com.espertech.esper.view
Class ViewFactorySupport

java.lang.Object
  com.espertech.esper.view.ViewFactorySupport

All Implemented Interfaces:

ViewFactory

Direct Known Subclasses:

EventRowRegexNFAViewFactory

public abstract class ViewFactorySupport
extends java.lang.Object
implements ViewFactory

Abstract base class for view factories that do not make re-useable views and that do not share view resources with expression nodes.

Constructor Summary

ViewFactorySupport()

Method Summary

static void	assertReturnsNonConstant(java.lang.String viewName, ExprNode expression, int index) Assert and throws an exception if the expression passed returns a non-constant value.
boolean	canReuse(View view) Determines if the given view could be used instead of creating a new view, requires the view factory to compare view type, parameters and other capabilities provided.
static java.lang.Object	evaluateAssertNoProperties(java.lang.String viewName, ExprNode expression, int index, ExprEvaluatorContext exprEvaluatorContext) Assert and throws an exception if the expression uses event property values.
static java.lang.String	getViewParamMessageNumericOrTimePeriod(java.lang.String viewName)
static ExprNode[]	validate(java.lang.String viewName, EventType eventType, StatementContext statementContext, java.util.List<ExprNode> expressions, boolean allowConstantResult) Validate the view parameter expressions and return the validated expression for later execution.
static java.lang.Object	validateAndEvaluate(java.lang.String viewName, StatementContext statementContext, ExprNode expression) Validate the view parameter expression and evaluate the expression returning the result object.
static java.util.List<java.lang.Object>	validateAndEvaluate(java.lang.String viewName, StatementContext statementContext, java.util.List<ExprNode> expressions) Validate the view parameter expressions and evaluate the expressions returning the result object.
static java.lang.Object	validateAndEvaluateExpr(java.lang.String viewName, StatementContext statementContext, ExprNode expression, StreamTypeService streamTypeService, int expressionNumber)
static ExprNode	validateExpr(java.lang.String viewName, StatementContext statementContext, ExprNode expression, StreamTypeService streamTypeService, int expressionNumber)

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.espertech.esper.view.ViewFactory

attach, getEventType, getViewName, makeView, setViewParameters

Constructor Detail

ViewFactorySupport

public ViewFactorySupport()

Method Detail

canReuse

public boolean canReuse(View view)

Description copied from interface: ViewFactory

Determines if the given view could be used instead of creating a new view, requires the view factory to compare view type, parameters and other capabilities provided.

Specified by:

canReuse in interface ViewFactory

Parameters:

view - is the candidate view to compare to

Returns:

true if the given view can be reused instead of creating a new view, or false to indicate the view is not right for reuse

validateAndEvaluate

public static java.lang.Object validateAndEvaluate(java.lang.String viewName,
                                                   StatementContext statementContext,
                                                   ExprNode expression)
                                            throws ViewParameterException

Validate the view parameter expression and evaluate the expression returning the result object.

Parameters:

viewName - textual name of view

statementContext - context with statement services

expression - view expression parameter to validate

Returns:

object result value of parameter expression

Throws:

ViewParameterException - if the expressions fail to validate

validateAndEvaluate

public static java.util.List<java.lang.Object> validateAndEvaluate(java.lang.String viewName,
                                                                   StatementContext statementContext,
                                                                   java.util.List<ExprNode> expressions)
                                                            throws ViewParameterException

Validate the view parameter expressions and evaluate the expressions returning the result object.

Parameters:

viewName - textual name of view

statementContext - context with statement services

expressions - view expression parameter to validate

Returns:

object result value of parameter expressions

Throws:

ViewParameterException - if the expressions fail to validate

validate

public static ExprNode[] validate(java.lang.String viewName,
                                  EventType eventType,
                                  StatementContext statementContext,
                                  java.util.List<ExprNode> expressions,
                                  boolean allowConstantResult)
                           throws ViewParameterException

Validate the view parameter expressions and return the validated expression for later execution.

Does not evaluate the expression.

Parameters:

viewName - textual name of view

eventType - is the event type of the parent view or stream attached.

statementContext - context with statement services

expressions - view expression parameter to validate

allowConstantResult - true to indicate whether expressions that return a constant result should be allowed; false to indicate that if an expression is known to return a constant result the expression is considered invalid

Returns:

object result value of parameter expressions

Throws:

ViewParameterException - if the expressions fail to validate

assertReturnsNonConstant

public static void assertReturnsNonConstant(java.lang.String viewName,
                                            ExprNode expression,
                                            int index)
                                     throws ViewParameterException

Assert and throws an exception if the expression passed returns a non-constant value.

Parameters:

viewName - textual name of view

expression - expression to check

index - number offset of expression in view parameters

Throws:

ViewParameterException - if assertion fails

evaluateAssertNoProperties

public static java.lang.Object evaluateAssertNoProperties(java.lang.String viewName,
                                                          ExprNode expression,
                                                          int index,
                                                          ExprEvaluatorContext exprEvaluatorContext)
                                                   throws ViewParameterException

Assert and throws an exception if the expression uses event property values.

Parameters:

viewName - textual name of view

expression - expression to check

index - number offset of expression in view parameters

exprEvaluatorContext - context for expression evaluation

Returns:

expression evaluation value

Throws:

ViewParameterException - if assertion fails

validateAndEvaluateExpr

public static java.lang.Object validateAndEvaluateExpr(java.lang.String viewName,
                                                       StatementContext statementContext,
                                                       ExprNode expression,
                                                       StreamTypeService streamTypeService,
                                                       int expressionNumber)
                                                throws ViewParameterException

Throws:

ViewParameterException

validateExpr

public static ExprNode validateExpr(java.lang.String viewName,
                                    StatementContext statementContext,
                                    ExprNode expression,
                                    StreamTypeService streamTypeService,
                                    int expressionNumber)
                             throws ViewParameterException

Throws:

ViewParameterException

getViewParamMessageNumericOrTimePeriod

public static java.lang.String getViewParamMessageNumericOrTimePeriod(java.lang.String viewName)