org.apache.tapestry.services
Interface ExpressionEvaluator

All Known Implementing Classes:

ExpressionEvaluatorImpl

public interface ExpressionEvaluator

Wrapper around the OGNL library.

Since:

4.0

Author:

Howard M. Lewis Ship

Method Summary

boolean	isConstant(String expression) Returns true if the expression evaluates to a constant or other literal value.
Object	read(Object target, String expression) Reads a property of the target, defined by the expression.
Object	readCompiled(Object target, Object expression) Reads a property of the target, defined by the (previously compiled) expression.
void	write(Object target, String expression, Object value) Updates a property of the target, defined by the expression.
void	writeCompiled(Object target, Object expression, Object value) Updates a property of the target, defined by the (previously compiled) expression.

Method Detail

read

Object read(Object target,
            String expression)

Reads a property of the target, defined by the expression.

Throws:

ApplicationRuntimeException - if the expression can not be parsed, or if some other error occurs during evaluation of the expression.

readCompiled

Object readCompiled(Object target,
                    Object expression)

Reads a property of the target, defined by the (previously compiled) expression.

Throws:

ApplicationRuntimeException - if some other error occurs during evaluation of the expression.

write

void write(Object target,
           String expression,
           Object value)

Updates a property of the target, defined by the expression.

Throws:

ApplicationRuntimeException - if the expression can not be parsed, or if some other error occurs during evaluation of the expression.

writeCompiled

void writeCompiled(Object target,
                   Object expression,
                   Object value)

Updates a property of the target, defined by the (previously compiled) expression.

Throws:

ApplicationRuntimeException - if some other error occurs during evaluation of the expression.

isConstant

boolean isConstant(String expression)

Returns true if the expression evaluates to a constant or other literal value.

Throws:

ApplicationRuntimeException - if the expression is not valid