de.unkrig.commons.text.expression

Interface Expression

All Known Implementing Classes:

AbstractExpression

public interface Expression

An expression evaluates to a value each time it is evaluated. If you want to evaluate an expression only once, you better use ExpressionEvaluator.evaluate(String, Mapping).

See Also:

Parser.parse()

Field Summary

Fields

Modifier and Type	Field and Description
static Expression	FALSE An expression which always evaluates to false.
static Expression	NULL An expression which always evaluates to null.
static Expression	TRUE An expression which always evaluates to true.

Method Summary

Modifier and Type	Method and Description
java.lang.Object	evaluate(Mapping<java.lang.String,?> variables) Computes the value of the expression
java.lang.Object	evaluateTo(Mapping<java.lang.String,?> variables, java.lang.Class<?> targetType)
boolean	evaluateToBoolean(Mapping<java.lang.String,?> variables)
java.lang.Object	evaluateToPrimitive(Mapping<java.lang.String,?> variables, java.lang.Class<?> targetType)

Field Detail

TRUE

static final Expression TRUE

An expression which always evaluates to true.

FALSE

static final Expression FALSE

An expression which always evaluates to false.

NULL

static final Expression NULL

An expression which always evaluates to null.

Method Detail

evaluate

@Nullable
java.lang.Object evaluate(Mapping<java.lang.String,?> variables)
                              throws EvaluationException

Computes the value of the expression

Parameters:

variables - The values of the variables that were named when the expression was parsed. Allowed values are String, Integer, Boolean, any other Object, or null.

Returns:

A String, Integer, Boolean, any other Object, or null

Throws:

EvaluationException - A problem occurred during evaluation, e.g. a class could not be loaded, or a type cast could not be performed

evaluateTo

@Nullable
java.lang.Object evaluateTo(Mapping<java.lang.String,?> variables,
                                       java.lang.Class<?> targetType)
                                throws EvaluationException

Throws:

EvaluationException

See Also:

AbstractExpression.evaluateTo(Mapping, Class)

evaluateToPrimitive

java.lang.Object evaluateToPrimitive(Mapping<java.lang.String,?> variables,
                                     java.lang.Class<?> targetType)
                              throws EvaluationException

Throws:

EvaluationException

See Also:

AbstractExpression.evaluateToPrimitive(Mapping, Class)

evaluateToBoolean

boolean evaluateToBoolean(Mapping<java.lang.String,?> variables)
                   throws EvaluationException

Throws:

EvaluationException

See Also:

AbstractExpression.evaluateToBoolean(Mapping)