org.apache.solr.analytics

Class ExpressionFactory

java.lang.Object

org.apache.solr.analytics.ExpressionFactory

public class ExpressionFactory
extends Object

A factory to parse and create expressions, and capture information about those expressions along the way.

In order to use, first call startRequest() and create all ungrouped expressions, then call createReductionManager(boolean) to get the ungrouped reduction manager.
Then for each grouping call startGrouping() first then create all expressions within that grouping, finally calling createGroupingReductionManager(boolean) to get the reduction manager for that grouping.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	ExpressionFactory.ConstantFunction Used to initialize analytics constants.
static interface	ExpressionFactory.CreatorFunction Used for system analytics functions for initialization.

Field Summary

Fields

Modifier and Type	Field and Description
static char	variableForEachParam The character used to denote the looped parameter in the for each lambda expression
static char	variableForEachSep The character used to denote the start of a for each lambda expression
static String	variableLengthParamSuffix Used to denote a variable length parameter.

Constructor Summary

Constructors

Constructor and Description
ExpressionFactory(IndexSchema schema)

Method Summary

Modifier and Type	Method and Description
ExpressionFactory	addSystemFunction(String functionName, ExpressionFactory.CreatorFunction functionCreator) Add a system function to the expression factory.
void	addSystemFunctions() Add the natively supported functionality.
ExpressionFactory	addSystemVariableFunction(String functionName, String functionParams, String returnSignature) Add a variable function that will be treated like a system function.
ExpressionFactory	addUserDefinedVariableFunction(String functionSignature, String returnSignature) Add a variable function that was defined in an analytics request.
AnalyticsValueStream	createExpression(String expressionStr) Parse and build an expression from the given expression string.
ReductionCollectionManager	createGroupingReductionManager(boolean isCloudCollection) Create a reduction manager to manage the collection of all expressions that have been created since startGrouping() was called.
ReductionCollectionManager	createReductionManager(boolean isCloudCollection) Create a reduction manager to manage the collection of all expressions that have been created since startRequest() was called.
IndexSchema	getSchema() Get the index schema used by this factory.
void	startGrouping() Prepare the factory to start building the next grouping.
void	startRequest() Prepare the factory to start building the request.

Methods inherited from class java.lang.Object

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

Field Detail

variableLengthParamSuffix

public static final String variableLengthParamSuffix

Used to denote a variable length parameter.

See Also:

Constant Field Values

variableForEachSep

public static final char variableForEachSep

The character used to denote the start of a for each lambda expression

See Also:

Constant Field Values

variableForEachParam

public static final char variableForEachParam

The character used to denote the looped parameter in the for each lambda expression

See Also:

Constant Field Values

Constructor Detail

ExpressionFactory

public ExpressionFactory(IndexSchema schema)

Method Detail

getSchema

public IndexSchema getSchema()

Get the index schema used by this factory.

Returns:

the index schema

startRequest

public void startRequest()

Prepare the factory to start building the request.

startGrouping

public void startGrouping()

Prepare the factory to start building the next grouping.
NOTE: MUST be called before each new grouping.

addSystemFunction

public ExpressionFactory addSystemFunction(String functionName,
                                           ExpressionFactory.CreatorFunction functionCreator)
                                    throws SolrException

Add a system function to the expression factory. This will be treated as a native function and not a variable function.

Parameters:

functionName - the unique name for the function

functionCreator - the creator function to generate an expression

Returns:

this factory, to easily chain function adds

Throws:

SolrException - if the functionName is not unique

addSystemVariableFunction

public ExpressionFactory addSystemVariableFunction(String functionName,
                                                   String functionParams,
                                                   String returnSignature)
                                            throws SolrException

Add a variable function that will be treated like a system function.

Parameters:

functionName - the function's name

functionParams - the comma separated and ordered parameters of the function (e.g. "a,b" )

returnSignature - the return signature of the variable function (e.g. div(sum(a,b),count(b)) )

Returns:

this factory, to easily chain function adds

Throws:

SolrException - if the name of the function is not unique or the syntax of either signature is incorrect

addUserDefinedVariableFunction

public ExpressionFactory addUserDefinedVariableFunction(String functionSignature,
                                                        String returnSignature)
                                                 throws SolrException

Add a variable function that was defined in an analytics request.

Parameters:

functionSignature - the function signature of the variable function (e.g. func(a,b) )

returnSignature - the return signature of the variable function (e.g. div(sum(a,b),count(b)) )

Returns:

this factory, to easily chain function adds

Throws:

SolrException - if the name of the function is not unique or the syntax of either signature is incorrect

createReductionManager

public ReductionCollectionManager createReductionManager(boolean isCloudCollection)

Create a reduction manager to manage the collection of all expressions that have been created since startRequest() was called.

Parameters:

isCloudCollection - whether the request is a distributed request

Returns:

a reduction manager

createGroupingReductionManager

public ReductionCollectionManager createGroupingReductionManager(boolean isCloudCollection)

Create a reduction manager to manage the collection of all expressions that have been created since startGrouping() was called.

Parameters:

isCloudCollection - whether the request is a distributed request

Returns:

a reduction manager

createExpression

public AnalyticsValueStream createExpression(String expressionStr)
                                      throws SolrException

Parse and build an expression from the given expression string.

Parameters:

expressionStr - string that represents the desired expression

Returns:

the object representation of the expression

Throws:

SolrException - if an error occurs while constructing the expression

addSystemFunctions

public void addSystemFunctions()

Add the natively supported functionality.