de.hybris.platform.btg.condition

Interface ExpressionEvaluator

All Known Implementing Classes:

AbstractCollectionDistinctExpressionEvaluator, AbstractCollectionExpressionEvaluator, AbstractComparableExpressionEvaluator, AbstractExpressionEvaluator, BooleanExpressionEvaluator, CategoryCollectionExpressionEvaluator, CollectionExpressionEvaluator, CompositeExpressionEvaluator, ContentpageCollectionExpressionEvaluator, DateExpressionEvaluator, KeyValuePairCollectionExpressionEvaluator, MappedNumericEvaluator, NumericExpressionEvaluator, PlainCollectionExpressionEvaluator, PriceExpressionEvaluator, ProductCollectionExpressionEvaluator, RegExpCollectionExpressionEvaluator, ReverseCollectionExpressionEvaluator, StringExpressionEvaluator, UserAddressPostalCodeExpressionEvaluator

public interface ExpressionEvaluator

Evaluates a logical expression to true or false.

Needs at least an left operand and an operator (e.g. "xyz" isEmpty).
Another valid expression is a left operand, an operator and a right operand.(e.g. 10 lessThen 20).

Any other combination of operand and operator is not valid.

Method Summary

Modifier and Type	Method and Description
boolean	evaluate(Object leftOperand, String operator, Object rightOperand) Evaluates this expression.
Class	getLeftType() Returns the type which is expected for left operand.
Collection<String>	getSupportedOperators() Returns a Collection of supported Operators.
Collection<Class>	getSupportedRightTypes(String operator) Returns a Collection of types which are supported as right Operand.
boolean	isSupported(Class leftType, String operator, Class rightType) Returns true when type of left and right operand and the passed operator is supported.

Method Detail

getLeftType

Class getLeftType()

Returns the type which is expected for left operand.

Returns:

type for left operand

getSupportedRightTypes

Collection<Class> getSupportedRightTypes(String operator)

Returns a Collection of types which are supported as right Operand.

Returns 'null' when requested operator is not supported. Returns an empty Collection when operator is supported but does not allow a right operand. In any other case returns a Collection of types which are supported for passed operator.

Parameters:

operator - the operator which shall be applied

Returns:

Collection of supported types

getSupportedOperators

Collection<String> getSupportedOperators()

Returns a Collection of supported Operators. At least one Operator must be returned whenever a left Operand is available.

Returns:

Collection of supported operators

isSupported

boolean isSupported(Class leftType,
                    String operator,
                    Class rightType)

Returns true when type of left and right operand and the passed operator is supported. In other words: when expression can be evaluated successfully to true or false without errors.

Parameters:

leftType - type of left operand

operator - the operator

rightType - type of right operand

Returns:

true when an evaluation is possible

evaluate

boolean evaluate(Object leftOperand,
                 String operator,
                 Object rightOperand)

Evaluates this expression. When operands or operator are not supported a ExpressionEvaluationException is thrown. Returns true when expression evaluates to true, returns false otherwise.

Parameters:

leftOperand - value for left operand

operator - operator

rightOperand - value for right operand

Returns:

true when expression evaluates to true