ch.ethz.mxquery.opt.expr
Class LogicalUnit

java.lang.Object
  ch.ethz.mxquery.opt.expr.LogicalUnit

All Implemented Interfaces:

Traversable, java.lang.Cloneable, java.lang.Comparable

Direct Known Subclasses:

Literal, Term

public abstract class LogicalUnit
extends java.lang.Object
implements java.lang.Comparable, java.lang.Cloneable, Traversable

Every term and literal inherits from logical unit. This calls introduces some helper methods

Field Summary

static int	DEPENDENCY_END
static int	DEPENDENCY_NO
static int	DEPENDENCY_START
static int	DEPENDENCY_STARTEND
static int	INDEX_IMPOSSIBLE
static int	INDEX_POSSIBLE
static int	INDEX_RECOMMEND
static int	RESET
static int	RESULT_FALSE
static int	RESULT_TRUE
static int	RESULT_UNKNOWN

Constructor Summary

LogicalUnit()

Method Summary

void	addDependency(int dep) Adds a new dependency to the logical unit
int	compareTo(java.lang.Object o) Compares to logical units according to their dependencies
abstract int	evaluate(int level) Evaluates the logical unit until a certain degree on variable dependency and returns if the result is false, true or unknown
int	getDependency()
static java.lang.String	getDependencyName(int dependency)
static int	getDependencyNb(boolean start, boolean end) Returns for the combination of start and end variable the corresponding constant
int	getResult() Returns if the result if the result if false, ture or unknown
static boolean	isDependendOnEnd(int dependency) Test if it depends on the end variables
static boolean	isDependendOnStart(int dependency) Test if it depends on the start variables
boolean	isIndexable() Returns if for this logical unit a index is recommended.
boolean	isLowerDependency(int dep1, int dep2) Compares two dependecies.
boolean	isLowerOrEqualDependency(int dep1, int dep2) Compares to dependencies to each other
int	reset(int level) Resets the logical unit up to a certain degree on variable dependency
void	setDependency(int dep)
void	setIndexable(int value) Sets if a logical unit is indexable.
KXmlSerializer	traverse(KXmlSerializer serializer)

Methods inherited from class java.lang.Object

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

Field Detail

RESET

public static final int RESET

See Also:

Constant Field Values

DEPENDENCY_NO

public static final int DEPENDENCY_NO

See Also:

Constant Field Values

DEPENDENCY_START

public static final int DEPENDENCY_START

See Also:

Constant Field Values

DEPENDENCY_END

public static final int DEPENDENCY_END

See Also:

Constant Field Values

DEPENDENCY_STARTEND

public static final int DEPENDENCY_STARTEND

See Also:

Constant Field Values

RESULT_FALSE

public static final int RESULT_FALSE

See Also:

Constant Field Values

RESULT_UNKNOWN

public static final int RESULT_UNKNOWN

See Also:

Constant Field Values

RESULT_TRUE

public static final int RESULT_TRUE

See Also:

Constant Field Values

INDEX_POSSIBLE

public static final int INDEX_POSSIBLE

See Also:

Constant Field Values

INDEX_RECOMMEND

public static final int INDEX_RECOMMEND

See Also:

Constant Field Values

INDEX_IMPOSSIBLE

public static final int INDEX_IMPOSSIBLE

See Also:

Constant Field Values

Constructor Detail

LogicalUnit

public LogicalUnit()

Method Detail

getDependency

public int getDependency()

setDependency

public void setDependency(int dep)

compareTo

public int compareTo(java.lang.Object o)

Compares to logical units according to their dependencies

Specified by:

compareTo in interface java.lang.Comparable

Parameters:

o -

Returns:

-1 of this logical unit is small, 0 if equal, 1 if this is greater

reset

public int reset(int level)

Resets the logical unit up to a certain degree on variable dependency

Parameters:

level -

Returns:

UNKNOWN, TRUE or FALSE

evaluate

public abstract int evaluate(int level)
                      throws MXQueryException

Evaluates the logical unit until a certain degree on variable dependency and returns if the result is false, true or unknown

Parameters:

level - Up to this dependency level the unit is evaluated

Returns:

false, true or unknown

Throws:

MXQueryException

isLowerOrEqualDependency

public boolean isLowerOrEqualDependency(int dep1,
                                        int dep2)

Compares to dependencies to each other

Parameters:

dep1 -

dep2 -

Returns:

true if equals or lower dependency

isIndexable

public boolean isIndexable()

Returns if for this logical unit a index is recommended.

Returns:

true if an index is recommended, false otherwise

setIndexable

public void setIndexable(int value)

Sets if a logical unit is indexable. But only following changes are allowed:
INDEX_POSSIBLE --> INDEX_RECOMMEND INDEX_POSSIBLE --> INDEX_IMPOSSIBLE INDEX_RECOMMEND --> INDEX_IMPOSSIBLE

Parameters:

value -

isLowerDependency

public boolean isLowerDependency(int dep1,
                                 int dep2)

Compares two dependecies. The order is as follows RESET < DEPENDENCY_NO < DEPENDENCY_START | DEPENDENCY_END < DEPENDENCY_STARTEND

Parameters:

dep1 -

dep2 -

Returns:

true of dep1 has a lower dependency

addDependency

public void addDependency(int dep)

Adds a new dependency to the logical unit

Parameters:

dep -

isDependendOnStart

public static boolean isDependendOnStart(int dependency)

Test if it depends on the start variables

Parameters:

dependency -

Returns:

true of there is a dependency on start variables

isDependendOnEnd

public static boolean isDependendOnEnd(int dependency)

Test if it depends on the end variables

Parameters:

dependency -

Returns:

true of there is a dependency on end variables

getDependencyName

public static java.lang.String getDependencyName(int dependency)

getDependencyNb

public static int getDependencyNb(boolean start,
                                  boolean end)

Returns for the combination of start and end variable the corresponding constant

Parameters:

start - Depends on the start variable

end - Depends on the end variable

Returns:

the correct dependency class

getResult

public int getResult()

Returns if the result if the result if false, ture or unknown

Returns:

the predicate index result

traverse

public KXmlSerializer traverse(KXmlSerializer serializer)

Specified by:

traverse in interface Traversable