Contents
The TIBCO StreamBase® File Reader reads a text file and emits a tuple with a string field containing the entire contents of the file.
The adapter can be configured to read a file at start-up or in response to the receipt of a tuple on its control input port.
The adapter has a sample, described in File Reader Input Adapter Sample.
This section describes the properties you can set for this adapter, using the various tabs of the Properties view in StreamBase Studio.
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.
Property | Data Type | Default | Description | StreamSQL Property |
---|---|---|---|---|
Default File Name | String | None | The default file name if no name is provided on the control input port. Choose file by selecting from list box or by browsing. | DefaultFileName |
Read Default File at Startup | check box | Unselected | If enabled, the default file is read at startup. | ReadDefaultFileAtStartup |
Use Default Charset | check box | Selected | If selected, specifies whether the Java platform default character set is to be used. If cleared, a valid character set name must be specified for the Character Set property. | UseDefaultCharset |
Character Set | string | None | The name of the character set encoding that the adapter is to use to read input or write output. | Charset |
Enable Control Port | check box | Selected | If enabled, a control input port is present for enqueuing tuples with the names of files to read. | EnableControlPort |
Enable Status Port | check box | Selected | If enabled, a status output port is present on which tuples are emitted to convey to important events within the adapter. | EnableStatusPort |
Read As Binary Data | check box | Unselected | If enabled the adapter will read the file as binary data into a single tuple with a blob field. | BlobData |
One Tuple Per Line | check box | Unselected | If enabled, a tuple is emitted for each line read from the file. If disabled, the entire file contents is emitted in a single tuple. | OneTuplePerLine |
Preserve New Lines | check box | Unselected | If enabled, new lines read from the input file are preserved. | PreserveNewLines |
Line Separator | String | None | If not preserving new lines from the input file, new lines are replaced with this string. | LineSeparator |
Pass Through Fields | check box | Unselected | If enabled, the incoming tuples fields will be duplicated to the outgoing tuple. If enabled you must specify which input field provides the incoming file name. | PassThroughFields |
Filename Field | String | None | Determines which field of the incoming tuple will be used as the filename to process. Used when Pass Through Fields is checked. | FilenameField |
File Contents Field Name | String | FileContents | The name of the field in the outgoing tuple that holds the file contents. May only be used when Pass Through Fields is selected. | FileContentsFieldName |
Replacement Data Field Name | String | None | The name of the field in the incoming tuple that will supply the data for any parameter replacements in the file being read. Can only be used when Pass Through Fields is selected. See the Replacement Fields section below for further details. | ReplacementDataFieldName |
Read Files Synchronously | check box | Unselected | If enabled the file will be read synchronously without the use of a thread. | ReadFilesSynchronously |
Log Level | drop-down list | INFO | Controls the level of verbosity the adapter uses to send notifications to the console. This setting can be higher than the containing application's log level. If set lower, the system log level will be used. Available values, in increasing order of verbosity, are: OFF, ERROR, WARN, INFO, DEBUG, TRACE, and ALL. | LogLevel |
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.
Caution
Concurrency settings are not suitable for every application, and using these settings requires a thorough analysis of your application. For details, see Execution Order and Concurrency, which includes important guidelines for using the concurrency options.
Replacement fields are tokens in input files that take the form of StreamBase
parameters, such as ${param-name}
. The adapter replaces
each such token at run time with data from its input tuple. When the adapter reads
the file, it matches each token to a subfield of the same name from the input
stream's tuple, and the value of that field is substituted for the token. All tokens
are similarly processed before sending output.
All tokens must match the name of some field
in the input tuple for the adapter to generate output. If any token does not match,
StreamBase Server throws a StreamBase Exception: Unable to
access a field from the replacement tuple while while trying to parse item
<token>
.
Although the tokens take the form of StreamBase module parameters, they are scoped to the adapter instance, which has no capability to substitute StreamBase parameter values for tokens.
A token can access an array by indexing into it using the standard [0]
bracket notation, such as ${ListField[0].SubField}
.
Tokens can format field values by including standard Java format strings within
braces, inserted at the end of the parameter definition. An example for an integer
would be ${IntField{%05d}}
. Formatting is supported for
all data types except for string and boolean fields. Use the standard java.text.SimpleDateFormat
class
rules for formatting timestamps.
The following table illustrates how tokens can format field values.
Data Type | Token and Formatting Examples |
---|---|
String |
${StringField}
|
Boolean |
${BooleanField}
|
Int |
${IntField} or formatted ${IntField{%05d}}
|
Long |
${LongField} or formatted ${LongField{%05d}}
|
Double |
${DoubleField} or formatted ${DoubleField{%+10.4f}}
|
Timestamp |
${TimeField} or formatted ${TimeField{dd-MMM-yyyy hh:mm:ss}}
|
List |
${ListField[0]} or lists in lists ${NestedListListField[0][0].Field}
|
Tuple |
${TupleField}
|
Tuple, JSON-formatted |
${TupleField{JSON}}
|
Tuple, JSON, including null fields |
${TupleField{JSON|INCLUDE_NULL_FIELDS}}
|
Tuple, JSON, formatted as list |
${TupleField{JSON|PREFER_LIST}}
|
Tuple, JSON, formatted as map |
${TupleField{JSON|PREFER_MAP}}
|
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.
The File Reader adapter's ports are used as follows:
-
Control (input): Tuples enqueued on this port cause the adapter to read a text file. The schema for this port has the following field:
-
FileName, string. The name of the file to read. If null, the file name is taken from the adapter's Default File Name property.
Note
If
Pass Through Fields
is selected, then this schema can be anything, but you must specify the Filename Field. -
-
Status (output): The adapter emits tuples from this port when significant events occur, such as when an attempt to read a file fails. The schema for this port has the following fields:
-
Type, string. Returns one of the following values to convey the type of event:
-
User Input
-
Read
-
-
Action, string. Returns an action associated with the event type:
-
Rejected
-
Error
-
Starting
-
Finished
-
-
Object, string. Returns an event type-specific value, such as the name of the file which a read failed or the control input tuple that was rejected.
-
Message, string. Returns a human-readable description of the event.
-
-
Data (output): Tuples are emitted on this port when files are successfully read. The schema for this port contains the following fields:
Note
If
Pass Through Fields
is selected, then this schema instead matches your incoming schema with an additional field with the name specified in theFile Contents Field Name
parameter.-
FileName, string. The name of the file that was read.
-
FileContents, string. The contents of the file.
-
The File Reader adapter uses typecheck messages to help you configure the adapter within your StreamBase application. In particular, the adapter generates typecheck messages for the following reasons:
-
The Control Input Port does not have exactly one field, of type string, to receive the name of the file to read.
-
The Default File Name property contains the name of an invalid file.
The adapter generates warning messages during runtime under various conditions, including:
-
A control tuple is received with a null value in its FileName field and a value for the adapter's Default File Name property has not been specified.
-
An error occurs attempting to read a file.
When suspended, the adapter stops processing requests to read files.
When resumed, the adapter once again starts processing requests to read files.