com.hmsonline.storm.cassandra.bolt.mapper.TridentTupleMapper Maven / Gradle / Ivy

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package com.hmsonline.storm.cassandra.bolt.mapper;

import java.io.Serializable;
import java.util.List;
import java.util.Map;

import storm.trident.tuple.TridentTuple;

import com.hmsonline.storm.cassandra.exceptions.TupleMappingException;

/**
 * Interface for mapping Trident storm.trident.tuple.TridentTuple
 * objects to Cassandra rows.
 * 
 * @author tgoetz
 *
 * @param  - the Cassandra row key type
 * @param  - the Cassandra column key/name type
 * @param  - the Cassandra column value type
 */
/* TODO tgoetz: This interface is suffering from serious growing pains,
 * which is a good indication that the API needs to be rethought.
 */
public interface TridentTupleMapper extends Serializable {
    /**
     * Given a storm.trident.tuple.TridentTuple object, 
     * return the name of the column family that data should be 
     * written to.
     *
     * @param tuple
     * @return the column family name
     */
    String mapToColumnFamily(TridentTuple tuple) throws TupleMappingException;
    
    /**
     * Given a backtype.storm.tuple.Tuple object, map the keyspace to write to.
     * 
     * @param tuple
     * @return
     */
    String mapToKeyspace(TridentTuple tuple);
    
    /**
     * Given a storm.trident.tuple.TridentTuple object,
     * return an object representing the Cassandra row key.
     * 
     * @param tuple
     * @return
     * @throws TupleMappingException
     */
    K mapToRowKey(TridentTuple tuple) throws TupleMappingException;

    /**
     * Given a storm.trident.tuple.TridentTuple object,
     * return a java.util.Map object representing the 
     * column names/values to persist to Cassandra.
     * 
     * @param tuple
     * @return
     * @throws TupleMappingException
     */
    Map mapToColumns(TridentTuple tuple) throws TupleMappingException;

    /**
     * Given a storm.trident.tuple.TridentTuple object,
     * return a list of column name (column key) objects in order to execute a 
     * slice query against a particular row.
     * 
     * The row key will be determined by the return value of mapToRowKey().
     * 
     * 
     * @param tuple
     * @return
     * @throws TupleMappingException
     */
    List mapToColumnsForLookup(TridentTuple tuple) throws TupleMappingException;

    /**
     * Map a storm.trident.tuple.TridentTuple object 
     * to a an end key in order to perform a Cassandra column range query.
     * 
     * The row key will be determined by the return value of mapToRowKey().
     * 
     * The start key/column will be determined by the value of mapToStartKey().
     * 
     * @param tuple
     * @return
     * @throws TupleMappingException
     */
    C mapToEndKey(TridentTuple tuple) throws TupleMappingException;

    /**
     * 
     * @param tuple
     * @return
     * @throws TupleMappingException
     */
    C mapToStartKey(TridentTuple tuple) throws TupleMappingException;

    boolean shouldDelete(TridentTuple tuple);

    /**
     * Returns the row key class.
     * 
     * @return
     */
    Class getKeyClass();

    /**
     * Returns the coulumn name(key) class.
     * 
     * @return
     */
    Class getColumnNameClass();
    
    
    /**
     * Returns the column value class.
     * 
     * @return
     */
    Class getColumnValueClass();
}