external/storm-cassandra/src/main/java/org/apache/storm/cassandra/query/impl/RoutingKeyGenerator.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.CodecRegistry;
import com.datastax.driver.core.ProtocolVersion;
import com.google.common.base.Preconditions;
import java.io.Serializable;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.List;
import org.apache.storm.tuple.ITuple;

public class RoutingKeyGenerator implements Serializable {

    private List<String> routingKeys;

    /**
     * Creates a new {@link RoutingKeyGenerator} instance.
     * @param routingKeys
     */
    public RoutingKeyGenerator(List<String> routingKeys) {
        Preconditions.checkNotNull(routingKeys);
        this.routingKeys = routingKeys;
    }

    public List<ByteBuffer> getRoutingKeys(ITuple tuple) {
        List<ByteBuffer> keys = new ArrayList<>(routingKeys.size());
        for (String s : routingKeys) {
            Object value = tuple.getValueByField(s);
            ByteBuffer serialized = CodecRegistry.DEFAULT_INSTANCE.codecFor(value).serialize(value, ProtocolVersion.NEWEST_SUPPORTED);
            keys.add(serialized);
        }
        return keys;
    }
}