接口 PropertyAccessor
- 所有已知子接口:
CompilablePropertyAccessor
- 所有已知实现类:
BeanExpressionContextAccessor
,BeanFactoryAccessor
,DataBindingPropertyAccessor
,EnvironmentAccessor
,MapAccessor
,ReflectivePropertyAccessor
,ReflectivePropertyAccessor.OptimalPropertyAccessor
public interface PropertyAccessor
A property accessor is able to read from (and possibly write to) an object's properties. This interface places no restrictions, and so implementors are free to access properties directly as fields or through getters or in any other way they see as appropriate.A resolver can optionally specify an array of target classes for which it should be called. However, if it returns
null
fromgetSpecificTargetClasses()
, it will be called for all property references and given a chance to determine if it can read or write them.Property resolvers are considered to be ordered and each will be called in turn. The only rule that affects the call order is that any naming the target class directly in
getSpecificTargetClasses()
will be called first, before the general resolvers.- 从以下版本开始:
- 3.0
- 作者:
- Andy Clement
方法概要
所有方法 实例方法 抽象方法 修饰符和类型 方法 说明 boolean
canRead(EvaluationContext context, Object target, String name)
Called to determine if a resolver instance is able to access a specified property on a specified target object.boolean
canWrite(EvaluationContext context, Object target, String name)
Called to determine if a resolver instance is able to write to a specified property on a specified target object.Class<?>[]
getSpecificTargetClasses()
Return an array of classes for which this resolver should be called.TypedValue
read(EvaluationContext context, Object target, String name)
Called to read a property from a specified target object.void
write(EvaluationContext context, Object target, String name, Object newValue)
Called to write to a property on a specified target object.
方法详细资料
getSpecificTargetClasses
Class<?>[] getSpecificTargetClasses()
Return an array of classes for which this resolver should be called.>Returning
null
indicates this is a general resolver that can be called in an attempt to resolve a property on any type.- 返回:
- an array of classes that this resolver is suitable for (or
null
if a general resolver)
canRead
boolean canRead(EvaluationContext context, Object target, String name) throws AccessException
Called to determine if a resolver instance is able to access a specified property on a specified target object.- 参数:
context
- the evaluation context in which the access is being attemptedtarget
- the target object upon which the property is being accessedname
- the name of the property being accessed- 返回:
- true if this resolver is able to read the property
- 抛出:
AccessException
- if there is any problem determining whether the property can be read
read
TypedValue read(EvaluationContext context, Object target, String name) throws AccessException
Called to read a property from a specified target object. Should only succeed ifcanRead(org.springframework.expression.EvaluationContext, java.lang.Object, java.lang.String)
also returnstrue
.- 参数:
context
- the evaluation context in which the access is being attemptedtarget
- the target object upon which the property is being accessedname
- the name of the property being accessed- 返回:
- a TypedValue object wrapping the property value read and a type descriptor for it
- 抛出:
AccessException
- if there is any problem accessing the property value
canWrite
boolean canWrite(EvaluationContext context, Object target, String name) throws AccessException
Called to determine if a resolver instance is able to write to a specified property on a specified target object.- 参数:
context
- the evaluation context in which the access is being attemptedtarget
- the target object upon which the property is being accessedname
- the name of the property being accessed- 返回:
- true if this resolver is able to write to the property
- 抛出:
AccessException
- if there is any problem determining whether the property can be written to
write
void write(EvaluationContext context, Object target, String name, Object newValue) throws AccessException
Called to write to a property on a specified target object. Should only succeed ifcanWrite(org.springframework.expression.EvaluationContext, java.lang.Object, java.lang.String)
also returnstrue
.- 参数:
context
- the evaluation context in which the access is being attemptedtarget
- the target object upon which the property is being accessedname
- the name of the property being accessednewValue
- the new value for the property- 抛出:
AccessException
- if there is any problem writing to the property value