org.apache.flink.batch.connectors.cassandra.CassandraInputFormat Maven / Gradle / Ivy
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* 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.batch.connectors.cassandra;
import org.apache.flink.api.java.tuple.Tuple;
import org.apache.flink.core.io.InputSplit;
import org.apache.flink.streaming.connectors.cassandra.ClusterBuilder;
import com.datastax.driver.core.ResultSet;
import com.datastax.driver.core.Row;
import java.io.IOException;
/**
* InputFormat to read data from Apache Cassandra and generate ${@link Tuple}.
*
* @param type of Tuple
*/
public class CassandraInputFormat extends CassandraInputFormatBase {
private static final long serialVersionUID = 3642323148032444264L;
private transient ResultSet resultSet;
public CassandraInputFormat(String query, ClusterBuilder builder) {
super(query, builder);
}
/**
* Opens a Session and executes the query.
*
* @param ignored because parameter is not parallelizable.
* @throws IOException
*/
@Override
public void open(InputSplit ignored) throws IOException {
this.session = cluster.connect();
this.resultSet = session.execute(query);
}
@Override
public boolean reachedEnd() throws IOException {
return resultSet.isExhausted();
}
@Override
public OUT nextRecord(OUT reuse) throws IOException {
final Row item = resultSet.one();
for (int i = 0; i < reuse.getArity(); i++) {
reuse.setField(item.getObject(i), i);
}
return reuse;
}
}