net.sf.morph.lang
Interface Language

All Known Subinterfaces:

DecoratedLanguage

All Known Implementing Classes:

BaseLanguage, LanguageDecorator, SimpleLanguage

public interface Language

Defines a syntax for expressions that can be used to access and change properties (bean or indexed) inside a target object. This is similar to the expression languages found in the JSTL EL, the Spring framework, Struts, and Velocity. Below are some example expressions.

JSTL EL example:
myBean.myMap.myProperty

Spring example:
myBean.myMap["myProperty"]

Since:

Nov 14, 2004

Author:

Matt Sgarlata

Method Summary

java.lang.Object	get(java.lang.Object target, java.lang.String expression) Retrieve the property indicated by expression from target.
java.lang.Class	getType(java.lang.Object target, java.lang.String expression) Specifies the least restrictive type that may be assigned to property indicated by the given expression.
boolean	isProperty(java.lang.String expression) Indicates whether the given expression refers to a direct property of a target object.
void	set(java.lang.Object target, java.lang.String expression, java.lang.Object value) Sets the property indicated by expression on target.

Method Detail

getType

java.lang.Class getType(java.lang.Object target,
                        java.lang.String expression)
                        throws LanguageException

Specifies the least restrictive type that may be assigned to property indicated by the given expression. If any type can be assigned to the property, this method returns Object.class.

Parameters:

target - the target being analyzed

expression - indicates the property of target that is to be analyzed

Returns:

the least restrictive type that may be assigned to the property identified by expression

Throws:

LanguageException - if target is null or
an error occurrs while evaluating an otherwise valid expression

InvalidExpressionException - if expression not a valid expression

isProperty

boolean isProperty(java.lang.String expression)
                   throws LanguageException

Indicates whether the given expression refers to a direct property of a target object.

Parameters:

expression - the expression to evaluate

Returns:

true, if the expression references a direct property of the target object or
false, otherwise

Throws:

LanguageException - an error occurrs while evaluating an otherwise valid expression

InvalidExpressionException - if expression not a valid expression

get

java.lang.Object get(java.lang.Object target,
                     java.lang.String expression)
                     throws LanguageException

Retrieve the property indicated by expression from target.

Parameters:

target - the object from which information will be retrieved

expression - an expression specifying which information to retrieve

Returns:

the information indicated by expression from target

Throws:

LanguageException - if target is null or
an error occurrs while evaluating an otherwise valid expression

InvalidExpressionException - if expression not a valid expression

set

void set(java.lang.Object target,
         java.lang.String expression,
         java.lang.Object value)
         throws LanguageException

Sets the property indicated by expression on target.

Parameters:

target - the object that will be modified

expression - an expression specifying which information will be modified

value - the information to be changed

Throws:

LanguageException - if target is null or
an error occurrs while evaluating an otherwise valid expression

InvalidExpressionException - if expression not a valid expression