程序包 cn.taketoday.expression.spel

类 ExpressionState

java.lang.Object

cn.taketoday.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.

从以下版本开始:

4.0

作者:

Andy Clement, Juergen Hoeller, Harry Yang

嵌套类概要

嵌套类

修饰符和类型	类	说明
private static class	ExpressionState.VariableScope	A new scope is entered when a function is called and it is used to hold the parameters to the function call.

字段概要

字段

修饰符和类型	字段	说明
private final SpelParserConfiguration	configuration
private Deque<TypedValue>	contextObjects
private final EvaluationContext	relatedContext
private final TypedValue	rootObject
private ArrayDeque<TypedValue>	scopeRootObjects
private Deque<ExpressionState.VariableScope>	variableScopes

构造器概要

构造器

构造器	说明
ExpressionState(EvaluationContext context)
ExpressionState(EvaluationContext context, SpelParserConfiguration configuration)
ExpressionState(EvaluationContext context, TypedValue rootObject)
ExpressionState(EvaluationContext context, TypedValue rootObject, SpelParserConfiguration configuration)

方法概要

修饰符和类型	方法	说明
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(TypedValue value, TypeDescriptor targetTypeDescriptor)
Object	convertValue(Object value, TypeDescriptor targetTypeDescriptor)
void	enterScope()
void	enterScope(String name, Object value)
void	enterScope(Map<String,Object> argMap)
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()
private Deque<TypedValue>	initScopeRootObjects()
private Deque<ExpressionState.VariableScope>	initVariableScopes()
Object	lookupLocalVariable(String name)
TypedValue	lookupVariable(String name)
TypedValue	operate(Operation op, Object left, Object right)
void	popActiveContextObject()
void	pushActiveContextObject(TypedValue obj)
void	setLocalVariable(String name, Object value)
void	setVariable(String name, Object value)	Set a named variable in the evaluation context to a specified value.

从类继承的方法 java.lang.Object

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

字段详细资料

relatedContext

private final EvaluationContext relatedContext

rootObject

private final TypedValue rootObject

configuration

private final SpelParserConfiguration configuration

contextObjects

@Nullable
private Deque<TypedValue> contextObjects

variableScopes

@Nullable
private Deque<ExpressionState.VariableScope> variableScopes

scopeRootObjects

@Nullable
private ArrayDeque<TypedValue> scopeRootObjects

构造器详细资料

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)

方法详细资料

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.

参数:

name - the name of the variable to assign

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

返回:

a TypedValue wrapping the assigned value

另请参阅:

• 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.

参数:

name - the name of the variable to set

value - the value to be placed in the variable

另请参阅:

• EvaluationContext.setVariable(String, Object)

lookupVariable

public TypedValue lookupVariable(String name)

getTypeComparator

public TypeComparator getTypeComparator()

findType

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

抛出:

EvaluationException

convertValue

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

抛出:

EvaluationException

getTypeConverter

public TypeConverter getTypeConverter()

convertValue

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

抛出:

EvaluationException

enterScope

public void enterScope(Map<String,Object> argMap)

enterScope

public void enterScope()

enterScope

public void enterScope(String name,
 Object value)

exitScope

public void exitScope()

setLocalVariable

public void setLocalVariable(String name,
 Object value)

lookupLocalVariable

@Nullable
public Object lookupLocalVariable(String name)

initVariableScopes

private Deque<ExpressionState.VariableScope> initVariableScopes()

initScopeRootObjects

private Deque<TypedValue> initScopeRootObjects()

operate

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

抛出:

EvaluationException

getPropertyAccessors

public List<PropertyAccessor> getPropertyAccessors()

getEvaluationContext

public EvaluationContext getEvaluationContext()

getConfiguration

public SpelParserConfiguration getConfiguration()