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 EL property accessor that knows how to retrieve keys 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)	Can read any Environment, thus always returns true.
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)	Read-only: no-op.

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

Can read any Environment, thus always returns true.

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

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

Read-only: no-op.

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