Design Document - Java APIs for HCatalog DDL Commands

/**
 * The abstract class HCatClient containing APIs for HCatalog DDL commands.
 */
public abstract class HCatClient {

    /**
     * Creates an instance of HCatClient.
     *
     * @param conf An instance of configuration.
     * @return An instance of HCatClient.
     */
    public static HCatClient create(Configuration conf){
        // Obtain details of implementation class and return an instance.
    }

    /**
     * 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 abstract List<String> getDatabases(String regex) throws HCatException;

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

    /**
     * Creates the database.
     *
     * @param dbInfo An instance of HCatCreateDBDesc.
     * @return true, if successful
     * @throws HCatException
     */
    public abstract 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 abstract 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 abstract List<String> getTables(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 abstract HCatTable 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 abstract 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 abstract 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 abstract 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 abstract 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 abstract List<HCatPartition> 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 abstract HCatPartition 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 abstract 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 abstract 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 abstract List<HCatPartition> listPartitionsByFilter(String dbName, String tblName,
            String filter) throws HCatException;

    /**
     * Mark partition for event.
     *
     * @param dbName The database name.
     * @param tblName The table name.
     * @param partKVs the part k vs
     * @param eventType the event type
     * @throws HCatException the h cat exception
     */
    public abstract void markPartitionForEvent(String dbName, String tblName,
            Map<String, String> partKVs, PartitionEventType eventType)
            throws HCatException;

    /**
     * Checks if is partition marked for event.
     *
     * @param dbName the db name
     * @param tblName the tbl name
     * @param partKVs the part k vs
     * @param eventType the event type
     * @return true, if is partition marked for event
     * @throws HCatException the h cat exception
     */
    public abstract boolean isPartitionMarkedForEvent(String dbName, String tblName,
            Map<String, String> partKVs, PartitionEventType eventType)
            throws HCatException;

    /**
     * Gets the delegation token.
     *
     * @param owner the owner
     * @param renewerKerberosPrincipalName the renewer kerberos principal name
     * @return the delegation token
     * @throws HCatException the h cat exception
     */
    public abstract String getDelegationToken(String owner, String renewerKerberosPrincipalName) throws
        HCatException;

    /**
     * Renew delegation token.
     *
     * @param tokenStrForm the token str form
     * @return the long
     * @throws HCatException the h cat exception
     */
    public abstract long renewDelegationToken(String tokenStrForm) throws HCatException;

    /**
     * Cancel delegation token.
     *
     * @param tokenStrForm the token str form
     * @throws HCatException the h cat exception
     */
    public abstract void cancelDelegationToken(String tokenStrForm) throws HCatException;

}

abstract class HCatCommandDesc{

     String dbName;
     String userGroup;
     String permissions;

   protected static abstract class Builder {

        String innerUserGroup;
         String innerPerms;
         String innerDBName;

         protected Builder(String dbName){
            this.innerDBName = dbName;
        }

        public Builder setUserGroup(String user){
            this.innerUserGroup = user;
            return this;
        }

        /**
         * Sets the permissions.
         *
         * @param perms The permissions string to use. The format is "rwxrw-r-x".
         */
        protected Builder setPermissions(String perms){
            this.innerPerms = perms;
            return this;
        }

        protected abstract HCatCommandDesc build() throws HCatException;


    }

    protected HCatCommandDesc(String dbName, String userGroup, String permissions) {
    this.dbName = dbName;
    this.userGroup = userGroup;
    this.permissions = permissions;
}

    public String getDatabaseName() {
        return this.dbName;
    }

    public String getUserGroup(){
        return this.userGroup;
    }


    public String getPermissions(){
        return this.permissions;
    }


}

 Configuration config = new Configuration();
 config.add("hive-site.xml");
 HCatClient client = HCatClient.create(config);
 ArrayList<HCatFieldSchema> cols = new ArrayList<HCatFieldSchema>();
 cols.add(new HCatFieldSchema("col1", Type.INT, "comment1"));
 cols.add(new HCatFieldSchema("col2", Type.STRING, "comment2"));
HCatCreateTableDesc desc = new HCatCreateTableDesc.Builder("default","demo_table").setFileFormat("rcfile").setCols(cols).build();

 boolean success = client.createTable(desc);