mondrian.olap
Interface Evaluator

All Known Implementing Classes:

RolapDependencyTestingEvaluator, RolapEvaluator, RolapProfilingEvaluator

public interface Evaluator

An Evaluator holds the context necessary to evaluate an expression.

Since:

27 July, 2001

Author:

jhyde

Nested Class Summary

static interface

Evaluator.NamedSetEvaluator Interface for evaluating a particular named set.

Method Summary

boolean	currentIsEmpty() Returns whether the current context is an empty cell.
Object	evaluateCurrent() Calculates and returns the value of the cell at the current context.
String	format(Object o) Formats a value as a string according to the current context's format.
String	format(Object o, String formatString) Formats a value as a string according to the current context's format, using a given format string.
Object	getCachedResult(ExpCacheDescriptor key) Simple caching of the result of an Exp.
Locale	getConnectionLocale() Returns the connection's locale.
Member	getContext(Hierarchy hierarchy)
Cube	getCube() Returns the current cube.
int	getDepth() Deprecated. Will be removed in mondrian-4
String	getFormatString() Returns the format string for this cell.
int	getIterationLength()
Cube	getMeasureCube() Returns the base (non-virtual) cube that the current measure in the context belongs to.
Member[]	getMembers() Returns an array of the members which make up the current context.
int	getMissCount() Returns the number of times that this evaluator has told a lie when retrieving cell values.
Evaluator.NamedSetEvaluator	getNamedSetEvaluator(NamedSet namedSet, boolean create) Returns an evaluator for a named set.
Member[]	getNonAllMembers() Returns an array of the non-All members which make up the current context.
Object	getParameterValue(ParameterSlot slot) Returns the value of a parameter, evaluating its default value if it is not set.
Evaluator	getParent() Deprecated. Will be removed in mondrian-4
Member	getPreviousContext(Hierarchy hierarchy) Returns the member that was the current evaluation context for a particular hierarchy before the most recent change in context.
Object	getProperty(String name, Object defaultValue) Retrieves the value of property name.
Query	getQuery() Returns the current query.
Date	getQueryStartTime() Returns the start time of the current query.
SchemaReader	getSchemaReader() Returns a SchemaReader appropriate for the current access-control context.
QueryTiming	getTiming() Returns the query timing context for this execution.
boolean	isEvalAxes()
boolean	isNonEmpty() Returns true for an axis that is NON EMPTY.
boolean	mightReturnNullForUnrelatedDimension() Returns whether it is necessary to check whether to return null for an unrelated dimension.
boolean	nativeEnabled() Returns whether native evaluation is enabled in this context.
boolean	needToReturnNullForUnrelatedDimension(Member[] members) If IgnoreMeasureForNonJoiningDimension is set to true and one or more members are on unrelated dimension for the measure in current context then returns true.
RuntimeException	newEvalException(Object context, String s) Creates an exception which indicates that an error has occurred during the runtime evaluation of a function.
Evaluator	push() Creates a new Evaluator with the same context as this evaluator.
Evaluator	push(boolean nonEmpty) Deprecated. Use savepoint() followed by setNonEmpty(boolean); will be removed in mondrian-4
Evaluator	push(boolean nonEmpty, boolean nativeEnabled) Deprecated. Use savepoint() followed by setNonEmpty(boolean) and setNativeEnabled(boolean); will be removed in mondrian-4.
Evaluator	push(Member member) Deprecated. Use savepoint() followed by setContext(Member); will be removed in mondrian-4
Evaluator	push(Member[] members) Deprecated. Use savepoint() followed by setContext(Member[]); will be removed in mondrian-4
Evaluator	pushAggregation(List<List<Member>> list) Returns a new Aggregator whose aggregation context adds a given list of tuples, and whose evaluation context is the same as this Aggregator.
void	restore(int savepoint) Restores previous evaluator.
int	savepoint() Creates a savepoint encapsulating the current state of the evalutor.
void	setContext(List<Member> memberList) Sets the context to a list of members.
void	setContext(List<Member> memberList, boolean safe) Sets the context to a list of members, optionally skipping the check whether it is necessary to store the previous member of each hierarchy.
Member	setContext(Member member) Makes member the current member of its hierarchy.
void	setContext(Member[] members) Sets the context to an array of members.
void	setContext(Member[] members, boolean safe) Sets the context to an array of members, optionally skipping the check whether it is necessary to store the previous member of each hierarchy.
void	setContext(Member member, boolean safe) Makes member the current member of its hierarchy.
void	setEvalAxes(boolean evalAxes) Indicate whether the evaluator is evaluating the axes
void	setIterationLength(int length) Sets the iteration length for the current evaluator context
void	setNativeEnabled(boolean nativeEnabled) Sets whether native evaluation should be used.
void	setNonEmpty(boolean nonEmpty) Sets whether an expression evaluation should filter out empty cells.
boolean	shouldIgnoreUnrelatedDimensions() Returns whether hierarchies unrelated to the measure in the current context should be ignored.

