Package com.inductiveautomation.ignition.gateway.expressions

Class AbstractMultiLevelExpressionParseContext

java.lang.Object

com.inductiveautomation.ignition.gateway.expressions.AbstractMultiLevelExpressionParseContext

All Implemented Interfaces:

ExpressionParseContext

Direct Known Subclasses:

AlarmEventCollectionExpressionParseContext, BeanStyleExpressionParseContext, PropertyBasedExpressionParseContext, ReportDataExpressionParseContext, SubqueryExpressionParseContext

public abstract class AbstractMultiLevelExpressionParseContext
extends java.lang.Object
implements ExpressionParseContext

The foundation for an expression parse context that tries to create a reference, but then delegates if the reference isn't the type expected. Implemented in this way because ultimately a RuntimeException should be thrown if the reference can't be built. So, this implementation may not throw an error, but eventually one of the contexts up the chain will.

By default the base's function factory is used.

Constructor Summary

Constructors

Constructor	Description
AbstractMultiLevelExpressionParseContext(ExpressionParseContext base)

Method Summary

Modifier and Type	Method	Description
Expression	createBoundExpression(java.lang.String path)	Called to create expressions to represent bound elements, like:
protected FunctionFactory	getBaseFunctionFactory()	Sub classes do some strange things, this lets them get the base function factory
protected ExpressionParseContext	getDelegateParseContext()	Returns the parse context that this one delegates to on failure to create a bound expression
FunctionFactory	getFunctionFactory()
protected abstract Expression	tryCreateBoundExpression(java.lang.String path)	This function should create the expression if possible.

Methods inherited from class java.lang.Object

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

Constructor Detail

AbstractMultiLevelExpressionParseContext

public AbstractMultiLevelExpressionParseContext(ExpressionParseContext base)

Method Detail

getDelegateParseContext

protected ExpressionParseContext getDelegateParseContext()

Returns the parse context that this one delegates to on failure to create a bound expression

getFunctionFactory

public FunctionFactory getFunctionFactory()

Specified by:

getFunctionFactory in interface ExpressionParseContext

getBaseFunctionFactory

protected FunctionFactory getBaseFunctionFactory()

Sub classes do some strange things, this lets them get the base function factory

createBoundExpression

public Expression createBoundExpression(java.lang.String path)
                                 throws java.lang.RuntimeException

Description copied from interface: ExpressionParseContext

Called to create expressions to represent bound elements, like:

 { path.to.something }
 

Specified by:

createBoundExpression in interface ExpressionParseContext

Parameters:

path - the text content inside the braces.

Throws:

java.lang.RuntimeException - because the CUP parser doesn't have a throws on the function that calls this inside the parser

tryCreateBoundExpression

protected abstract Expression tryCreateBoundExpression(java.lang.String path)

This function should create the expression if possible. If not, it should return null instead of throwing the error, in which case the parent parse context will be tried.