com.google.cloud.dataflow.sdk.testing.StaticWindows.java Source code

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Here is the source code for com.google.cloud.dataflow.sdk.testing.StaticWindows.java

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/*
 * Copyright (C) 2016 Google Inc.
 *
 * Licensed 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 com.google.cloud.dataflow.sdk.testing;

import static com.google.common.base.Preconditions.checkArgument;

import com.google.cloud.dataflow.sdk.coders.Coder;
import com.google.cloud.dataflow.sdk.transforms.windowing.BoundedWindow;
import com.google.cloud.dataflow.sdk.transforms.windowing.NonMergingWindowFn;
import com.google.cloud.dataflow.sdk.transforms.windowing.WindowFn;
import com.google.common.base.Supplier;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Iterables;

import org.joda.time.Instant;

import java.util.Collection;
import java.util.Collections;
import java.util.Objects;

/**
 * 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().containsAll(c.windows()),
                    "Tried to assign windows to an element that is not already windowed into a provided "
                            + "window when onlyExisting is set to true");
            return ImmutableList.copyOf(c.windows());
        } 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 Coder<BoundedWindow> windowCoder() {
        return coder;
    }

    @Override
    public BoundedWindow getSideInputWindow(BoundedWindow window) {
        checkArgument(windows.get().contains(window),
                "StaticWindows only supports side input windows for main input windows that it contains");
        return window;
    }

    @Override
    public Instant getOutputTime(Instant inputTimestamp, BoundedWindow window) {
        return inputTimestamp;
    }
}