Package org.springframework.context.expression

Class EnvironmentAccessor

java.lang.Object

org.springframework.context.expression.EnvironmentAccessor

All Implemented Interfaces:

PropertyAccessor, TargetedAccessor

public class EnvironmentAccessor
extends Object
implements PropertyAccessor

Read-only SpEL PropertyAccessor that knows how to retrieve properties of a Spring Environment instance.

Since:

3.1

Author:

Chris Beams

Constructor Summary

Constructors

Constructor	Description
EnvironmentAccessor()

Method Summary

Modifier and Type	Method	Description
boolean	canRead(EvaluationContext context, Object target, String name)	Called to determine if this property accessor is able to read a specified property on a specified target object.
boolean	canWrite(EvaluationContext context, Object target, String name)	Read-only: returns false.
Class<?>[]	getSpecificTargetClasses()	Get the set of classes for which this accessor should be called.
TypedValue	read(EvaluationContext context, Object target, String name)	Access the given target object by resolving the given property name against the given target environment.
void	write(EvaluationContext context, Object target, String name, Object newValue)	Called to write to a property on a specified target object.

Methods inherited from class java.lang.Object

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

Constructor Details

EnvironmentAccessor

public EnvironmentAccessor()

Method Details

getSpecificTargetClasses

public Class<?>[] getSpecificTargetClasses()

Description copied from interface: TargetedAccessor

Get the set of classes for which this accessor should be called.

Returning null or an empty array indicates this is a generic accessor that can be called in an attempt to access an element on any type.

Specified by:

getSpecificTargetClasses in interface TargetedAccessor

Returns:

an array of classes that this accessor is suitable for (or null or an empty array if a generic accessor)

canRead

public boolean canRead(EvaluationContext context,
 @Nullable
 Object target,
 String name)
                throws AccessException

Description copied from interface: PropertyAccessor

Called to determine if this property accessor is able to read a specified property on a specified target object.

Specified by:

canRead in interface PropertyAccessor

Parameters:

context - the evaluation context in which the access is being attempted

target - the target object upon which the property is being accessed

name - the name of the property being accessed

Returns:

true if this property accessor is able to read the property

Throws:

AccessException - if there is any problem determining whether the property can be read

read

public TypedValue read(EvaluationContext context,
 @Nullable
 Object target,
 String name)
                throws AccessException

Access the given target object by resolving the given property name against the given target environment.

Specified by:

read in interface PropertyAccessor

Parameters:

context - the evaluation context in which the access is being attempted

target - the target object upon which the property is being accessed

name - the name of the property being accessed

Returns:

a TypedValue object wrapping the property value read and a type descriptor for it

Throws:

AccessException - if there is any problem reading the property value

canWrite

public boolean canWrite(EvaluationContext context,
 @Nullable
 Object target,
 String name)
                 throws AccessException

Read-only: returns false.

Specified by:

canWrite in interface PropertyAccessor

Parameters:

context - the evaluation context in which the access is being attempted

target - the target object upon which the property is being accessed

name - the name of the property being accessed

Returns:

true if this property accessor is able to write to the property

Throws:

AccessException - if there is any problem determining whether the property can be written to

write

public void write(EvaluationContext context,
 @Nullable
 Object target,
 String name,
 @Nullable
 Object newValue)
           throws AccessException

Description copied from interface: PropertyAccessor

Called to write to a property on a specified target object.

Should only succeed if PropertyAccessor.canWrite(org.springframework.expression.EvaluationContext, java.lang.Object, java.lang.String) also returns true.

Specified by:

write in interface PropertyAccessor

Parameters:

context - the evaluation context in which the access is being attempted

target - the target object upon which the property is being accessed

name - the name of the property being accessed

newValue - the new value for the property

Throws:

AccessException - if there is any problem writing to the property value