HDFS File Reader Input Adapter

Name: Use this field to specify or change the component's name, which must be unique in the application. The name must contain only alphabetic characters, numbers, and underscores, and no hyphens or other special characters. The first character must be alphabetic or an underscore.

Adapter: A read-only field that shows the formal name of the adapter.

Class: A field that shows the fully qualified class name that implements the functionality of this adapter. Use this class name when loading the adapter in StreamSQL programs with the APPLY JAVA statement. You can right-click this field and select Copy from the context menu to place the full class name in the system clipboard.

Start with application: If this field is set to Yes or to a module parameter that evaluates to true, an instance of this adapter starts as part of the containing StreamBase Server. If this field is set to No or to a module parameter that evaluates to false, the adapter is loaded with the server, but does not start until you send an sbadmin resume command, or until you start the component with StreamBase Manager. With this option set to No or false, the adapter does not start even if the application as a whole is suspended and later resumed. The recommended setting is selected by default.

Enable Error Output Port: Select this check box to add an Error Port to this component. In the EventFlow canvas, the Error Port shows as a red output port, always the last port for the component. See Using Error Ports and Error Streams to learn about Error Ports.

Description: Optionally enter text to briefly describe the component's purpose and function. In the EventFlow canvas, you can see the description by pressing Ctrl while the component's tooltip is displayed.

The schema is used when you select either the Apache Avro or Parquet serialization format. You can click the Generate Schema link on this tab, which will display a dialog to enter the HDFS://, file://, or local file from which to load the schema.

Use the Concurrency tab to specify parallel regions for this instance of this component, or multiplicity options, or both. The Concurrency tab settings are described in Concurrency Options, and dispatch styles are described in Dispatch Styles.

Given an input text file with the following content:

Line 1 has an int replacement field: ${intval1}
Line 2 has a double replacement field: ${doubleval1{%+5.1f}}
Line 3 has a list of doubles replacement field:${listval1{%6.2f}}
Line 4 has a string replacement field: ${stringval1{%12s}}
Line 5 has a JSON tuple replacement field ${tupleval1{JSON}}

a control port input schema like this:

FileName string
replacements (
    stringval1 string,
    doubleval1 double, 
    listval1 list(double), 
    intval1 int,
    tupleval1 (
        tint1 int,
        tts1 timestamp
    )
)

and an input tuple with these values (using a default file name):

FileName    = null,
replacements=(stringval1=StreamBase,
              doubleval1=456.789,
              listval1=[9.81,7.62,5.43],
              intval1=123,
              tupleval1 (
                   tint1=101,
                   tts1=2015-01-15 08:15:20
              )
)

The file reader outputs:

Line 1 has an int replacement field: 123
Line 2 has a double replacement field: +456.8
Line 3 has a list of doubles replacement field:[9.81, 7.62, 5.43]
Line 4 has a string replacement field:   StreamBase
Line 5 has a JSON tuple replacement field {"tint1":101,"tts1":"2015-01-15 08:15:20.000-0500"}

The order of fields in the schema does not have to match the order of tokens in the input file. The same token can appear any number of times. Each instance will receive the same replacement value.