org.springframework.expression.spel.support

Class ReflectiveMethodResolver

java.lang.Object

org.springframework.expression.spel.support.ReflectiveMethodResolver

All Implemented Interfaces:

MethodResolver

Direct Known Subclasses:

DataBindingMethodResolver

public class ReflectiveMethodResolver
extends Object
implements MethodResolver

Reflection-based MethodResolver used by default in StandardEvaluationContext unless explicit method resolvers have been specified.

Since:

3.0

Author:

Andy Clement, Juergen Hoeller, Chris Beams

See Also:

StandardEvaluationContext.addMethodResolver(MethodResolver)

Constructor Summary

Constructors

Constructor and Description
ReflectiveMethodResolver()
ReflectiveMethodResolver(boolean useDistance) This constructor allows the ReflectiveMethodResolver to be configured such that it will use a distance computation to check which is the better of two close matches (when there are multiple matches).

Method Summary

Modifier and Type	Method and Description
protected Method[]	getMethods(Class<?> type) Return the set of methods for this type.
protected boolean	isCandidateForInvocation(Method method, Class<?> targetClass) Determine whether the given Method is a candidate for method resolution on an instance of the given target class.
void	registerMethodFilter(Class<?> type, MethodFilter filter) Register a filter for methods on the given type.
MethodExecutor	resolve(EvaluationContext context, Object targetObject, String name, List<TypeDescriptor> argumentTypes) Locate a method on a type.

Methods inherited from class java.lang.Object

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

Constructor Detail

ReflectiveMethodResolver

public ReflectiveMethodResolver()

ReflectiveMethodResolver

public ReflectiveMethodResolver(boolean useDistance)

This constructor allows the ReflectiveMethodResolver to be configured such that it will use a distance computation to check which is the better of two close matches (when there are multiple matches). Using the distance computation is intended to ensure matches are more closely representative of what a Java compiler would do when taking into account boxing/unboxing and whether the method candidates are declared to handle a supertype of the type (of the argument) being passed in.

Parameters:

useDistance - true if distance computation should be used when calculating matches; false otherwise

Method Detail

registerMethodFilter

public void registerMethodFilter(Class<?> type,
                                 MethodFilter filter)

Register a filter for methods on the given type.

Parameters:

type - the type to filter on

filter - the corresponding method filter, or null to clear any filter for the given type

resolve

public MethodExecutor resolve(EvaluationContext context,
                              Object targetObject,
                              String name,
                              List<TypeDescriptor> argumentTypes)
                       throws AccessException

Locate a method on a type. There are three kinds of match that might occur:

1. an exact match where the types of the arguments match the types of the constructor
2. an in-exact match where the types we are looking for are subtypes of those defined on the constructor
3. a match where we are able to convert the arguments into those expected by the constructor, according to the registered type converter

Specified by:

resolve in interface MethodResolver

Parameters:

context - the current evaluation context

targetObject - the object upon which the method is being called

argumentTypes - the arguments that the constructor must be able to handle

Returns:

a MethodExecutor that can invoke the method, or null if the method cannot be found

Throws:

AccessException

getMethods

protected Method[] getMethods(Class<?> type)

Return the set of methods for this type. The default implementation returns the result of Class.getMethods() for the given type, but subclasses may override in order to alter the results, e.g. specifying static methods declared elsewhere.

Parameters:

type - the class for which to return the methods

Since:

3.1.1

isCandidateForInvocation

protected boolean isCandidateForInvocation(Method method,
                                           Class<?> targetClass)

Determine whether the given Method is a candidate for method resolution on an instance of the given target class.

The default implementation considers any method as a candidate, even for static methods sand non-user-declared methods on the Object base class.

Parameters:

method - the Method to evaluate

targetClass - the concrete target class that is being introspected

Since:

4.3.15