org.eth.cyril.expressions

Interface Expression

All Known Implementing Classes:

JavaFieldsExpression, JavaMethodExpression

public interface Expression

An expression can be evaluated to allow for their results to be visualized or otherwise further handled. Each expression returns a Value instance for further processing.

Method Summary

Modifier and Type	Method and Description
java.lang.String	describe(Value value, Value... args) Describe this expression in a human-readable way.
java.util.Optional<Value>	evaluate(Value value, Value... args) Evaluates the given expression for the given value and the array of arguments.
void	initialize(DrawingStepHandler stepHandler) Initialize the given step handler.
int	requiredArguments() Returns the number of required arguments to evaluate this expression.

Method Detail

requiredArguments

int requiredArguments()

Returns the number of required arguments to evaluate this expression.

evaluate

java.util.Optional<Value> evaluate(Value value,
                                   Value... args)

Evaluates the given expression for the given value and the array of arguments. The number of needed arguments depends on the expression, and in some cases no arguments may be supplied. See requiredArguments() for the number of required arguments to be supplied.

Parameters:

value - The value to evaluate the expression for.

args - The array of arguments. There must be at least requiredArguments() arguments given. Additional arguments will be ignored.

Returns:

A value representing the result of the evaluated expression. If any error occurs during evaluation, an empty optional is returned instead. Note that however supplying an insufficient number of arguments will instead throw an IllegalArgumentException.

Throws:

java.lang.IllegalArgumentException - If the number of arguments supplied is smaller than requiredArguments().

describe

java.lang.String describe(Value value,
                          Value... args)

Describe this expression in a human-readable way. This description is an already translated string. This expression should be described as if it were evaluated with the given value and arguments.

Parameters:

value - The value which would be given to the evaluate(Value, Value...) method.

args - The array of arguments which would be given to the evaluate(Value, Value...) method.

Returns:

A string describing this expression, if it were evaluated on the given arguments. Note that this string does not describe the result of the evaluation, but rather the operation behind it.

initialize

void initialize(DrawingStepHandler stepHandler)

Initialize the given step handler. The step handler will be used to layout the heaps produced by this expression. The expression initializes the step handler to be properly usable, for example by changing the DSLUpdater instance used for updates to the blacklist, etc.

Parameters:

stepHandler - The step handler to be initialized.