Method Detail

getCube

Cube getCube()

Returns the current cube.

getQuery

Query getQuery()

Returns the current query.

getQueryStartTime

Date getQueryStartTime()

Returns the start time of the current query.

savepoint

int savepoint()

Creates a savepoint encapsulating the current state of the evalutor. You can restore the evaluator to this state by calling restore(int) with the value returned by this method.

This method is typically called before evaluating an expression which is known to corrupt the evaluation context.

Multiple savepoints may be active at the same time for the same evaluator. And, it is allowable to restore to the save savepoint more than once (or not at all). However, when you have rolled back to a particular savepoint you may not restore to a later savepoint.

Returns:

Evaluator with each given member overriding the state of the current Evaluator for its hierarchy

push

Evaluator push(Member[] members)

Deprecated. Use savepoint() followed by setContext(Member[]); will be removed in mondrian-4

Creates a new Evaluator with each given member overriding the context of the current Evaluator for its hierarchy. Other hierarchies retain the same context as this Evaluator.

In mondrian-3.3 and later, a more efficient way to save the state of an evaluator is to call savepoint() followed by restore(int). We recommend using those methods.

Parameters:

members - Array of members to add to the context

Returns:

Evaluator with each given member overriding the state of the current Evaluator for its hierarchy

push

Evaluator push()

Creates a new Evaluator with the same context as this evaluator.

This method is typically called before evaluating an expression which may corrupt the evaluation context.

In mondrian-3.3 and later, a more efficient way to save the state of an evaluator is to call savepoint() followed by restore(int). We recommend using those methods most of the time.

However, it makes sense to use this method in the constructor of an iterator. It allows the iterator to modify its evaluation context without affecting the evaluation context of the calling code. This behavior cannot be achieved using savepoint.

Returns:

Evaluator with each given member overriding the state of the current Evaluator for its hierarchy

push

Evaluator push(Member member)

Deprecated. Use savepoint() followed by setContext(Member); will be removed in mondrian-4

Creates a new Evaluator with the same context except for one member.

This method is typically called before evaluating an expression which may corrupt the evaluation context.

In mondrian-3.3 and later, a more efficient way to save the state of an evaluator is to call savepoint() followed by restore(int). We recommend using those methods.

Parameters:

member - Member to add to the context

Returns:

Evaluator with each given member overriding the state of the current Evaluator for its hierarchy

push

Evaluator push(boolean nonEmpty)

Deprecated. Use savepoint() followed by setNonEmpty(boolean); will be removed in mondrian-4

Creates a new evaluator with the same state except nonEmpty property

In mondrian-3.3 and later, a more efficient way to save the state of an evaluator is to call savepoint() followed by restore(int). We recommend using those methods.

push

Evaluator push(boolean nonEmpty,
               boolean nativeEnabled)

Deprecated. Use savepoint() followed by setNonEmpty(boolean) and setNativeEnabled(boolean); will be removed in mondrian-4.

