Package org.apache.iotdb.pipe.api

Interface PipeSource

All Superinterfaces:

AutoCloseable, PipeExtractor, PipePlugin

public interface PipeSource
extends PipeExtractor

PipeSource

PipeSource is responsible for capturing Events from sources.

Various data sources can be supported by implementing different PipeSource classes.

The lifecycle of a PipeSource is as follows:

• When a collaboration task is created, the KV pairs of `WITH EXTRACTOR` clause in SQL are parsed and the validation method validate(PipeParameterValidator) will be called to validate the PipeParameters.
• Before the collaboration task starts, the method customize(PipeParameters, PipeSourceRuntimeConfiguration) will be called to configure the runtime behavior of the PipeSource.
• Then the method start() will be called to start the PipeSource.
• While the collaboration task is in progress, the method supply() will be called to capture Events from sources and then the Events will be passed to the PipeProcessor.
• The method AutoCloseable.close() will be called when the collaboration task is cancelled (the `DROP PIPE` command is executed).

Method Summary

Modifier and Type	Method	Description
void	customize(PipeParameters parameters, PipeSourceRuntimeConfiguration configuration)	This method is mainly used to customize PipeSource.
void	start()	Start the PipeSource.
Event	supply()	Supply single Event from the PipeSource and the caller will send the Event to the PipeProcessor.
void	validate(PipeParameterValidator validator)	This method is mainly used to validate PipeParameters and it is executed before customize(PipeParameters, PipeSourceRuntimeConfiguration) is called.

Methods inherited from interface java.lang.AutoCloseable

close

Methods inherited from interface org.apache.iotdb.pipe.api.PipeExtractor

customize

Method Details

validate

void validate(PipeParameterValidator validator)
       throws Exception

This method is mainly used to validate PipeParameters and it is executed before customize(PipeParameters, PipeSourceRuntimeConfiguration) is called.

Specified by:

validate in interface PipeExtractor

Parameters:

validator - the validator used to validate PipeParameters

Throws:

Exception - if any PipeParameters is invalid

customize

void customize(PipeParameters parameters,
 PipeSourceRuntimeConfiguration configuration)
        throws Exception

This method is mainly used to customize PipeSource. In this method, the user can do the following things:

• Use PipeParameters to parse key-value pair attributes entered by the user.
• Set the running configurations in PipeSourceRuntimeConfiguration.

This method is called after the method validate(PipeParameterValidator) is called.

Parameters:

parameters - used to parse the input PipeParameters entered by the user

configuration - used to set the required properties of the running PipeSource

Throws:

Exception - the user can throw errors if necessary

start

void start()
    throws Exception

Start the PipeSource. After this method is called, Events should be ready to be supplied by supply(). This method is called after customize(PipeParameters, PipeSourceRuntimeConfiguration) is called.

Specified by:

start in interface PipeExtractor

Throws:

Exception - the user can throw errors if necessary

supply

Event supply()
      throws Exception

Supply single Event from the PipeSource and the caller will send the Event to the PipeProcessor. This method is called after start() is called.

Specified by:

supply in interface PipeExtractor

Returns:

the Event to be supplied. the Event may be null if the PipeSource has no more Events at the moment, but the PipeSource is still running for more Events.

Throws:

Exception - the user can throw errors if necessary