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public interface Suppressed<K> { /** * Marker interface for a buffer configuration that is "strict" in the sense that it will strictly * enforce the time bound and never emit early. */ interface StrictBufferConfig extends BufferConfig<StrictBufferConfig> {} interface BufferConfig<BC extends BufferConfig<BC>> { /** * Create a size-constrained buffer in terms of the maximum number of keys it will store. */ static BufferConfig<?> maxRecords(final long recordLimit); /** * Set a size constraint on the buffer in terms of the maximum number of keys it will store. */ BC withMaxRecords(final long recordLimit); /** * Create a size-constrained buffer in terms of the maximum number of bytes it will use. */ static BufferConfig<?> maxBytes(final long byteLimit); /** * Set a size constraint on the buffer, the maximum number of bytes it will use. */ BC withMaxBytes(final long byteLimit); /** * Create a buffer unconstrained by size (either keys or bytes). * * As a result, the buffer will consume as much memory as it needs, dictated by the time bound. * * If there isn't enough heap available to meet the demand, the application will encounter an * {@link OutOfMemoryError} and shut down (not guaranteed to be a graceful exit). Also, note that * JVM processes under extreme memory pressure may exhibit poor GC behavior. * * This is a convenient option if you doubt that your buffer will be that large, but also don't * wish to pick particular constraints, such as in testing. * * This buffer is "strict" in the sense that it will enforce the time bound or crash. * It will never emit early. */ static StrictBufferConfig unbounded(); /** * Set the buffer to be unconstrained by size (either keys or bytes). * * As a result, the buffer will consume as much memory as it needs, dictated by the time bound. * * If there isn't enough heap available to meet the demand, the application will encounter an * {@link OutOfMemoryError} and shut down (not guaranteed to be a graceful exit). Also, note that * JVM processes under extreme memory pressure may exhibit poor GC behavior. * * This is a convenient option if you doubt that your buffer will be that large, but also don't * wish to pick particular constraints, such as in testing. * * This buffer is "strict" in the sense that it will enforce the time bound or crash. * It will never emit early. */ StrictBufferConfig withNoBound(); /** * Set the buffer to gracefully shut down the application when any of its constraints are violated * * This buffer is "strict" in the sense that it will enforce the time bound or shut down. * It will never emit early. */ StrictBufferConfig shutDownWhenFull(); /** * Sets the buffer to use on-disk storage if it requires more memory than the constraints allow. * * This buffer is "strict" in the sense that it will never emit early. */ StrictBufferConfig spillToDiskWhenFull(); /** * Set the buffer to just emit the oldest records when any of its constraints are violated. * * This buffer is "not strict" in the sense that it may emit early, so it is suitable for reducing * duplicate results downstream, but does not promise to eliminate them. */ BufferConfig emitEarlyWhenFull(); } /** * Configure the suppression to emit only the "final results" from the window. * * By default all Streams operators emit results whenever new results are available. * This includes windowed operations. * * This configuration will instead emit just one result per key for each window, guaranteeing * to deliver only the final result. This option is suitable for use cases in which the business logic * requires a hard guarantee that only the final result is propagated. For example, sending alerts. * * To accomplish this, the operator will buffer events from the window until the window close (that is, * until the end-time passes, and additionally until the grace period expires). Since windowed operators * are required to reject late events for a window whose grace period is expired, there is an additional * guarantee that the final results emitted from this suppression are eventually consistent with the upstream * operator and its queriable state, if enabled. * * @param bufferConfig A configuration specifying how much space to use for buffering intermediate results. * This is required to be a "strict" config, since it would violate the "final results" * property to emit early and then issue an update later. * @param <K> The key type for the KTable to apply this suppression to. "Final results" mode is only available * on Windowed KTables (this is enforced by the type parameter). * @return a "final results" mode suppression configuration */ static <K extends Windowed> Suppressed<K> untilWindowCloses(final StrictBufferConfig bufferConfig); /** * Configure the suppression to wait {@code timeToWaitForMoreEvents} amount of time after receiving a record * before emitting it further downstream. If another record for the same key arrives in the mean time, it replaces * the first record in the buffer but does <em>not</em> re-start the timer. * * @param timeToWaitForMoreEvents The amount of time to wait, per record, for new events. * @param <K> The key type for the KTable to apply this suppression to. * @return a suppression configuration */ static <K> Suppressed<K> untilTimeLimit(final Duration timeToWaitForMoreEvents); /** * Configure the suppression to wait {@code timeToWaitForMoreEvents} amount of time after receiving a record * before emitting it further downstream. If another record for the same key arrives in the mean time, it replaces * the first record in the buffer but does <em>not</em> re-start the timer. * * @param timeToWaitForMoreEvents The amount of time to wait, per record, for new eventsbufferConfig A configuration specifying how much space to use for buffering intermediate results. * @param <K> The key type for the KTable to apply this suppression to. * @return a suppression configuration */ static <K> Suppressed<K> untilTimeLimit(final Duration timeToWaitForMoreEvents, final BufferConfig bufferConfig); } |
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