Class StandardEvaluationContext

java.lang.Object

org.springframework.expression.spel.support.StandardEvaluationContext

All Implemented Interfaces:

EvaluationContext

Direct Known Subclasses:

MethodBasedEvaluationContext

public class StandardEvaluationContext
extends Object
implements EvaluationContext

A powerful and highly configurable EvaluationContext implementation.

This context uses standard implementations of all applicable strategies, based on reflection to resolve properties, methods, and fields. Note, however, that you may need to manually configure a StandardTypeLocator with a specific ClassLoader to ensure that the SpEL expression parser is able to reliably locate user types. See setTypeLocator(TypeLocator) for details.

In addition to support for setting and looking up variables as defined in the EvaluationContext API, StandardEvaluationContext also provides support for registering and looking up functions. The registerFunction(...) methods provide a convenient way to register a function as a Method or a MethodHandle; however, a function can also be registered via setVariable(String, Object) or setVariables(Map). Since functions share a namespace with the variables in this evaluation context, care must be taken to ensure that function names and variable names do not overlap.

For a simpler, builder-style context variant for data-binding purposes, consider using SimpleEvaluationContext instead which allows for opting into several SpEL features as needed by specific use cases.

Since:

3.0

Author:

Andy Clement, Juergen Hoeller, Sam Brannen, Stephane Nicoll

See Also:

• SimpleEvaluationContext
• ReflectivePropertyAccessor
• ReflectiveConstructorResolver
• ReflectiveMethodResolver
• StandardTypeLocator
• StandardTypeConverter
• StandardTypeComparator
• StandardOperatorOverloader

Constructor Summary

Constructors

Constructor	Description
StandardEvaluationContext()	Create a StandardEvaluationContext with a null root object.
StandardEvaluationContext(@Nullable Object rootObject)	Create a StandardEvaluationContext with the given root object.

Method Summary

Modifier and Type	Method	Description
void	addConstructorResolver(ConstructorResolver constructorResolver)	Add the supplied constructor resolver to this evaluation context.
void	addIndexAccessor(IndexAccessor indexAccessor)	Add the supplied index accessor to this evaluation context.
void	addMethodResolver(MethodResolver methodResolver)	Add the supplied method resolver to this evaluation context.
void	addPropertyAccessor(PropertyAccessor propertyAccessor)	Add the supplied property accessor to this evaluation context.
void	applyDelegatesTo(StandardEvaluationContext evaluationContext)	Apply the internal delegates of this instance to the specified evaluationContext.
@Nullable BeanResolver	getBeanResolver()	Get the configured BeanResolver for looking up beans, if any.
List<ConstructorResolver>	getConstructorResolvers()	Get the list of constructor resolvers to use in this evaluation context.
List<IndexAccessor>	getIndexAccessors()	Get the list of index accessors configured in this evaluation context.
List<MethodResolver>	getMethodResolvers()	Get the list of method resolvers to use in this evaluation context.
OperatorOverloader	getOperatorOverloader()	Get the configured OperatorOverloader for mathematical operations.
List<PropertyAccessor>	getPropertyAccessors()	Get the list of property accessors configured in this evaluation context.
TypedValue	getRootObject()	Return the configured default root context object against which unqualified properties, methods, etc.
TypeComparator	getTypeComparator()	Get the configured TypeComparator for comparing pairs of objects.
TypeConverter	getTypeConverter()	Get the configured TypeConverter for value conversion.
TypeLocator	getTypeLocator()	Get the configured TypeLocator that will be used to find types, either by short or fully-qualified name.
@Nullable Object	lookupVariable(String name)	Look up a named variable or function within this evaluation context.
void	registerFunction(String name, MethodHandle methodHandle)	Register the specified MethodHandle as a SpEL function.
void	registerFunction(String name, Method method)	Register the specified Method as a SpEL function.
void	registerMethodFilter(Class<?> type, MethodFilter filter)	Register a MethodFilter which will be called during method resolution for the specified type.
boolean	removeConstructorResolver(ConstructorResolver constructorResolver)	Remove the supplied constructor resolver from this evaluation context.
boolean	removeIndexAccessor(IndexAccessor indexAccessor)	Remove the supplied index accessor from this evaluation context.
boolean	removeMethodResolver(MethodResolver methodResolver)	Remove the supplied method resolver from this evaluation context.
boolean	removePropertyAccessor(PropertyAccessor propertyAccessor)	Remove the supplied property accessor from this evaluation context.
void	setBeanResolver(@Nullable BeanResolver beanResolver)	Set the BeanResolver to use for looking up beans, if any.
void	setConstructorResolvers(List<ConstructorResolver> constructorResolvers)	Set the list of constructor resolvers to use in this evaluation context.
void	setIndexAccessors(List<IndexAccessor> indexAccessors)	Set the list of index accessors to use in this evaluation context.
void	setMethodResolvers(List<MethodResolver> methodResolvers)	Set the list of method resolvers to use in this evaluation context.
void	setOperatorOverloader(OperatorOverloader operatorOverloader)	Set the OperatorOverloader for mathematical operations.
void	setPropertyAccessors(List<PropertyAccessor> propertyAccessors)	Set the list of property accessors to use in this evaluation context.
void	setRootObject(@Nullable Object rootObject)	Specify the default root context object against which unqualified properties, methods, etc.
void	setRootObject(@Nullable Object rootObject, TypeDescriptor typeDescriptor)	Specify the default root context object (including a type descriptor) against which unqualified properties, methods, etc.
void	setTypeComparator(TypeComparator typeComparator)	Set the TypeComparator for comparing pairs of objects.
void	setTypeConverter(TypeConverter typeConverter)	Set the TypeConverter for value conversion.
void	setTypeLocator(TypeLocator typeLocator)	Set the TypeLocator to use to find types, either by short or fully-qualified name.
void	setVariable(@Nullable String name, @Nullable Object value)	Set a named variable in this evaluation context to a specified value.
void	setVariables(Map<String,Object> variables)	Set multiple named variables in this evaluation context to the specified values.

