org.springframework.context.expression
Class MapAccessor

java.lang.Object
  org.springframework.context.expression.MapAccessor

All Implemented Interfaces:

PropertyAccessor

public class MapAccessor
extends Object
implements PropertyAccessor

EL property accessor that knows how to traverse the keys of a standard Map.

Since:

3.0

Author:

Juergen Hoeller, Andy Clement

Constructor Summary

MapAccessor()

Method Summary

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.

Methods inherited from class java.lang.Object

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

Constructor Detail

MapAccessor

public MapAccessor()

Method Detail

canRead

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

Description copied from interface: PropertyAccessor

Called to determine if a resolver instance is able to access 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 resolver 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,
                       Object target,
                       String name)
                throws AccessException

Description copied from interface: PropertyAccessor

Called to read a property from a specified target object

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 accessing the property value

canWrite

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

Description copied from interface: PropertyAccessor

Called to determine if a resolver instance is able to write to a specified property on a specified target object.

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 resolver 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,
                  Object target,
                  String name,
                  Object newValue)
           throws AccessException

Description copied from interface: PropertyAccessor

Called to write to a property on a specified target object. Should only succeed if canWrite() 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

getSpecificTargetClasses

public Class[] getSpecificTargetClasses()

Description copied from interface: PropertyAccessor

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.

Specified by:

getSpecificTargetClasses in interface PropertyAccessor

Returns:

an array of classes that this resolver is suitable for (or null if a general resolver)