/*
* 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.util;
import org.apache.beam.sdk.options.PipelineOptions;
import org.apache.beam.sdk.state.StateContext;
import org.apache.beam.sdk.transforms.CombineWithContext.Context;
import org.apache.beam.sdk.values.PCollectionView;
/**
* Factory that produces {@code Combine.Context} based on different inputs.
*/
public class CombineContextFactory {
private static final Context NULL_CONTEXT = new Context() {
@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");
}
};
/**
* Returns a fake {@code Combine.Context} for tests.
*/
public static Context nullContext() {
return NULL_CONTEXT;
}
/**
* Returns a {@code Combine.Context} that wraps a {@link StateContext}.
*/
public static Context createFromStateContext(final StateContext<?> c) {
return new Context() {
@Override
public PipelineOptions getPipelineOptions() {
return c.getPipelineOptions();
}
@Override
public <T> T sideInput(PCollectionView<T> view) {
return c.sideInput(view);
}
};
}
}