org.apache.beam.sdk.testing.StaticWindows.java Source code

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Here is the source code for org.apache.beam.sdk.testing.StaticWindows.java

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/*
 * 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.beam.sdk.testing;

import static org.apache.beam.vendor.guava.v26_0_jre.com.google.common.base.Preconditions.checkArgument;

import java.util.Collection;
import java.util.Collections;
import java.util.Objects;
import org.apache.beam.sdk.coders.Coder;
import org.apache.beam.sdk.transforms.windowing.BoundedWindow;
import org.apache.beam.sdk.transforms.windowing.IncompatibleWindowException;
import org.apache.beam.sdk.transforms.windowing.NonMergingWindowFn;
import org.apache.beam.sdk.transforms.windowing.WindowFn;
import org.apache.beam.sdk.transforms.windowing.WindowMappingFn;
import org.apache.beam.vendor.guava.v26_0_jre.com.google.common.base.Supplier;
import org.apache.beam.vendor.guava.v26_0_jre.com.google.common.collect.Iterables;
import org.joda.time.Duration;

/**
 * A {@link WindowFn} that assigns all elements to a static collection of {@link BoundedWindow
 * BoundedWindows}. Side inputs windowed into static windows only support main input windows in the
 * provided collection of windows.
 */
final class StaticWindows extends NonMergingWindowFn<Object, BoundedWindow> {
    private final Supplier<Collection<BoundedWindow>> windows;
    private final Coder<BoundedWindow> coder;

    private final boolean onlyExisting;

    private StaticWindows(Supplier<Collection<BoundedWindow>> windows, Coder<BoundedWindow> coder,
            boolean onlyExisting) {
        this.windows = windows;
        this.coder = coder;
        this.onlyExisting = onlyExisting;
    }

    public static <W extends BoundedWindow> StaticWindows of(Coder<W> coder, Iterable<W> windows) {
        checkArgument(!Iterables.isEmpty(windows), "Input windows to StaticWindows may not be empty");
        @SuppressWarnings("unchecked")
        StaticWindows windowFn = new StaticWindows(
                WindowSupplier.of((Coder<BoundedWindow>) coder, (Iterable<BoundedWindow>) windows),
                (Coder<BoundedWindow>) coder, false);
        return windowFn;
    }

    public static <W extends BoundedWindow> StaticWindows of(Coder<W> coder, W window) {
        return of(coder, Collections.singleton(window));
    }

    public StaticWindows intoOnlyExisting() {
        return new StaticWindows(windows, coder, true);
    }

    public Collection<BoundedWindow> getWindows() {
        return windows.get();
    }

    @Override
    public Collection<BoundedWindow> assignWindows(AssignContext c) throws Exception {
        if (onlyExisting) {
            checkArgument(windows.get().contains(c.window()),
                    "Tried to assign windows to an element that is not already windowed into a provided "
                            + "window when onlyExisting is set to true");
            return Collections.singleton(c.window());
        } else {
            return getWindows();
        }
    }

    @Override
    public boolean isCompatible(WindowFn<?, ?> other) {
        if (!(other instanceof StaticWindows)) {
            return false;
        }
        StaticWindows that = (StaticWindows) other;
        return Objects.equals(this.windows.get(), that.windows.get());
    }

    @Override
    public void verifyCompatibility(WindowFn<?, ?> other) throws IncompatibleWindowException {
        if (!this.isCompatible(other)) {
            throw new IncompatibleWindowException(other,
                    String.format("Only %s objects with the same window supplier are compatible.",
                            StaticWindows.class.getSimpleName()));
        }
    }

    @Override
    public Coder<BoundedWindow> windowCoder() {
        return coder;
    }

    @Override
    public WindowMappingFn<BoundedWindow> getDefaultWindowMappingFn() {
        return new WindowMappingFn<BoundedWindow>(Duration.millis(Long.MAX_VALUE)) {
            @Override
            public BoundedWindow getSideInputWindow(BoundedWindow mainWindow) {
                checkArgument(windows.get().contains(mainWindow),
                        "%s only supports side input windows for main input windows that it contains",
                        StaticWindows.class.getSimpleName());
                return mainWindow;
            }
        };
    }

    @Override
    public boolean assignsToOneWindow() {
        return true;
    }
}