Creates a new evaluator with the same state except nonEmpty and nativeEnabled properties.

In mondrian-3.3 and later, a more efficient way to save the state of an evaluator is to call savepoint() followed by restore(int). We recommend using those methods.

restore

void restore(int savepoint)

Restores previous evaluator.

Parameters:

savepoint - Savepoint returned by savepoint()

setContext

Member setContext(Member member)

Makes member the current member of its hierarchy.

Parameters:

member - New member

Returns:

Previous member of this hierarchy

setContext

void setContext(Member member,
                boolean safe)

Makes member the current member of its hierarchy.

If safe, checks whether this is the first time that a member of this hierarchy has been changed since savepoint() was called. If so, saves the previous member. If safe is false, never saves the previous member.

Use safe = false only if you are sure that the context has been set before. For example,

int n = 0;
for (Member member : members) {
evaluator.setContext(member, n++ > 0);
}


Parameters:

member - New member

safe - Whether to store the member of this hierarchy that was current last time that savepoint() was called.

setContext

void setContext(List<Member> memberList)

Sets the context to a list of members.

Equivalent to

for (Member member : memberList) {
setContext(member);
}


Parameters:

memberList - List of members

setContext

void setContext(List<Member> memberList,
                boolean safe)

Sets the context to a list of members, optionally skipping the check whether it is necessary to store the previous member of each hierarchy.

Equivalent to

for (Member member : memberList) {
setContext(member, safe);
}


Parameters:

memberList - List of members

safe - Whether to store the member of each hierarchy that was current last time that savepoint() was called.

setContext

void setContext(Member[] members)

Sets the context to an array of members.

Equivalent to

for (Member member : memberList) {
setContext(member);
}


Parameters:

members - Array of members

setContext

void setContext(Member[] members,
                boolean safe)

Sets the context to an array of members, optionally skipping the check whether it is necessary to store the previous member of each hierarchy.

Equivalent to

for (Member member : memberList) {
setContext(member, safe);
}


Parameters:

members - Array of members

safe - Whether to store the member of each hierarchy that was current last time that savepoint() was called.

getContext

Member getContext(Hierarchy hierarchy)

evaluateCurrent

Object evaluateCurrent()

Calculates and returns the value of the cell at the current context.

getFormatString

String getFormatString()

Returns the format string for this cell. This is computed by evaluating the format expression in the current context, and therefore different cells may have different format strings.

format

String format(Object o)

Formats a value as a string according to the current context's format.

format

String format(Object o,
              String formatString)

Formats a value as a string according to the current context's format, using a given format string.

getDepth

int getDepth()

Deprecated. Will be removed in mondrian-4

Obsolete method.

getParent

Evaluator getParent()

Deprecated. Will be removed in mondrian-4

Returns parent evaluator.

getConnectionLocale

Locale getConnectionLocale()

Returns the connection's locale.

getProperty

Object getProperty(String name,
                   Object defaultValue)

Retrieves the value of property name. If more than one member in the current context defines that property, the one with the highest solve order has precedence.

If the property is not defined, default value is returned.

getSchemaReader

SchemaReader getSchemaReader()

Returns a SchemaReader appropriate for the current access-control context.

getCachedResult

Object getCachedResult(ExpCacheDescriptor key)

Simple caching of the result of an Exp. The key for the cache consists of all members of the current context that exp depends on. Members of independent hierarchies are not part of the key.

See Also:

Calc.dependsOn(Hierarchy)

isNonEmpty

boolean isNonEmpty()

Returns true for an axis that is NON EMPTY.

