Design Document for Java APIs for HCATALOG DDL Commands

 package org.apache.hcatalog.api;

import java.util.List;

import org.apache.hcatalog.common.HCatException;
import org.apache.hcatalog.mapreduce.HCatDatabaseInfo;
import org.apache.hcatalog.mapreduce.HCatPartitionInfo;
import org.apache.hcatalog.mapreduce.HCatTableInfo;

/**
 * The Interface HCatClient containing APIs for HCatalog DDL commands.
 */
public interface HCatClient {

    /**
     * Gets the database like.
     *
     * @param regex The regular expression. Providing "*" would retrieve all the names
     *              of the databases.
     * @return The list of all the database names.
     * @throws HCatException
     */
    public List<String> getDatabaseLike(String regex) throws HCatException;

    /**
     * Gets the database.
     *
     * @param dbName The name of the database.
     * @return An instance of HCatDatabaseInfo.
     * @throws HCatException
     */
    public HCatDatabaseInfo getDatabase(String dbName) throws HCatException;

    /**
     * Creates the database.
     *
     * @param dbInfo An instance of HCatCreateDBDesc.
     * @return true, if successful
     * @throws HCatException
     */
    public boolean createDatabase(HCatCreateDBDesc dbInfo)
            throws HCatException;

    /**
     * Deletes a database.
     *
     * @param dbName The name of the database to delete.
     * @param ifExists Hive returns an error if the database specified does not exist,
     *                 unless ifExists is set to true.
     * @param mode This is set to either "restrict" or "cascade". Restrict will
     *             remove the schema if all the tables are empty. Cascade removes
     *             everything including data and definitions.
     * @param userGroup The user group to use
     * @param permissions The permissions string to use. The format is "rwxrw-r-x".
     * @return true, if successful
     * @throws HCatException
     */
    public boolean deleteDatabase(String dbName, boolean ifExists, String mode,
            String userGroup, String permissions) throws HCatException;

    /**
     * Gets the tables like a pattern specified.
     *
     * @param dbName The name of the database.
     * @param regex The regular expression. Providing "*" would retrieve all the names
     *              of  the table.
     * @return A list of all table names matching the specified pattern.
     * @throws HCatException
     */
    public List<String> getTablesLike(String dbName, String regex)
            throws HCatException;

    /**
     * Gets the table.
     *
     * @param dbName The name of the database.
     * @param tableName The name of the table.
     * @return An instance of HCatTableInfo.
     * @throws HCatException
     */
    public HCatTableInfo getTable(String dbName, String tableName)
            throws HCatException;

    /**
     * Creates the table.
     *
     * @param createTableDesc An instance of HCatCreateTableDesc class.
     * @return true, if successful.
     * @throws HCatException the h cat exception
     */
    public boolean createTable(HCatCreateTableDesc createTableDesc)
            throws HCatException;

    /**
     * Creates the table like an existing table.
     *
     * @param dbName The name of the database.
     * @param existingTblName The name of the existing table.
     * @param newTableName The name of the new table.
     * @param ifExists the if exists
     * @param isExternal Set to "true", if table has be created at a different
     *                   location other than default.
     * @param location The location for the table.
     * @return true, if successful
     * @throws HCatException
     */
    public boolean createTableLike(String dbName, String existingTblName,
            String newTableName, boolean ifExists, boolean isExternal,
            String location) throws HCatException;

    /**
     * Delete a table.
     *
     * @param dbName The name of the database.
     * @param tableName The name of the table.
     * @param ifExists Hive returns an error if the database specified does not exist,
     *                 unless ifExists is set to true.
     * @param userGroup The user group to use.
     * @param permissions The permissions string to use. The format is "rwxrw-r-x".
     * @return true, if successful
     * @throws HCatException
     */
    public boolean deleteTable(String dbName, String tableName,
            boolean ifExists, String userGroup, String permissions)
            throws HCatException;

    /**
     * Renames a table.
     *
     * @param dbName The name of the database.
     * @param oldName The name of the table to be renamed.
     * @param newName The new name of the table.
     * @param userGroup The user group to use.
     * @param permissions The permissions string to use. The format is "rwxrw-r-x".
     * @return true, if successful
     * @throws HCatException
     */
    public boolean renameTable(String dbName, String oldName, String newName,
            String userGroup, String permissions) throws HCatException;

    /**
     * Gets all the partitions.
     *
     * @param dbName The name of the database.
     * @param tblName The name of the table.
     * @return A list of partition names.
     * @throws HCatException the h cat exception
     */
    public List<HCatPartitionInfo> getPartitions(String dbName, String tblName)
            throws HCatException;

    /**
     * Gets the partition.
     *
     * @param dbName The database name.
     * @param tableName The table name.
     * @param partitionName The partition name, Comma separated list of col_name='value'.
     * @return An instance of HCatPartitionInfo.
     * @throws HCatException
     */
    public HCatPartitionInfo getPartition(String dbName, String tableName,
            String partitionName) throws HCatException;

    /**
     * Adds the partition.
     *
     * @param partInfo An instance of HCatAddPartitionDesc.
     * @return true, if successful
     * @throws HCatException the h cat exception
     */
    public boolean addPartition(HCatAddPartitionDesc partInfo) throws HCatException;

    /**
     * Deletes partition.
     *
     * @param dbName The database name.
     * @param tableName The table name.
     * @param partitionName The partition name, Comma separated list of col_name='value'.
     * @param ifExists Hive returns an error if the partition specified does not exist, unless ifExists is set to true.
     * @param userGroup The user group to use.
     * @param permissions The permissions string to use. The format is "rwxrw-r-x".
     * @return true, if successful
     * @throws HCatException
     */
    public boolean deletePartition(String dbName, String tableName,
            String partitionName, boolean ifExists, String userGroup,
            String permissions) throws HCatException;

    /**
     * List partitions by filter.
     *
     * @param dbName The database name.
     * @param tblName The table name.
     * @param filter The filter string,
     *    for example "part1 = \"p1_abc\" and part2 <= "\p2_test\"". Filtering can
     *    be done only on string partition keys.
     * @return list of partitions
     * @throws HCatException the h cat exception
     */
    public List<HCatPartitionInfo> listPartitionsByFilter(String dbName, String tblName,
            String filter) throws HCatException;

}

public interface CommandProcessor {
  public void init();

  public CommandProcessorResponse run(String command) throws CommandNeedRetryException;
}

/**
 * The Class HCatCommandDesc contains methods which help in validating,
 * building command descriptors and queries.
 */
public abstract class HCatCommandDesc{

    public abstract void validateCommandDesc() throws HCatException;
    abstract String buildQuery() throws HCatException;
    abstract boolean isValidationComplete();

}