flink-table/flink-table-api-java-bridge/src/main/java/org/apache/flink/table/factories/BlackHoleTableSinkFactory.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.table.factories;

import org.apache.flink.annotation.PublicEvolving;
import org.apache.flink.configuration.ConfigOption;
import org.apache.flink.streaming.api.functions.sink.DiscardingSink;
import org.apache.flink.table.connector.ChangelogMode;
import org.apache.flink.table.connector.sink.DynamicTableSink;
import org.apache.flink.table.connector.sink.SinkFunctionProvider;
import org.apache.flink.types.RowKind;

import java.util.HashSet;
import java.util.Set;

import static org.apache.flink.table.factories.FactoryUtil.createTableFactoryHelper;

/**
 * Black hole table sink factory swallowing all input records. It is designed for: - high
 * performance testing. - UDF to output, not substantive sink. Just like /dev/null device on
 * Unix-like operating systems.
 */
@PublicEvolving
public class BlackHoleTableSinkFactory implements DynamicTableSinkFactory {

    public static final String IDENTIFIER = "blackhole";

    @Override
    public String factoryIdentifier() {
        return IDENTIFIER;
    }

    @Override
    public Set<ConfigOption<?>> requiredOptions() {
        return new HashSet<>();
    }

    @Override
    public Set<ConfigOption<?>> optionalOptions() {
        return new HashSet<>();
    }

    @Override
    public DynamicTableSink createDynamicTableSink(Context context) {
        createTableFactoryHelper(this, context).validate();
        return new BlackHoleSink();
    }

    private static class BlackHoleSink implements DynamicTableSink {

        @Override
        public ChangelogMode getChangelogMode(ChangelogMode requestedMode) {
            ChangelogMode.Builder builder = ChangelogMode.newBuilder();
            for (RowKind kind : requestedMode.getContainedKinds()) {
                if (kind != RowKind.UPDATE_BEFORE) {
                    builder.addContainedKind(kind);
                }
            }
            return builder.build();
        }

        @Override
        public SinkRuntimeProvider getSinkRuntimeProvider(DynamicTableSink.Context context) {
            return SinkFunctionProvider.of(new DiscardingSink<>());
        }

        @Override
        public DynamicTableSink copy() {
            return new BlackHoleSink();
        }

        @Override
        public String asSummaryString() {
            return "BlackHole";
        }
    }
}