May be used by expression evaluators to optimize their result. For example, a top-level crossjoin may be optimized by removing all non-empty set elements before performing the crossjoin. This is possible because of the identity

nonempty(crossjoin(a, b)) == nonempty(crossjoin(nonempty(a), nonempty(b));

setNonEmpty

void setNonEmpty(boolean nonEmpty)

Sets whether an expression evaluation should filter out empty cells. Allows expressions to modify non empty flag to evaluate their children.

newEvalException

RuntimeException newEvalException(Object context,
                                  String s)

Creates an exception which indicates that an error has occurred during the runtime evaluation of a function. The caller should then throw that exception.

getNamedSetEvaluator

Evaluator.NamedSetEvaluator getNamedSetEvaluator(NamedSet namedSet,
                                                 boolean create)

Returns an evaluator for a named set.

Parameters:

namedSet - Named set

create - Whether to create evaluator if not found

Returns:

Evaluator of named set

getMembers

Member[] getMembers()

Returns an array of the members which make up the current context.

getNonAllMembers

Member[] getNonAllMembers()

Returns an array of the non-All members which make up the current context.

Notes:

• The 0th element is a measure, but otherwise the order of the members is unspecified.
• No hierarchy occurs more than once.
• In rare circumstances, some of the members may be an 'All' member.
• The list may contain calculated members.

getMissCount

int getMissCount()

Returns the number of times that this evaluator has told a lie when retrieving cell values.

getParameterValue

Object getParameterValue(ParameterSlot slot)

Returns the value of a parameter, evaluating its default value if it is not set.

getIterationLength

int getIterationLength()

Returns:

the iteration length of the current context

setIterationLength

void setIterationLength(int length)

Sets the iteration length for the current evaluator context

Parameters:

length - length to be set

isEvalAxes

boolean isEvalAxes()

Returns:

true if evaluating axes

setEvalAxes

void setEvalAxes(boolean evalAxes)

Indicate whether the evaluator is evaluating the axes

Parameters:

evalAxes - true if evaluating axes

pushAggregation

Evaluator pushAggregation(List<List<Member>> list)

Returns a new Aggregator whose aggregation context adds a given list of tuples, and whose evaluation context is the same as this Aggregator.

Parameters:

list - List of tuples

Returns:

Aggregator with list added to its aggregation context

shouldIgnoreUnrelatedDimensions

boolean shouldIgnoreUnrelatedDimensions()

Returns whether hierarchies unrelated to the measure in the current context should be ignored.

Returns:

whether hierarchies unrelated to the measure in the current context should be ignored

getMeasureCube

Cube getMeasureCube()

Returns the base (non-virtual) cube that the current measure in the context belongs to.

Returns:

Cube

mightReturnNullForUnrelatedDimension

boolean mightReturnNullForUnrelatedDimension()

Returns whether it is necessary to check whether to return null for an unrelated dimension. If false, we never need to check: we can assume that needToReturnNullForUnrelatedDimension(mondrian.olap.Member[]) will always return false.

Returns:

whether it is necessary to check whether to return null for an unrelated dimension

needToReturnNullForUnrelatedDimension

boolean needToReturnNullForUnrelatedDimension(Member[] members)

If IgnoreMeasureForNonJoiningDimension is set to true and one or more members are on unrelated dimension for the measure in current context then returns true.

You must not call this method unless mightReturnNullForUnrelatedDimension() has returned true.

Parameters:

members - Dimensions for the members need to be checked whether related or unrelated

Returns:

boolean

nativeEnabled

boolean nativeEnabled()

Returns whether native evaluation is enabled in this context.

Returns:

whether native evaluation is enabled in this context

setNativeEnabled

void setNativeEnabled(boolean nativeEnabled)

Sets whether native evaluation should be used.

Parameters:

nativeEnabled - Whether native evaluation should be used

currentIsEmpty

boolean currentIsEmpty()

Returns whether the current context is an empty cell.

Returns:

Whether the current context is an empty cell

getPreviousContext

Member getPreviousContext(Hierarchy hierarchy)

Returns the member that was the current evaluation context for a particular hierarchy before the most recent change in context.

Parameters:

hierarchy - Hierarchy

Returns:

Previous context member for given hierarchy

getTiming

QueryTiming getTiming()

Returns the query timing context for this execution.

Returns:

query timing context