com.devexperts.qd.util

Class RecordProcessor

java.lang.Object

com.devexperts.qd.util.RecordProcessor

Direct Known Subclasses:

DataProcessor

public abstract class RecordProcessor
extends Object

This class is base class for listening for records availability and rescheduling their processing using Executor. Classes that extend RecordProcessor listen for incoming records and process them in separate thread or threads. Executor may be single thread or thread pool executor. One Executor may be shared by different record processors. It is guaranteed that new processing handler will not be called until previous has completed its work. RecordProcessor registers RecordListener in RecordProvider when startProcessing(RecordProvider) startProcessing} method is called. Class client is responsible to call stopProcessing when processing is not required any more. This class is thread-safe and lock-free. Change carefully.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	RecordProcessor(Executor executor) Constructs new record processor for the specified executor.

Method Summary

Modifier and Type	Method and Description
boolean	hasMoreToProcess() Returns true when this RecordProcessor has more records available to process or its task is scheduled for processing.
protected abstract void	process(RecordSource source) Method for processing incoming records.
protected void	signalNoMoreToProcess() This method is called immediately before hasMoreToProcess() becomes false.
void	startProcessing(RecordProvider provider) Starts processing for the specified RecordProvider.
void	stopProcessing() Stops processing.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

RecordProcessor

protected RecordProcessor(Executor executor)

Constructs new record processor for the specified executor.

Throws:

NullPointerException - if executor is null.

Method Detail

process

protected abstract void process(RecordSource source)

Method for processing incoming records. When record is received, RecordProcessor calls this method in Executor thread.

startProcessing

public void startProcessing(RecordProvider provider)

Starts processing for the specified RecordProvider. This method may be called at most once after construction.

Throws:

NullPointerException - if provider is null.

IllegalStateException - if called multiple times. It is checked weakly to ensure fail-fast error detection behaviour. There is no strict thread-safe guarantee for this exception to be thrown if this method is called concurrently from multiple threads.

stopProcessing

public void stopProcessing()

Stops processing. Unregisters RecordListener on RecordProvider. This method may be called only after startProcessing(RecordProvider). Note: client code is responsible for disposing RecordProvider originally passed to RecordProcessor.

Throws:

IllegalStateException - if called before startProcessing(RecordProvider).

hasMoreToProcess

public boolean hasMoreToProcess()

Returns true when this RecordProcessor has more records available to process or its task is scheduled for processing.

signalNoMoreToProcess

protected void signalNoMoreToProcess()

This method is called immediately before hasMoreToProcess() becomes false.