/*
* 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.state;
import org.apache.beam.sdk.annotations.Internal;
import org.apache.beam.sdk.options.PipelineOptions;
import org.apache.beam.sdk.transforms.windowing.BoundedWindow;
import org.apache.beam.sdk.values.PCollectionView;
/** <b><i>For internal use only; no backwards-compatibility guarantees.</i></b> */
@Internal
public class StateContexts {
private static final StateContext<BoundedWindow> NULL_CONTEXT =
new StateContext<BoundedWindow>() {
@Override
public PipelineOptions getPipelineOptions() {
throw new IllegalArgumentException("cannot call getPipelineOptions() in a null context");
}
@Override
public <T> T sideInput(PCollectionView<T> view) {
throw new IllegalArgumentException("cannot call sideInput() in a null context");
}
@Override
public BoundedWindow window() {
throw new IllegalArgumentException("cannot call window() in a null context");
}
};
/** Returns a fake {@link StateContext}. */
@SuppressWarnings("unchecked")
public static <W extends BoundedWindow> StateContext<W> nullContext() {
return (StateContext<W>) NULL_CONTEXT;
}
}