to DataWeave objects that may contain other objects as values to their keys. Repeated keys are supported. For example:

When you define an input of type XML, there are a few optional parameters you can add in the XML definition of your Mule project to customize how the data is parsed.

These properties can be either set via the XML of your Mule project:

Or via the UI of the Transform Message component:

See To Define Input and Output Structure of a Transformation.

When you define an output of type XML, there are a few optional parameters you can add to the output directive to customize how the data is parsed:

The inlineCloseOn parameter defines if the output is structured like this (by default):

or like this (set with a value of "empty"):

In the Transform Message component, you can define a XML type through the following methods:

JSON data-structures are mapped to DataWeave data-structures in a straight forward way as they share a lot of similarities.

When you define an output of type JSON, there are a few optional parameters you can add to the output directive to customize how the data is parsed:

In the Transform Message component, you can define a JSON type through the following methods:

When you define an input of type Flat File, there are a few optional parameters you can add in the XML definition of your Mule project to customize how the data is parsed.

Flat file reader properties are the same as the COBOL copybook reader properties. See Reader Properties (for Copybook).

These properties can be set through the XML of your Mule project:

Alternatively, you can set them through the UI of the Transform Message component.

See To Define Input and Output Structure of a Transformation.

When you define an output of type Flat File there are a few optional parameters you can add to the output directive to customize how the data is written:

Flat file writer properties are the same as the COBOL copybook writer properties. See Writer Properties (for Copybook).

In the Transform Message component, you can define a Flat File type through the following methods:

When you define an input of type Fixed Width, there are a few optional parameters you can add in the XML definition of your Mule project to customize how the data is parsed.

Fixed Width reader properties are the same as the COBOL copybook reader properties. See Reader Properties (for Copybook).

These properties can be either set via the XML of your Mule project:

Or via the UI of the Transform Message component

See To Define Input and Output Structure of a Transformation.

When you define an output of type Fixed Width, there are a few optional parameters you can add to the output directive to customize how the data is written:

Fixed Width writer properties are the same as the COBOL copybook writer properties. See Writer Properties (for Copybook).

In the Transform Message component, you can define a Fixed Width type through the following methods:

When you import a Copybook definition, the Transform Message component converts the definition to a flat file schema that you can reference with schemaPath property.

To import a copybook definition:

For example, assume that you have a copybook definition file (mailing-record.cpy) that looks like this:

When you import the schema, the Transform component converts the copybook file to a flat file schema that it stores in the src/main/resources/schema folder of your Mule project. In flat file format, the copybook definition above looks like this:

After importing the copybook, you can use the schemaPath property to reference the associated flat file through the output directive. For example: output application/flatfile schemaPath="src/main/resources/schemas/mailing-record.ffd"

Not all copybook features are supported by the COBOL Copybook format in DataWeave. In general, the format supports most common usages and simple patterns, including:

Unsupported features include:

Mule 3 support: Version 3.9.3 and later

REDEFINES facilitates dynamic interpretation of data in a record. When you import a copybook with REDEFINES present, the generated schema uses a special grouping with the name '*' (or '*1', '*2', and so on, if multiple REDEFINES groupings are present at the same level) to combine all the different interpretations. You use this special grouping name in your DataWeave expressions just as you use any other grouping name.

Use of REDEFINES groupings has higher overhead than normal copybook groupings, so MuleSoft recommends that you remove REDEFINES from your copybooks where possible before you import them into Studio.

BINARY (COMP), COMP-5 (Mule 3 support: Version 3.9.3 and later), or PACKED-DECIMAL (COMP-3) usages are only supported with single-byte character encodings, which use the entire range of 256 potential character codes. UTF-8 and other variable-length encodings are not supported for these usages (because they’re not single-byte), and ASCII is also not supported (because it doesn’t use the entire range). Supported character encodings include ISO-8859-1 (an extension of ASCII to full 8 bits) and other 8859 variations and EBCDIC (IBM037).

REDEFINES (Mule 3 support: Version 3.9.3 and later) requires you to use a single-byte-per-character character encoding for the data, but any single-byte-per-character encoding can be used unless BINARY (COMP), COMP-5, or PACKED-DECIMAL (COMP-3) usages are included in the data.

The most common issue with copybook imports is a failure to follow the COBOL standard for input line regions. The copybook import parsing ignores the contents of columns 1-6 of each line, and ignores all lines with an '*' (asterisk) in column 7. It also ignores everything beyond column 72 in each line. This means that all your actual data definitions need to be within columns 8 through 72 of input lines.

Tabs in the input are not expanded because there is no defined standard for tab positions. Each tab character is treated as a single space character when counting copybook input columns.

Indentation is ignored when processing the copybook, with only level-numbers treated as significant. This is not normally a problem, but it means that copybooks might be accepted for import even though they are not accepted by COBOL compilers.

Both warnings and errors might be reported as a result of a copybook import. Warnings generally tell of unsupported or unrecognized features, which might or might not be significant. Errors are notifications of a problem that means the generated schema (if any) will not be a completely accurate representation of the copybook. You should review any warnings or errors reported and decide on the appropriate handling, which might be simply accepting the schema as generated, modifying the input copybook, or modifying the generated schema.

When you define an input of type Copybook, there are a few optional parameters you can add in the XML definition of your Mule project to customize how the data is parsed.

Note that schemas with type Binary or Packed don’t allow for line break detection, so setting recordParsing to lenient only allows long records to be handled, not short ones. These schemas only work with certain single-byte character encodings (so not with UTF-8 or any multibyte format).

These properties can be either set via the XML of your Mule project:

Or via the UI of the Transform Message component

See To Define Input and Output Structure of a Transformation.

When you define an output of type copybook, you can customize the way data is written by adding optional parameters to the output directive:

In the Transform Message component, you can define a Fixed Width type through the following methods: