org.springframework.context.expression

Class StandardBeanExpressionResolver

java.lang.Object

org.springframework.context.expression.StandardBeanExpressionResolver

All Implemented Interfaces:

BeanExpressionResolver

public class StandardBeanExpressionResolver
extends Object
implements BeanExpressionResolver

Standard implementation of the BeanExpressionResolver interface, parsing and evaluating Spring EL using Spring's expression module.

All beans in the containing BeanFactory are made available as predefined variables with their common bean name, including standard context beans such as "environment", "systemProperties" and "systemEnvironment".

Since:

3.0

Author:

Juergen Hoeller

See Also:

BeanExpressionContext.getBeanFactory(), ExpressionParser, SpelExpressionParser, StandardEvaluationContext

Field Summary

Fields

Modifier and Type	Field and Description
static String	DEFAULT_EXPRESSION_PREFIX Default expression prefix: "#{".
static String	DEFAULT_EXPRESSION_SUFFIX Default expression suffix: "}".

Constructor Summary

Constructors

Constructor and Description
StandardBeanExpressionResolver() Create a new StandardBeanExpressionResolver with default settings.
StandardBeanExpressionResolver(ClassLoader beanClassLoader) Create a new StandardBeanExpressionResolver with the given bean class loader, using it as the basis for expression compilation.

Method Summary

Modifier and Type	Method and Description
protected void	customizeEvaluationContext(StandardEvaluationContext evalContext) Template method for customizing the expression evaluation context.
Object	evaluate(String value, BeanExpressionContext beanExpressionContext) Evaluate the given value as an expression, if applicable; return the value as-is otherwise.
void	setExpressionParser(ExpressionParser expressionParser) Specify the EL parser to use for expression parsing.
void	setExpressionPrefix(String expressionPrefix) Set the prefix that an expression string starts with.
void	setExpressionSuffix(String expressionSuffix) Set the suffix that an expression string ends with.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

DEFAULT_EXPRESSION_PREFIX

public static final String DEFAULT_EXPRESSION_PREFIX

Default expression prefix: "#{".

See Also:

Constant Field Values

DEFAULT_EXPRESSION_SUFFIX

public static final String DEFAULT_EXPRESSION_SUFFIX

Default expression suffix: "}".

See Also:

Constant Field Values

Constructor Detail

StandardBeanExpressionResolver

public StandardBeanExpressionResolver()

Create a new StandardBeanExpressionResolver with default settings.

StandardBeanExpressionResolver

public StandardBeanExpressionResolver(@Nullable
                                      ClassLoader beanClassLoader)

Create a new StandardBeanExpressionResolver with the given bean class loader, using it as the basis for expression compilation.

Parameters:

beanClassLoader - the factory's bean class loader

Method Detail

setExpressionPrefix

public void setExpressionPrefix(String expressionPrefix)

Set the prefix that an expression string starts with. The default is "#{".

See Also:

DEFAULT_EXPRESSION_PREFIX

setExpressionSuffix

public void setExpressionSuffix(String expressionSuffix)

Set the suffix that an expression string ends with. The default is "}".

See Also:

DEFAULT_EXPRESSION_SUFFIX

setExpressionParser

public void setExpressionParser(ExpressionParser expressionParser)

Specify the EL parser to use for expression parsing.

Default is a SpelExpressionParser, compatible with standard Unified EL style expression syntax.

evaluate

@Nullable
public Object evaluate(@Nullable
                                 String value,
                                 BeanExpressionContext beanExpressionContext)
                          throws BeansException

Description copied from interface: BeanExpressionResolver

Evaluate the given value as an expression, if applicable; return the value as-is otherwise.

Specified by:

evaluate in interface BeanExpressionResolver

Parameters:

value - the value to evaluate as an expression

beanExpressionContext - the bean expression context to use when evaluating the expression

Returns:

the resolved value (potentially the given value as-is)

Throws:

BeansException - if evaluation failed

customizeEvaluationContext

protected void customizeEvaluationContext(StandardEvaluationContext evalContext)

Template method for customizing the expression evaluation context.

The default implementation is empty.