All Known Implementing Classes:
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.
Since:
3.0
Author:
Andy Clement

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`SpelNode`	`getChild(int index)`	Helper method that returns a SpelNode rather than an Antlr Tree node.
`int`	`getChildCount()`	Return the number of children under this node.
`int`	`getEndPosition()`	Return the end position of this AST node in the expression string.
`Class<?>`	`getObjectClass(Object obj)`	Determine the class of the object passed in, unless it is already a class object.
`int`	`getStartPosition()`	Return the start position of this AST node in the expression string.
`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()`	Return the string form the this AST node.

- Method Detail
  - getValue
```
@Nullable
Object getValue(ExpressionState expressionState)
         throws EvaluationException
```
    Evaluate the expression node in the context of the supplied expression state and return the value.
    Parameters:
    expressionState - the current expression state (includes the context)
    Returns:
    the value of this node evaluated against the specified state
    Throws:
    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.
    Parameters:
    expressionState - the current expression state (includes the context)
    Returns:
    the type value of this node evaluated against the specified state
    Throws:
    EvaluationException
  - isWritable
```
boolean isWritable(ExpressionState expressionState)
            throws EvaluationException
```
    Determine if this expression node will support a setValue() call.
    Parameters:
    expressionState - the current expression state (includes the context)
    Returns:
    true if the expression node will allow setValue()
    Throws:
    EvaluationException - if something went wrong trying to determine if the node supports writing
  - setValue
```
void setValue(ExpressionState expressionState,
              @Nullable
              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.
    Parameters:
    expressionState - the current expression state (includes the context)
    newValue - the new value
    Throws:
    EvaluationException - if any problem occurs evaluating the expression or setting the new value
  - toStringAST
```
String toStringAST()
```
    Return the string form the this AST node.
    Returns:
    the string form
  - getChildCount
```
int getChildCount()
```
    Return the number of children under this node.
    Returns:
    the child count
  - getChild
```
SpelNode getChild(int index)
```
    Helper method that returns a SpelNode rather than an Antlr Tree node.
    Returns:
    the child node cast to a SpelNode
  - getObjectClass
```
@Nullable
Class<?> getObjectClass(@Nullable
                        Object obj)
```
    Determine the class of the object passed in, unless it is already a class object.
    Parameters:
    obj - the object that the caller wants the class of
    Returns:
    the class of the object if it is not already a class object, or null if the object is null
  - getStartPosition
```
int getStartPosition()
```
    Return the start position of this AST node in the expression string.
    Returns:
    the start position
  - getEndPosition
```
int getEndPosition()
```
    Return the end position of this AST node in the expression string.
    Returns:
    the end position

Interface SpelNode

Method Summary

Method Detail

getValue

getTypedValue

isWritable

setValue

toStringAST

getChildCount

getChild

getObjectClass

getStartPosition

getEndPosition