Methods inherited from class Object

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

Methods inherited from interface EvaluationContext

assignVariable, isAssignmentEnabled

Constructor Details

StandardEvaluationContext

public StandardEvaluationContext()

Create a StandardEvaluationContext with a null root object.

StandardEvaluationContext

public StandardEvaluationContext(@Nullable Object rootObject)

Create a StandardEvaluationContext with the given root object.

Parameters:

rootObject - the root object to use

See Also:

• setRootObject(Object, TypeDescriptor)

Method Details

setRootObject

public void setRootObject(@Nullable Object rootObject,
 TypeDescriptor typeDescriptor)

Specify the default root context object (including a type descriptor) against which unqualified properties, methods, etc. should be resolved.

Parameters:

rootObject - the root object to use

typeDescriptor - a corresponding type descriptor

setRootObject

public void setRootObject(@Nullable Object rootObject)

Specify the default root context object against which unqualified properties, methods, etc. should be resolved.

Parameters:

rootObject - the root object to use

getRootObject

public TypedValue getRootObject()

Return the configured default root context object against which unqualified properties, methods, etc. should be resolved (can be TypedValue.NULL).

Specified by:

getRootObject in interface EvaluationContext

setPropertyAccessors

public void setPropertyAccessors(List<PropertyAccessor> propertyAccessors)

Set the list of property accessors to use in this evaluation context.

Replaces any previously configured property accessors.

getPropertyAccessors

public List<PropertyAccessor> getPropertyAccessors()

Get the list of property accessors configured in this evaluation context.

Specified by:

getPropertyAccessors in interface EvaluationContext

addPropertyAccessor

public void addPropertyAccessor(PropertyAccessor propertyAccessor)

Add the supplied property accessor to this evaluation context.

Parameters:

propertyAccessor - the property accessor to add

See Also:

• getPropertyAccessors()
• setPropertyAccessors(List)
• removePropertyAccessor(PropertyAccessor)

removePropertyAccessor

public boolean removePropertyAccessor(PropertyAccessor propertyAccessor)

Remove the supplied property accessor from this evaluation context.

Parameters:

propertyAccessor - the property accessor to remove

Returns:

true if the property accessor was removed, false if the property accessor was not configured in this evaluation context

See Also:

• getPropertyAccessors()
• setPropertyAccessors(List)
• addPropertyAccessor(PropertyAccessor)

setIndexAccessors

public void setIndexAccessors(List<IndexAccessor> indexAccessors)

Set the list of index accessors to use in this evaluation context.

