org.apache.hadoop.hive.ql.security.authorization.plugin

Class HivePrivilegeObjectUtils.TableLookup<T>

java.lang.Object

org.apache.hadoop.hive.ql.security.authorization.plugin.HivePrivilegeObjectUtils.TableLookup<T>

Direct Known Subclasses:

HivePrivilegeObjectUtils.TablePrivilegeLookup

Enclosing class:

HivePrivilegeObjectUtils

public abstract static class HivePrivilegeObjectUtils.TableLookup<T>
extends Object

A helper enabling efficient lookup of a table in a list by database name, table name.

When filtering a source list of tables by checking their presence in another permission list using the database name, table name, we need to avoid performing a cartesian product. This product stems from checking each table from the source (n tables) by comparing it to each table in the permission list (m permissions), thus an n * m complexity.

This class reduces the complexity of the lookup in the permission by sorting them and using a binary search; the sort cost is m*log(m) and each lookup is log(m), the overall complexity of a check for all tables is in the order of m*log(m) + n*log(m) = (m + n)*log(n), close to m * log(n).

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	TableLookup(List<T> tables) Creates a ByName

Method Summary

Modifier and Type	Method and Description
boolean	contains(T tt) Checks whether a given table is present in this set.
protected abstract String	getDbName(T table)
protected abstract String	getTableName(T table)
T	lookup(String dbName, String tableName) Lookup using dichotomy using order described by database name, table name.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

TableLookup

protected TableLookup(List<T> tables)

Creates a ByName

Parameters:

tables - the tables to consider as a clique

Method Detail

getDbName

protected abstract String getDbName(T table)

Parameters:

table - the table

Returns:

the database name of the table

getTableName

protected abstract String getTableName(T table)

Parameters:

table - the table

Returns:

the table name of the table

lookup

public final T lookup(String dbName,
                      String tableName)

Lookup using dichotomy using order described by database name, table name.

Parameters:

dbName - the database name

tableName - the table name

Returns:

the table if found in the index, null otherwise

contains

public final boolean contains(T tt)

Checks whether a given table is present in this set.

Parameters:

tt - the table to check

Returns:

true if the set contains an item having the same database and table name