...
- Add new interface to take the place of Windows: EnumerableWindowDefinition
- Add "implements EnumerableWindowDefinition" to TimeWindows and UnlimitedWindows
- Do not add the new interface to JoinWindows, which should not be part of this hierarchy. It will naturally become disconnected when we remove Windows
- Add "implements EnumerableWindowDefinition" to Windows and deprecate it.
...
- Swap out the argument type in both windowBy methods
New interface to take the place of Windows: EnumerableWindowDefinition
| Code Block |
|---|
| language | java |
|---|
| title | FixedSizeWindowDefinition |
|---|
| linenumbers | true |
|---|
|
/**
* The window specification for windows that can be enumerated for a single event based on its time.
* <p>
* Grace period defines how long to wait on out-of-order events. That is, windows will continue to accept new records until {@code stream_time >= window_end + grace_period}.
* Records that arrive after the grace period passed are considered <em>late</em> and will not be processed but are dropped.
* <p>
* Window state is stored until it is no longer needed, measured from the beginning of the window. To assist the store in not discarding window state too soon, this definition
* also includes a {@code maxSize()}, indicating the longest span windows can have between their start and end. This does not need to include the grace period.
*
* @param <W> type of the window instance
*/
public interface EnumerableWindowDefinition<W extends Window> {
/**
* List all possible windows that contain the provided timestamp,
* indexed by non-negative window start timestamps.
*
* @param timestamp the timestamp window should get created for
* @return a map of {@code windowStartTimestamp -> Window} entries
*/
Map<Long, W> windowsFor(final long timestamp);
/**
* Return an upper bound on the size of windows in milliseconds.
* Used to determine the lower bound on store retention time.
*
* @return the maximum size of the specified windows
*/
long maxSize();
/**
* Return the window grace period (the time to admit
* out-of-order events after the end of the window.)
*
* Delay is defined as (stream_time - record_timestamp).
*/
long gracePeriodMs();
} |
...
| Code Block |
|---|
| language | java |
|---|
| title | deprecation |
|---|
|
/**
* ... the javadoc doesn't change
*
* @deprecated since 2.7 Implement EnumerableWindowDefinition instead.
*/
@Deprecated
public abstract class Windows<W extends Window> implements EnumerableWindowDefinition<W> {
// ... nothing else changes
} |
Swap out the argument type in windowBy
Note, because Windows now implements EnumerableWindowDefinition, all existing implementations of Windows will automatically work with this change, so there is no compatibility concern.
| Code Block |
|---|
|
public interface CogroupedKStream<K, VOut> {
...
- <W extends Window> TimeWindowedCogroupedKStream<K, VOut> windowedBy(final Windows<W> windows);
+ <W extends Window> TimeWindowedCogroupedKStream<K, VOut> windowedBy(final EnumerableWindowDefinition<W> windows);
...
} |
| Code Block |
|---|
|
public interface KGroupedStream<K, V> {
...
- <W extends Window> TimeWindowedKStream<K, V> windowedBy(final Windows<W> windows);
+ <W extends Window> TimeWindowedKStream<K, V> windowedBy(final EnumerableWindowDefinition<W> windows);
...
} |
Compatibility, Deprecation, and Migration Plan
Windows is deprecated. Otherwise, no compatibility issues arise. We can remove Windows cleanly later on.
Rejected AlternativesAlternatives
None None (yet)