Replaces any previously configured index accessors.

Since:

6.2

See Also:

• getIndexAccessors()
• addIndexAccessor(IndexAccessor)
• removeIndexAccessor(IndexAccessor)

getIndexAccessors

public List<IndexAccessor> getIndexAccessors()

Get the list of index accessors configured in this evaluation context.

Specified by:

getIndexAccessors in interface EvaluationContext

Since:

6.2

See Also:

• setIndexAccessors(List)
• addIndexAccessor(IndexAccessor)
• removeIndexAccessor(IndexAccessor)

addIndexAccessor

public void addIndexAccessor(IndexAccessor indexAccessor)

Add the supplied index accessor to this evaluation context.

Parameters:

indexAccessor - the index accessor to add

Since:

6.2

See Also:

• getIndexAccessors()
• setIndexAccessors(List)
• removeIndexAccessor(IndexAccessor)

removeIndexAccessor

public boolean removeIndexAccessor(IndexAccessor indexAccessor)

Remove the supplied index accessor from this evaluation context.

Parameters:

indexAccessor - the index accessor to remove

Returns:

true if the index accessor was removed, false if the index accessor was not configured in this evaluation context

Since:

6.2

See Also:

• getIndexAccessors()
• setIndexAccessors(List)
• addIndexAccessor(IndexAccessor)

setConstructorResolvers

public void setConstructorResolvers(List<ConstructorResolver> constructorResolvers)

Set the list of constructor resolvers to use in this evaluation context.

Replaces any previously configured constructor resolvers.

getConstructorResolvers

public List<ConstructorResolver> getConstructorResolvers()

Get the list of constructor resolvers to use in this evaluation context.

Specified by:

getConstructorResolvers in interface EvaluationContext

addConstructorResolver

public void addConstructorResolver(ConstructorResolver constructorResolver)

Add the supplied constructor resolver to this evaluation context.

Parameters:

constructorResolver - the constructor resolver to add

See Also:

• getConstructorResolvers()
• setConstructorResolvers(List)
• removeConstructorResolver(ConstructorResolver)

removeConstructorResolver

public boolean removeConstructorResolver(ConstructorResolver constructorResolver)

Remove the supplied constructor resolver from this evaluation context.

Parameters:

constructorResolver - the constructor resolver to remove

Returns:

true if the constructor resolver was removed, false if the constructor resolver was not configured in this evaluation context

See Also:

• getConstructorResolvers()
• setConstructorResolvers(List)
• addConstructorResolver(ConstructorResolver)

setMethodResolvers

public void setMethodResolvers(List<MethodResolver> methodResolvers)

Set the list of method resolvers to use in this evaluation context.

Replaces any previously configured method resolvers.

getMethodResolvers

public List<MethodResolver> getMethodResolvers()

Get the list of method resolvers to use in this evaluation context.

Specified by:

getMethodResolvers in interface EvaluationContext

addMethodResolver

public void addMethodResolver(MethodResolver methodResolver)

Add the supplied method resolver to this evaluation context.

Parameters:

methodResolver - the method resolver to add

See Also:

• getMethodResolvers()
• setMethodResolvers(List)
• removeMethodResolver(MethodResolver)

removeMethodResolver

public boolean removeMethodResolver(MethodResolver methodResolver)

Remove the supplied method resolver from this evaluation context.

Parameters:

methodResolver - the method resolver to remove

Returns:

true if the method resolver was removed, false if the method resolver was not configured in this evaluation context

See Also:

• getMethodResolvers()
• setMethodResolvers(List)
• addMethodResolver(MethodResolver)

setBeanResolver

public void setBeanResolver(@Nullable BeanResolver beanResolver)

Set the BeanResolver to use for looking up beans, if any.

getBeanResolver

public @Nullable BeanResolver getBeanResolver()

Get the configured BeanResolver for looking up beans, if any.

Specified by:

getBeanResolver in interface EvaluationContext

setTypeLocator

public void setTypeLocator(TypeLocator typeLocator)

Set the TypeLocator to use to find types, either by short or fully-qualified name.

By default, a StandardTypeLocator will be used.

NOTE: Even if a StandardTypeLocator is sufficient, you may need to manually configure a StandardTypeLocator with a specific ClassLoader to ensure that the SpEL expression parser is able to reliably locate user types.

