org.springframework.expression.spel.support
Class ReflectivePropertyAccessor

java.lang.Object
  org.springframework.expression.spel.support.ReflectivePropertyAccessor

All Implemented Interfaces:

PropertyAccessor

public class ReflectivePropertyAccessor
extends Object
implements PropertyAccessor

Simple PropertyAccessor that uses reflection to access properties for reading and writing. A property can be accessed if it is accessible as a field on the object or through a getter (if being read) or a setter (if being written).

Since:

3.0

Author:

Andy Clement, Juergen Hoeller

Field Summary

protected Map<org.springframework.expression.spel.support.ReflectivePropertyAccessor.CacheKey,org.springframework.expression.spel.support.ReflectivePropertyAccessor.InvokerPair>	readerCache
protected Map<org.springframework.expression.spel.support.ReflectivePropertyAccessor.CacheKey,TypeDescriptor>	typeDescriptorCache
protected Map<org.springframework.expression.spel.support.ReflectivePropertyAccessor.CacheKey,Member>	writerCache

Constructor Summary

ReflectivePropertyAccessor()

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.
PropertyAccessor	createOptimalAccessor(EvaluationContext eContext, Object target, String name) Attempt to create an optimized property accessor tailored for a property of a particular name on a particular class.
protected Field	findField(String name, Class<?> clazz, boolean mustBeStatic) Find a field of a certain name on a specified class
protected Method	findGetterForProperty(String propertyName, Class<?> clazz, boolean mustBeStatic) Find a getter method for the specified property.
protected Method	findSetterForProperty(String propertyName, Class<?> clazz, boolean mustBeStatic) Find a setter method for the specified property.
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

Field Detail

readerCache

protected final Map<org.springframework.expression.spel.support.ReflectivePropertyAccessor.CacheKey,org.springframework.expression.spel.support.ReflectivePropertyAccessor.InvokerPair> readerCache

writerCache

protected final Map<org.springframework.expression.spel.support.ReflectivePropertyAccessor.CacheKey,Member> writerCache

typeDescriptorCache

protected final Map<org.springframework.expression.spel.support.ReflectivePropertyAccessor.CacheKey,TypeDescriptor> typeDescriptorCache

Constructor Detail

ReflectivePropertyAccessor

public ReflectivePropertyAccessor()

Method Detail

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:

null which means this is a general purpose accessor

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

findGetterForProperty

protected Method findGetterForProperty(String propertyName,
                                       Class<?> clazz,
                                       boolean mustBeStatic)

Find a getter method for the specified property. A getter is defined as a method whose name start with the prefix 'get' and the rest of the name is the same as the property name (with the first character uppercased).

findSetterForProperty

protected Method findSetterForProperty(String propertyName,
                                       Class<?> clazz,
                                       boolean mustBeStatic)

Find a setter method for the specified property.

findField

protected Field findField(String name,
                          Class<?> clazz,
                          boolean mustBeStatic)

Find a field of a certain name on a specified class

createOptimalAccessor

public PropertyAccessor createOptimalAccessor(EvaluationContext eContext,
                                              Object target,
                                              String name)

Attempt to create an optimized property accessor tailored for a property of a particular name on a particular class. The general ReflectivePropertyAccessor will always work but is not optimal due to the need to lookup which reflective member (method/field) to use each time read() is called. This method will just return the ReflectivePropertyAccessor instance if it is unable to build something more optimal.