statefun-flink/statefun-flink-core/src/main/java/org/apache/flink/statefun/flink/core/translation/EgressToSinkTranslator.java

/*
 * 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.flink.statefun.flink.core.translation;

import java.util.Map;
import java.util.Objects;
import org.apache.flink.statefun.flink.core.StatefulFunctionsUniverse;
import org.apache.flink.statefun.flink.core.common.Maps;
import org.apache.flink.statefun.flink.io.spi.SinkProvider;
import org.apache.flink.statefun.sdk.io.EgressIdentifier;
import org.apache.flink.statefun.sdk.io.EgressSpec;
import org.apache.flink.streaming.api.functions.sink.SinkFunction;

final class EgressToSinkTranslator {
  private final StatefulFunctionsUniverse universe;

  EgressToSinkTranslator(StatefulFunctionsUniverse universe) {
    this.universe = Objects.requireNonNull(universe);
  }

  Map<EgressIdentifier<?>, DecoratedSink> translate() {
    return Maps.transformValues(universe.egress(), this::sinkFromSpec);
  }

  private DecoratedSink sinkFromSpec(EgressIdentifier<?> key, EgressSpec<?> spec) {
    SinkProvider provider = universe.sinks().get(spec.type());
    if (provider == null) {
      throw new IllegalStateException(
          "Unable to find a sink translation for egress of type "
              + spec.type()
              + ", which is bound for key "
              + key);
    }
    SinkFunction<?> sink = provider.forSpec(spec);
    if (sink == null) {
      throw new NullPointerException(
          "A sink provider for type " + spec.type() + ", has produced a NULL sink.");
    }
    return DecoratedSink.of(spec, sink);
  }
}