Parameters:

typeLocator - the TypeLocator to use

See Also:

• StandardTypeLocator(ClassLoader)
• getTypeLocator()

getTypeLocator

public TypeLocator getTypeLocator()

Get the configured TypeLocator that will be used to find types, either by short or fully-qualified name.

See setTypeLocator(TypeLocator) for further details.

Specified by:

getTypeLocator in interface EvaluationContext

See Also:

• setTypeLocator(TypeLocator)

setTypeConverter

public void setTypeConverter(TypeConverter typeConverter)

Set the TypeConverter for value conversion.

getTypeConverter

public TypeConverter getTypeConverter()

Get the configured TypeConverter for value conversion.

Specified by:

getTypeConverter in interface EvaluationContext

setTypeComparator

public void setTypeComparator(TypeComparator typeComparator)

Set the TypeComparator for comparing pairs of objects.

getTypeComparator

public TypeComparator getTypeComparator()

Get the configured TypeComparator for comparing pairs of objects.

Specified by:

getTypeComparator in interface EvaluationContext

setOperatorOverloader

public void setOperatorOverloader(OperatorOverloader operatorOverloader)

Set the OperatorOverloader for mathematical operations.

getOperatorOverloader

public OperatorOverloader getOperatorOverloader()

Get the configured OperatorOverloader for mathematical operations.

Specified by:

getOperatorOverloader in interface EvaluationContext

setVariable

public void setVariable(@Nullable String name,
 @Nullable Object value)

Set a named variable in this evaluation context to a specified value.

If the specified name is null, it will be ignored. If the specified value is null, the named variable will be removed from this evaluation context.

In contrast to EvaluationContext.assignVariable(String,java.util.function.Supplier), this method should only be invoked programmatically when interacting directly with the EvaluationContext — for example, to provide initial configuration for the context.

Note that variables and functions share a common namespace in this evaluation context. See the class-level documentation for details.

Specified by:

setVariable in interface EvaluationContext

Parameters:

name - the name of the variable to set

value - the value to be placed in the variable

See Also:

• setVariables(Map)
• registerFunction(String, Method)
• registerFunction(String, MethodHandle)
• lookupVariable(String)

setVariables

public void setVariables(Map<String,Object> variables)

Set multiple named variables in this evaluation context to the specified values.

This is a convenience variant of setVariable(String, Object).

Note that variables and functions share a common namespace in this evaluation context. See the class-level documentation for details.

Parameters:

variables - the names and values of the variables to set

See Also:

• setVariable(String, Object)

registerFunction

public void registerFunction(String name,
 Method method)

Register the specified Method as a SpEL function.

Note that variables and functions share a common namespace in this evaluation context. See the class-level documentation for details.

Parameters:

name - the name of the function

method - the Method to register

See Also:

• registerFunction(String, MethodHandle)

registerFunction

public void registerFunction(String name,
 MethodHandle methodHandle)

Register the specified MethodHandle as a SpEL function.

Note that variables and functions share a common namespace in this evaluation context. See the class-level documentation for details.

Parameters:

name - the name of the function

methodHandle - the MethodHandle to register

Since:

6.1

See Also:

• registerFunction(String, Method)

lookupVariable

public @Nullable Object lookupVariable(String name)

Look up a named variable or function within this evaluation context.

Note that variables and functions share a common namespace in this evaluation context. See the class-level documentation for details.

Specified by:

lookupVariable in interface EvaluationContext

Parameters:

name - the name of the variable or function to look up

Returns:

the value of the variable or function, or null if not found

registerMethodFilter

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

Register a MethodFilter which will be called during method resolution for the specified type.

The MethodFilter may remove methods and/or sort the methods which will then be used by SpEL as the candidates to look through for a match.

Parameters:

type - the type for which the filter should be called

filter - a MethodFilter, or null to unregister a filter for the type

Throws:

IllegalStateException - if the ReflectiveMethodResolver is not in use

applyDelegatesTo

public void applyDelegatesTo(StandardEvaluationContext evaluationContext)

Apply the internal delegates of this instance to the specified evaluationContext. Typically invoked right after the new context instance has been created to reuse the delegates. Does not modify the root object or any registered variables or functions.

Parameters:

evaluationContext - the evaluation context to update

Since:

6.1.1