tHMapFile properties for Apache Spark Batch - 6.5

Storage

To connect to an HDFS installation, select the Define a storage configuration component check box and then select the name of the component to use from those available in the drop-down list.

This option requires you to have previously configured the connection to the HDFS installation to be used, as described in the documentation for the tHDFSConfiguration component.

If you leave the Define a storage configuration component check box unselected, you can only convert files locally.

Configure Component

To configure the component, click the [...] button and, in the [Component Configuration] window, perform the following actions.

1. Click the Select button next to the Record Map field and then, in the [Select a Map] dialog box that opens, select the map you want to use and then click OK.

   This map must have been previously created in Talend Data Mapper .

   Note that the input and output representations are those defined in the map, and cannot be changed in the component.

2. Click Next.

3. Tell the component where each new record begins. In order for you to be able to do so, you need to fully understand the structure of your data.

   Exactly how you do this varies depending on the input representation being used, and you will be presented with one of the following options.

   1. Select an appropriate record delimiter for your data. Note that you must specify this value without quotes.

      • Separator lets you specify a separator indicator, such as \n, to identify a new line.

        Supported indicators are \n for a Unix-type new line, \r\n for Windows and \r for Mac, and \t for tab characters.

      • Start/End with lets you specify the initial characters that indicate a new record, such as <root, or the characters that indicate where a record ends. This can also be a regular expression.

        Start with also supports new lines, \n for a Unix-type new line, \r\n for Windows and \r for Mac, and \t for tab characters.

      • Sample File: To test the signature with a sample file, click the [...] button, browse to the file you want to use as a sample, click Open, and then click Run to test your sample.

        Testing the signature lets you check that the total number of records and their minimum and maximum length corresponds to what you expect based on your knowledge of the data. This step assumes you have a local subset of your data to use as a sample.

      • Click Finish.

   2. If your input representation is COBOL or Flat with positional and/or binary encoding properties, define the signature for the input record structure:

      • Input Record root corresponds to the root element in your input record.

      • Minimum Record Size corresponds to the size in bytes of the smallest record. If you set this value too low, you may encounter performance issues, since the component will perform more checks than necessary when looking for a new record.

      • Maximum Record Size corresponds to the size in bytes of the largest record, and is used to determine how much memory is allocated to read the input.

      • Sample from Workspace or Sample from File System: To test the signature with a sample file, click the [...] button, and then browse to the file you want to use as a sample.

        Testing the signature lets you check that the total number of records and their minimum and maximum length corresponds to what you expect based on your knowledge of the data. This step assumes you have a local subset of your data to use as a sample.

      • Footer Size corresponds to the size in bytes of the footer, if any. At runtime, the footer will be ignored rather than being mistakenly included in the last record. Leave this field empty if there is no footer.

      • Click the Next button to open the [Signature Parameters] window, select the fields that define the signature of your record input structure (that is, to identify where a new record begins), update the Operation and Value columns as appropriate, and then click Next.

      • In the [Record Signature Test] window that opens, check that your Records are correctly delineated by scrolling through them with the Back and Next buttons and performing a visual check, and then click Finish.

Input

Click the [...] button to define the path to where the input file is stored.

Output

Click the [...] button to define the path to where the output files will be stored.

Action

Open Map Editor

Click the [...] button to open the map for editing in the Map Editor of Talend Data Mapper .

For more information, see Talend Data Mapper User Guide.

Usage rule

This component is used with a tHDFSConfiguration component which defines the connection to the HDFS storage, or as a standalone component for mapping local files only.