external/storm-cassandra/src/main/java/org/apache/storm/cassandra/query/impl/PreparedStatementBinder.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.storm.cassandra.query.impl;

import com.datastax.driver.core.BoundStatement;
import com.datastax.driver.core.CodecRegistry;
import com.datastax.driver.core.PreparedStatement;
import java.io.Serializable;
import java.util.List;
import org.apache.storm.cassandra.query.Column;

public interface PreparedStatementBinder extends Serializable {

    public BoundStatement apply(PreparedStatement statement, List<Column> columns);

    public static final class DefaultBinder implements PreparedStatementBinder {

        /**
         * {@inheritDoc}
         */
        @Override
        public BoundStatement apply(PreparedStatement statement, List<Column> columns) {
            Object[] values = Column.getVals(columns);
            return statement.bind(values);
        }
    }

    @SuppressWarnings("checkstyle:AbbreviationAsWordInName")
    public static final class CQL3NamedSettersBinder implements PreparedStatementBinder {

        /**
         * {@inheritDoc}
         */
        @Override
        public BoundStatement apply(PreparedStatement statement, List<Column> columns) {
            Object[] values = Column.getVals(columns);

            BoundStatement boundStatement = statement.bind();
            for (Column col : columns) {
                // For native protocol V3 or below, all variables must be bound.
                // With native protocol V4 or above, variables can be left unset,
                // in which case they will be ignored server side (no tombstones will be generated).
                if (col.isNull()) {
                    boundStatement.setToNull(col.getColumnName());
                } else {
                    boundStatement.set(col.getColumnName(), col.getVal(),
                                       CodecRegistry.DEFAULT_INSTANCE.codecFor(col.getVal()));
                }
            }
            return statement.bind(values);
        }
    }
}