/*
* 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.common.annotation.InterfaceStability;
import org.apache.kafka.streams.kstream.internals.UnlimitedWindow;
import org.apache.kafka.streams.processor.TimestampExtractor;
import java.util.HashMap;
import java.util.Map;
/**
* The unlimited window specifications used for aggregations.
* <p>
* An unlimited time window is also called landmark window.
* It has a fixed starting point while its window end is defined as infinite.
* With this regard, it is a fixed-size window with infinite window size.
* <p>
* For time semantics, see {@link TimestampExtractor}.
*
* @see TimeWindows
* @see SessionWindows
* @see JoinWindows
* @see KGroupedStream#count(Windows, String)
* @see KGroupedStream#count(Windows, org.apache.kafka.streams.processor.StateStoreSupplier)
* @see KGroupedStream#reduce(Reducer, Windows, String)
* @see KGroupedStream#reduce(Reducer, Windows, org.apache.kafka.streams.processor.StateStoreSupplier)
* @see KGroupedStream#aggregate(Initializer, Aggregator, Windows, org.apache.kafka.common.serialization.Serde, String)
* @see KGroupedStream#aggregate(Initializer, Aggregator, Windows, org.apache.kafka.streams.processor.StateStoreSupplier)
* @see TimestampExtractor
*/
@InterfaceStability.Unstable
public final class UnlimitedWindows extends Windows<UnlimitedWindow> {
private static final long DEFAULT_START_TIMESTAMP_MS = 0L;
/** The start timestamp of the window. */
public final long startMs;
private UnlimitedWindows(final long startMs) {
this.startMs = startMs;
}
/**
* Return an unlimited window starting at timestamp zero.
*/
public static UnlimitedWindows of() {
return new UnlimitedWindows(DEFAULT_START_TIMESTAMP_MS);
}
/**
* Return a new unlimited window for the specified start timestamp.
*
* @param startMs the window start time
* @return a new unlimited window that starts at {@code startMs}
* @throws IllegalArgumentException if the start time is negative
*/
public UnlimitedWindows startOn(final long startMs) throws IllegalArgumentException {
if (startMs < 0) {
throw new IllegalArgumentException("Window start time (startMs) cannot be negative.");
}
return new UnlimitedWindows(startMs);
}
@Override
public Map<Long, UnlimitedWindow> windowsFor(final long timestamp) {
// always return the single unlimited window
// we cannot use Collections.singleMap since it does not support remove()
final Map<Long, UnlimitedWindow> windows = new HashMap<>();
if (timestamp >= startMs) {
windows.put(startMs, new UnlimitedWindow(startMs));
}
return windows;
}
/**
* {@inheritDoc}
* As unlimited windows have conceptually infinite size, this methods just returns {@link Long#MAX_VALUE}.
*
* @return the size of the specified windows which is {@link Long#MAX_VALUE}
*/
@Override
public long size() {
return Long.MAX_VALUE;
}
/**
* Throws an {@link IllegalArgumentException} because the retention time for unlimited windows is always infinite
* and cannot be changed.
*
* @throws IllegalArgumentException on every invocation
*/
@Override
public UnlimitedWindows until(final long durationMs) {
throw new IllegalArgumentException("Window retention time (durationMs) cannot be set for UnlimitedWindows.");
}
/**
* {@inheritDoc}
* The retention time for unlimited windows in infinite and thus represented as {@link Long#MAX_VALUE}.
*
* @return the window retention time that is {@link Long#MAX_VALUE}
*/
@Override
public long maintainMs() {
return Long.MAX_VALUE;
}
@Override
public boolean equals(final Object o) {
if (o == this) {
return true;
}
if (!(o instanceof UnlimitedWindows)) {
return false;
}
final UnlimitedWindows other = (UnlimitedWindows) o;
return startMs == other.startMs;
}
@Override
public int hashCode() {
return (int) (startMs ^ (startMs >>> 32));
}
}