com.espertech.esper.client
Interface EPIterable

All Known Subinterfaces:

EPStatement, EPStatementSPI

All Known Implementing Classes:

EPStatementImpl

public interface EPIterable

Interface to iterate over events.

Method Summary

EventType	getEventType() Returns the type of events the iterable returns.
java.util.Iterator<EventBean>	iterator() Returns a concurrency-unsafe iterator over events representing statement results (pull API).
SafeIterator<EventBean>	safeIterator() Returns a concurrency-safe iterator that iterates over events representing statement results (pull API) in the face of concurrent event processing by further threads.

Method Detail

iterator

java.util.Iterator<EventBean> iterator()

Returns a concurrency-unsafe iterator over events representing statement results (pull API).

The iterator is useful for applications that are single-threaded, or that coordinate the iterating thread with event processing threads that use the sendEvent method using application code locks or synchronization.

The iterator returned by this method does not make any guarantees towards correctness of results and fail-behavior, if your application processes events into the engine instance using the sendEvent method by multiple threads.

Use the safeIterator method for concurrency-safe iteration. Note the safe iterator requires applications to explicitly close the safe iterator when done iterating.

Returns:

event iterator

safeIterator

SafeIterator<EventBean> safeIterator()

Returns a concurrency-safe iterator that iterates over events representing statement results (pull API) in the face of concurrent event processing by further threads.

In comparison to the regular iterator, the safe iterator guarantees correct results even as events are being processed by other threads. The cost is that the iterator holds one or more locks that must be released via the close method. Any locks are acquired at the time this method is called.

This method is a blocking method. It may block until statement processing locks are released such that the safe iterator can acquire any required locks.

An application MUST explicitly close the safe iterator instance using the close method, to release locks held by the iterator. The call to the close method should be done in a finally block to make sure the iterator gets closed.

Multiple safe iterators may be not be used at the same time by different application threads. A single application thread may hold and use multiple safe iterators however this is discouraged.

Returns:

safe iterator; NOTE: Must use the close method to close the safe iterator, preferably in a finally block

getEventType

EventType getEventType()

Returns the type of events the iterable returns.

Returns:

event type of events the iterator returns