net.sf.saffron.opt
Class TableAccessMap

java.lang.Object
  |
  +--net.sf.saffron.opt.TableAccessMap

public class TableAccessMap

extends Object

TableAccessMap represents the tables accessed by a query plan, with READ/WRITE information.

Version:

$Id: //open/saffron/src/net/sf/saffron/opt/TableAccessMap.java#1 $

Author:

John V. Sichi

Nested Class Summary

private class

TableAccessMap.TableRelVisitor

Field Summary

private Map	accessMap
static String	NO_ACCESS Table is not accessed at all.
static String	READ_ACCESS Table is accessed for read only.
static String	READWRITE_ACCESS Table is accessed for both read and write.
static String	WRITE_ACCESS Table is accessed for write only.

Constructor Summary

TableAccessMap(SaffronRel rel)
Construct a TableAccessMap for all tables accessed by a SaffronRel and its descendants.

Method Summary

Set	getAccessedTables() .
String	getTableAccessMode(SaffronTable table) Determine the access mode of a table.
boolean	isTableAccessed(SaffronTable table) Determine whether a table is accessed at all.
boolean	isTableAccessedForRead(SaffronTable table) Determine whether a table is accessed for read.
boolean	isTableAccessedForWrite(SaffronTable table) Determine whether a table is accessed for write.

Methods inherited from class java.lang.Object

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

Field Detail

accessMap

private Map accessMap

READ_ACCESS

public static final String READ_ACCESS

Table is accessed for read only.

See Also:

Constant Field Values

WRITE_ACCESS

public static final String WRITE_ACCESS

Table is accessed for write only.

See Also:

Constant Field Values

READWRITE_ACCESS

public static final String READWRITE_ACCESS

Table is accessed for both read and write.

See Also:

Constant Field Values

NO_ACCESS

public static final String NO_ACCESS

Table is not accessed at all.

See Also:

Constant Field Values

Constructor Detail

TableAccessMap

public TableAccessMap(SaffronRel rel)

Construct a TableAccessMap for all tables accessed by a SaffronRel and its descendants.

Parameters:

rel - the SaffronRel for which to build the map

Method Detail

isTableAccessed

public boolean isTableAccessed(SaffronTable table)

Determine whether a table is accessed at all.

Parameters:

table - the table of interest

Returns:

true if table is accessed

isTableAccessedForRead

public boolean isTableAccessedForRead(SaffronTable table)

Determine whether a table is accessed for read.

Parameters:

table - the table of interest

Returns:

true if table is accessed for read

isTableAccessedForWrite

public boolean isTableAccessedForWrite(SaffronTable table)

Determine whether a table is accessed for write.

Parameters:

table - the table of interest

Returns:

true if table is accessed for write

getTableAccessMode

public String getTableAccessMode(SaffronTable table)

Determine the access mode of a table.

Parameters:

table - the table of interest

Returns:

one of the _ACCESS constants

getAccessedTables

public Set getAccessedTables()

.

Returns:

an immutable set of all tables accessed