Package org.springframework.expression.spel

Class ExpressionState

java.lang.Object

org.springframework.expression.spel.ExpressionState

public class ExpressionState
extends Object

ExpressionState is for maintaining per-expression-evaluation state: any changes to it are not seen by other expressions, but it gives a place to hold local variables and for component expressions in a compound expression to communicate state. This is in contrast to the EvaluationContext, which is shared amongst expression evaluations, and any changes to it will be seen by other expressions or any code that chooses to ask questions of the context.

It also acts as a place to define common utility routines that the various AST nodes might need.

Since:

3.0

Author:

Andy Clement, Juergen Hoeller, Sam Brannen

Constructor Summary

Constructors

Constructor	Description
ExpressionState(EvaluationContext context)
ExpressionState(EvaluationContext context, SpelParserConfiguration configuration)
ExpressionState(EvaluationContext context, TypedValue rootObject)
ExpressionState(EvaluationContext context, TypedValue rootObject, SpelParserConfiguration configuration)

Method Summary

Modifier and Type	Method	Description
TypedValue	assignVariable(String name, Supplier<TypedValue> valueSupplier)	Assign the value created by the specified Supplier to a named variable within the evaluation context.
Object	convertValue(Object value, TypeDescriptor targetTypeDescriptor)
Object	convertValue(TypedValue value, TypeDescriptor targetTypeDescriptor)
void	enterScope()	Enter a new scope with a new root context object and a new local variable scope.
void	enterScope(String name, Object value)	Deprecated, for removal: This API element is subject to removal in a future version. as of 6.2 with no replacement; to be removed in 7.0
void	enterScope(Map<String,Object> variables)	Deprecated, for removal: This API element is subject to removal in a future version. as of 6.2 with no replacement; to be removed in 7.0
void	exitScope()
Class<?>	findType(String type)
TypedValue	getActiveContextObject()	The active context object is what unqualified references to properties/etc are resolved against.
SpelParserConfiguration	getConfiguration()
EvaluationContext	getEvaluationContext()
List<PropertyAccessor>	getPropertyAccessors()
TypedValue	getRootContextObject()
TypedValue	getScopeRootContextObject()
TypeComparator	getTypeComparator()
TypeConverter	getTypeConverter()
Object	lookupLocalVariable(String name)	Deprecated, for removal: This API element is subject to removal in a future version. as of 6.2 with no replacement; to be removed in 7.0
TypedValue	lookupVariable(String name)	Look up a named global variable in the evaluation context.
TypedValue	operate(Operation op, Object left, Object right)
void	popActiveContextObject()
void	pushActiveContextObject(TypedValue obj)
void	setLocalVariable(String name, Object value)	Deprecated, for removal: This API element is subject to removal in a future version. as of 6.2 with no replacement; to be removed in 7.0
void	setVariable(String name, Object value)	Set a named variable in the evaluation context to a specified value.

Methods inherited from class java.lang.Object

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

Constructor Details

ExpressionState

public ExpressionState(EvaluationContext context)

ExpressionState

public ExpressionState(EvaluationContext context,
 SpelParserConfiguration configuration)

ExpressionState

public ExpressionState(EvaluationContext context,
 TypedValue rootObject)

ExpressionState

public ExpressionState(EvaluationContext context,
 TypedValue rootObject,
 SpelParserConfiguration configuration)

Method Details

getActiveContextObject

public TypedValue getActiveContextObject()

The active context object is what unqualified references to properties/etc are resolved against.

pushActiveContextObject

public void pushActiveContextObject(TypedValue obj)

popActiveContextObject

public void popActiveContextObject()

getRootContextObject

public TypedValue getRootContextObject()

getScopeRootContextObject

public TypedValue getScopeRootContextObject()

assignVariable

public TypedValue assignVariable(String name,
 Supplier<TypedValue> valueSupplier)

Assign the value created by the specified Supplier to a named variable within the evaluation context.

In contrast to setVariable(String, Object), this method should only be invoked to support assignment within an expression.

Parameters:

name - the name of the variable to assign

valueSupplier - the supplier of the value to be assigned to the variable

Returns:

a TypedValue wrapping the assigned value

Since:

5.2.24

See Also:

• EvaluationContext.assignVariable(String, Supplier)

setVariable

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

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

In contrast to assignVariable(String, Supplier), this method should only be invoked programmatically.

Parameters:

name - the name of the variable to set

value - the value to be placed in the variable

See Also:

• EvaluationContext.setVariable(String, Object)

lookupVariable

public TypedValue lookupVariable(String name)

Look up a named global variable in the evaluation context.

Parameters:

name - the name of the variable to look up

Returns:

a TypedValue containing the value of the variable, or TypedValue.NULL if the variable does not exist

See Also:

• assignVariable(String, Supplier)
• setVariable(String, Object)

getTypeComparator

public TypeComparator getTypeComparator()

findType

public Class<?> findType(String type)
                  throws EvaluationException

Throws:

EvaluationException

getTypeConverter

public TypeConverter getTypeConverter()

convertValue

public Object convertValue(Object value,
 TypeDescriptor targetTypeDescriptor)
                    throws EvaluationException

Throws:

EvaluationException

convertValue

@Nullable
public Object convertValue(TypedValue value,
 TypeDescriptor targetTypeDescriptor)
                    throws EvaluationException

Throws:

EvaluationException

enterScope

public void enterScope()

Enter a new scope with a new root context object and a new local variable scope.

enterScope

@Deprecated(since="6.2",
            forRemoval=true)
public void enterScope(String name,
 Object value)

Deprecated, for removal: This API element is subject to removal in a future version.

as of 6.2 with no replacement; to be removed in 7.0

Enter a new scope with a new root context object and a new local variable scope containing the supplied name/value pair.

Parameters:

name - the name of the local variable

value - the value of the local variable

enterScope

@Deprecated(since="6.2",
            forRemoval=true)
public void enterScope(@Nullable
 Map<String,Object> variables)

Deprecated, for removal: This API element is subject to removal in a future version.

as of 6.2 with no replacement; to be removed in 7.0

Enter a new scope with a new root context object and a new local variable scope containing the supplied name/value pairs.

Parameters:

variables - a map containing name/value pairs for local variables

exitScope

public void exitScope()

setLocalVariable

@Deprecated(since="6.2",
            forRemoval=true)
public void setLocalVariable(String name,
 Object value)

Deprecated, for removal: This API element is subject to removal in a future version.

as of 6.2 with no replacement; to be removed in 7.0

Set a local variable with the given name to the supplied value within the current scope.

If a local variable with the given name already exists, it will be overwritten.

Parameters:

name - the name of the local variable

value - the value of the local variable

lookupLocalVariable

@Deprecated(since="6.2",
            forRemoval=true)
@Nullable
public Object lookupLocalVariable(String name)

Deprecated, for removal: This API element is subject to removal in a future version.

as of 6.2 with no replacement; to be removed in 7.0

Look up the value of the local variable with the given name.

Parameters:

name - the name of the local variable

Returns:

the value of the local variable, or null if the variable does not exist in the current scope

operate

public TypedValue operate(Operation op,
 @Nullable
 Object left,
 @Nullable
 Object right)
                   throws EvaluationException

Throws:

EvaluationException

getPropertyAccessors

public List<PropertyAccessor> getPropertyAccessors()

getEvaluationContext

public EvaluationContext getEvaluationContext()

getConfiguration

public SpelParserConfiguration getConfiguration()