Input and output adapters to Esper provide the means of accepting events from various sources, and for making available events to destinations.
The following input adapters exist. There are currently no output adapters available.
Table 1.1. Input and Output Adapters
Adapter | Description |
---|---|
CSV Input Adapter | The CSV input adapter can read one or more CSV-formatted input sources, transform the textual values into events, and play the events into the engine. The adapter also makes it possible to run complete simulations of events arriving in time-order from different input streams. |
The net.esper.adapter.AdapterInputSource encapsulates information about an input source. Input adapters use the AdapterInputSource to determine how to read input. The class provides constructors for use with different input sources:
java.io.Reader to read character streams
java.io.InputStream to read byte streams
java.net.URL
Classpath resource by name
java.io.File
Adapters resolve Classpath resources in the following order:
Current thread classloader via Thread.currentThread().getContextClassLoader().getResourceAsStream
If the resource is not found: AdapterInputSource.class.getResourceAsStream
If the resource is not found: AdapterInputSource.class.getClassLoader().getResourceAsStream
The InputAdapter interface allows client applications to control the state of an input adapter. It provides state transition methods that each input adapter implements.
An input adapter is always in one of the following states:
Opened - The begin state; The adapter is not generating events in this state
Started - When the adapter is active and generating events
Paused - When operation of the adapter is suspended
Destroyed
The state transition table below outlines input adapter states and, for each state, the valid state transitions: