org.apache.kafka.streams.kstream.Windows Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.kafka.streams.kstream;
import org.apache.kafka.streams.processor.TimestampExtractor;
import org.apache.kafka.streams.state.WindowBytesStoreSupplier;
import java.time.Duration;
import java.util.Map;
import static org.apache.kafka.streams.kstream.internals.WindowingDefaults.DEFAULT_RETENTION_MS;
/**
* The window specification for fixed size windows that is used to define window boundaries and grace period.
*
* 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 late and will not be processed but are dropped.
*
* Warning: It may be unsafe to use objects of this class in set- or map-like collections,
* since the equals and hashCode methods depend on mutable fields.
*
* @param type of the window instance
* @see TimeWindows
* @see UnlimitedWindows
* @see JoinWindows
* @see SessionWindows
* @see TimestampExtractor
*/
public abstract class Windows {
private long maintainDurationMs = DEFAULT_RETENTION_MS;
@Deprecated public int segments = 3;
protected Windows() {}
@Deprecated // remove this constructor when we remove segments.
Windows(final int segments) {
this.segments = segments;
}
/**
* Set the window maintain duration (retention time) in milliseconds.
* This retention time is a guaranteed lower bound for how long a window will be maintained.
*
* @param durationMs the window retention time in milliseconds
* @return itself
* @throws IllegalArgumentException if {@code durationMs} is negative
* @deprecated since 2.1. Use {@link Materialized#withRetention(Duration)}
* or directly configure the retention in a store supplier and use {@link Materialized#as(WindowBytesStoreSupplier)}.
*/
@Deprecated
public Windows until(final long durationMs) throws IllegalArgumentException {
if (durationMs < 0) {
throw new IllegalArgumentException("Window retention time (durationMs) cannot be negative.");
}
maintainDurationMs = durationMs;
return this;
}
/**
* Return the window maintain duration (retention time) in milliseconds.
*
* @return the window maintain duration
* @deprecated since 2.1. Use {@link Materialized#retention} instead.
*/
@Deprecated
public long maintainMs() {
return maintainDurationMs;
}
/**
* Set the number of segments to be used for rolling the window store.
* This function is not exposed to users but can be called by developers that extend this class.
*
* @param segments the number of segments to be used
* @return itself
* @throws IllegalArgumentException if specified segments is small than 2
* @deprecated since 2.1 Override segmentInterval() instead.
*/
@Deprecated
protected Windows segments(final int segments) throws IllegalArgumentException {
if (segments < 2) {
throw new IllegalArgumentException("Number of segments must be at least 2.");
}
this.segments = segments;
return this;
}
/**
* Create all 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
*/
public abstract Map windowsFor(final long timestamp);
/**
* Return the size of the specified windows in milliseconds.
*
* @return the size of the specified windows
*/
public abstract long size();
/**
* 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).
*/
public abstract long gracePeriodMs();
}