org.springframework.expression.spel.support

Class ReflectivePropertyAccessor

java.lang.Object

org.springframework.expression.spel.support.ReflectivePropertyAccessor

All Implemented Interfaces:

PropertyAccessor

public class ReflectivePropertyAccessor
extends java.lang.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, Phillip Webb

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private static class	ReflectivePropertyAccessor.CacheKey
private static class	ReflectivePropertyAccessor.InvokerPair Captures the member (method/field) to call reflectively to access a property value and the type descriptor for the value returned by the reflective call.
private static class	ReflectivePropertyAccessor.OptimalPropertyAccessor An optimized form of a PropertyAccessor that will use reflection but only knows how to access a particular property on a particular class.

Field Summary

Fields

Modifier and Type	Field and Description
private java.util.Map<ReflectivePropertyAccessor.CacheKey,ReflectivePropertyAccessor.InvokerPair>	readerCache
private java.util.Map<ReflectivePropertyAccessor.CacheKey,TypeDescriptor>	typeDescriptorCache
private java.util.Map<ReflectivePropertyAccessor.CacheKey,java.lang.reflect.Member>	writerCache

Constructor Summary

Constructors

Constructor and Description
ReflectivePropertyAccessor()

Method Summary

Methods

Modifier and Type	Method and Description
boolean	canRead(EvaluationContext context, java.lang.Object target, java.lang.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, java.lang.Object target, java.lang.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, java.lang.Object target, java.lang.String name) Attempt to create an optimized property accessor tailored for a property of a particular name on a particular class.
protected java.lang.reflect.Field	findField(java.lang.String name, java.lang.Class<?> clazz, boolean mustBeStatic) Find a field of a certain name on a specified class
private java.lang.reflect.Field	findField(java.lang.String name, java.lang.Class<?> clazz, java.lang.Object target)
protected java.lang.reflect.Method	findGetterForProperty(java.lang.String propertyName, java.lang.Class<?> clazz, boolean mustBeStatic) Find a getter method for the specified property.
private java.lang.reflect.Method	findGetterForProperty(java.lang.String propertyName, java.lang.Class<?> clazz, java.lang.Object target)
protected java.lang.reflect.Method	findSetterForProperty(java.lang.String propertyName, java.lang.Class<?> clazz, boolean mustBeStatic) Find a setter method for the specified property.
private java.lang.reflect.Method	findSetterForProperty(java.lang.String propertyName, java.lang.Class<?> clazz, java.lang.Object target)
protected java.lang.String	getPropertyMethodSuffix(java.lang.String propertyName)
private java.lang.reflect.Method[]	getSortedClassMethods(java.lang.Class<?> clazz) Returns class methods ordered with non bridge methods appearing higher.
java.lang.Class<?>[]	getSpecificTargetClasses() Return an array of classes for which this resolver should be called.
private TypeDescriptor	getTypeDescriptor(EvaluationContext context, java.lang.Object target, java.lang.String name)
TypedValue	read(EvaluationContext context, java.lang.Object target, java.lang.String name) Called to read a property from a specified target object
void	write(EvaluationContext context, java.lang.Object target, java.lang.String name, java.lang.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

private final java.util.Map<ReflectivePropertyAccessor.CacheKey,ReflectivePropertyAccessor.InvokerPair> readerCache

writerCache

private final java.util.Map<ReflectivePropertyAccessor.CacheKey,java.lang.reflect.Member> writerCache

typeDescriptorCache

private final java.util.Map<ReflectivePropertyAccessor.CacheKey,TypeDescriptor> typeDescriptorCache

Constructor Detail

ReflectivePropertyAccessor

public ReflectivePropertyAccessor()

Method Detail

getSpecificTargetClasses

public java.lang.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,
              java.lang.Object target,
              java.lang.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,
              java.lang.Object target,
              java.lang.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,
               java.lang.Object target,
               java.lang.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,
         java.lang.Object target,
         java.lang.String name,
         java.lang.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

getTypeDescriptor

private TypeDescriptor getTypeDescriptor(EvaluationContext context,
                               java.lang.Object target,
                               java.lang.String name)

findGetterForProperty

private java.lang.reflect.Method findGetterForProperty(java.lang.String propertyName,
                                             java.lang.Class<?> clazz,
                                             java.lang.Object target)

findSetterForProperty

private java.lang.reflect.Method findSetterForProperty(java.lang.String propertyName,
                                             java.lang.Class<?> clazz,
                                             java.lang.Object target)

findField

private java.lang.reflect.Field findField(java.lang.String name,
                                java.lang.Class<?> clazz,
                                java.lang.Object target)

findGetterForProperty

protected java.lang.reflect.Method findGetterForProperty(java.lang.String propertyName,
                                             java.lang.Class<?> clazz,
                                             boolean mustBeStatic)

Find a getter method for the specified property.

findSetterForProperty

protected java.lang.reflect.Method findSetterForProperty(java.lang.String propertyName,
                                             java.lang.Class<?> clazz,
                                             boolean mustBeStatic)

Find a setter method for the specified property.

getSortedClassMethods

private java.lang.reflect.Method[] getSortedClassMethods(java.lang.Class<?> clazz)

Returns class methods ordered with non bridge methods appearing higher.

getPropertyMethodSuffix

protected java.lang.String getPropertyMethodSuffix(java.lang.String propertyName)

findField

protected java.lang.reflect.Field findField(java.lang.String name,
                                java.lang.Class<?> clazz,
                                boolean mustBeStatic)

Find a field of a certain name on a specified class

createOptimalAccessor

public PropertyAccessor createOptimalAccessor(EvaluationContext eContext,
                                     java.lang.Object target,
                                     java.lang.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.