flink-connectors/flink-connector-cassandra/src/main/java/org/apache/flink/streaming/connectors/cassandra/CassandraAppendTableSink.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.streaming.connectors.cassandra;

import org.apache.flink.streaming.api.datastream.DataStream;
import org.apache.flink.streaming.api.datastream.DataStreamSink;
import org.apache.flink.table.api.types.DataType;
import org.apache.flink.table.api.types.DataTypes;
import org.apache.flink.table.api.types.InternalType;
import org.apache.flink.table.sinks.AppendStreamTableSink;
import org.apache.flink.table.util.TableConnectorUtil;
import org.apache.flink.types.Row;
import org.apache.flink.util.Preconditions;

import java.util.Properties;

/**
 * An {@link AppendStreamTableSink} to write an append stream Table to a Cassandra table.
 */
public class CassandraAppendTableSink implements AppendStreamTableSink<Row> {

	private final ClusterBuilder builder;
	private final String cql;
	private String[] fieldNames;
	private DataType[] fieldTypes;
	private final Properties properties;

	public CassandraAppendTableSink(ClusterBuilder builder, String cql) {
		this.builder = Preconditions.checkNotNull(builder, "ClusterBuilder must not be null.");
		this.cql = Preconditions.checkNotNull(cql, "CQL query must not be null.");
		this.properties = new Properties();
	}

	public CassandraAppendTableSink(ClusterBuilder builder, String cql, Properties properties) {
		this.builder = Preconditions.checkNotNull(builder, "ClusterBuilder must not be null.");
		this.cql = Preconditions.checkNotNull(cql, "CQL query must not be null.");
		this.properties = Preconditions.checkNotNull(properties, "Properties must not be null.");
	}

	@Override
	public DataType getOutputType() {
		InternalType[] tmp = new InternalType[fieldTypes.length];
		for (int i = 0; i < fieldTypes.length; i++) {
			tmp[i] = (InternalType) fieldTypes[i];
		}
		return DataTypes.createRowType(tmp, fieldNames);
	}

	@Override
	public String[] getFieldNames() {
		return this.fieldNames;
	}

	@Override
	public DataType[] getFieldTypes() {
		return this.fieldTypes;
	}

	@Override
	public CassandraAppendTableSink configure(String[] fieldNames, DataType[] fieldTypes) {
		CassandraAppendTableSink cassandraTableSink = new CassandraAppendTableSink(this.builder, this.cql, this.properties);
		cassandraTableSink.fieldNames = Preconditions.checkNotNull(fieldNames, "Field names must not be null.");
		cassandraTableSink.fieldTypes = Preconditions.checkNotNull(fieldTypes, "Field types must not be null.");
		Preconditions.checkArgument(fieldNames.length == fieldTypes.length,
			"Number of provided field names and types does not match.");
		return cassandraTableSink;
	}

	@Override
	public DataStreamSink emitDataStream(DataStream<Row> dataStream) {
		try {
			return CassandraSink.addSink(dataStream)
				.setClusterBuilder(this.builder)
				.setQuery(this.cql)
				.build()
				.name(TableConnectorUtil.generateRuntimeName(this.getClass(), fieldNames))
				.getSink1();
		} catch (Exception e) {
			throw new RuntimeException(e);
		}
	}
}