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 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(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
FunctionFactory	getFunctionFactory()	Returns the function factory to be used for looking up functions during parsing.
protected abstract Expression	tryCreateBoundExpression(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 Details

AbstractMultiLevelExpressionParseContext

public AbstractMultiLevelExpressionParseContext(ExpressionParseContext base)

Method Details

getFunctionFactory

public FunctionFactory getFunctionFactory()

Description copied from interface: ExpressionParseContext

Returns the function factory to be used for looking up functions during parsing.

Specified by:

getFunctionFactory in interface ExpressionParseContext

Returns:

the FunctionFactory

getBaseFunctionFactory

protected FunctionFactory getBaseFunctionFactory()

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

createBoundExpression

public Expression createBoundExpression(String path)
                                 throws 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.

Returns:

the created Expression

Throws:

RuntimeException - if the expression cannot be created (e.g., invalid path)

tryCreateBoundExpression

protected abstract Expression tryCreateBoundExpression(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.