所有已知实现类:
Assign, BeanReference, BooleanLiteral, CompoundExpression, ConstructorReference, Elvis, FloatLiteral, FunctionReference, Identifier, Indexer, InlineList, InlineMap, IntLiteral, Literal, LongLiteral, MethodReference, NullLiteral, OpAnd, OpDec, OpDivide, OpEQ, Operator, OperatorBetween, OperatorInstanceof, OperatorMatches, OperatorNot, OperatorPower, OpGE, OpGT, OpInc, OpLE, OpLT, OpMinus, OpModulus, OpMultiply, OpNE, OpOr, OpPlus, Projection, PropertyOrFieldReference, QualifiedIdentifier, RealLiteral, Selection, SpelNodeImpl, StringLiteral, Ternary, TypeReference, VariableReference
```
public interface SpelNode
```
Represents a node in the Ast for a parsed expression.
从以下版本开始:
3.0
作者:
Andy Clement

方法概要

所有方法实例方法抽象方法
修饰符和类型	方法	说明
`SpelNode`	`getChild(int index)`	Helper method that returns a SpelNode rather than an Antlr Tree node.
`int`	`getChildCount()`
`int`	`getEndPosition()`
`Class<?>`	`getObjectClass(Object obj)`	Determine the class of the object passed in, unless it is already a class object.
`int`	`getStartPosition()`
`TypedValue`	`getTypedValue(ExpressionState expressionState)`	Evaluate the expression node in the context of the supplied expression state and return the typed value.
`Object`	`getValue(ExpressionState expressionState)`	Evaluate the expression node in the context of the supplied expression state and return the value.
`boolean`	`isWritable(ExpressionState expressionState)`	Determine if this expression node will support a setValue() call.
`void`	`setValue(ExpressionState expressionState, Object newValue)`	Evaluate the expression to a node and then set the new value on that node.
`String`	`toStringAST()`

- 方法详细资料
  - getValue
```
Object getValue(ExpressionState expressionState)
         throws EvaluationException
```
    Evaluate the expression node in the context of the supplied expression state and return the value.
    参数:
    expressionState - the current expression state (includes the context)
    返回:
    the value of this node evaluated against the specified state
    抛出:
    EvaluationException
  - getTypedValue
```
TypedValue getTypedValue(ExpressionState expressionState)
                  throws EvaluationException
```
    Evaluate the expression node in the context of the supplied expression state and return the typed value.
    参数:
    expressionState - the current expression state (includes the context)
    返回:
    the type value of this node evaluated against the specified state
    抛出:
    EvaluationException
  - isWritable
```
boolean isWritable(ExpressionState expressionState)
            throws EvaluationException
```
    Determine if this expression node will support a setValue() call.
    参数:
    expressionState - the current expression state (includes the context)
    返回:
    true if the expression node will allow setValue()
    抛出:
    EvaluationException - if something went wrong trying to determine if the node supports writing
  - setValue
```
void setValue(ExpressionState expressionState,
              Object newValue)
       throws EvaluationException
```
    Evaluate the expression to a node and then set the new value on that node. For example, if the expression evaluates to a property reference, then the property will be set to the new value.
    参数:
    expressionState - the current expression state (includes the context)
    newValue - the new value
    抛出:
    EvaluationException - if any problem occurs evaluating the expression or setting the new value
  - toStringAST
```
String toStringAST()
```
    返回:
    the string form of this AST node
  - getChildCount
```
int getChildCount()
```
    返回:
    the number of children under this node
  - getChild
```
SpelNode getChild(int index)
```
    Helper method that returns a SpelNode rather than an Antlr Tree node.
    返回:
    the child node cast to a SpelNode
  - getObjectClass
```
Class<?> getObjectClass(Object obj)
```
    Determine the class of the object passed in, unless it is already a class object.
    参数:
    obj - the object that the caller wants the class of
    返回:
    the class of the object if it is not already a class object, or null if the object is null
  - getStartPosition
```
int getStartPosition()
```
    返回:
    the start position of this Ast node in the expression string
  - getEndPosition
```
int getEndPosition()
```
    返回:
    the end position of this Ast node in the expression string

接口 SpelNode

方法概要

方法详细资料

getValue

getTypedValue

isWritable

setValue

toStringAST

getChildCount

getChild

getObjectClass

getStartPosition

getEndPosition