org.springframework.expression.spel.ast
Class FunctionReference

java.lang.Object
  org.springframework.expression.spel.ast.SpelNodeImpl
      org.springframework.expression.spel.ast.FunctionReference

All Implemented Interfaces:

SpelNode

public class FunctionReference
extends SpelNodeImpl

A function reference is of the form "#someFunction(a,b,c)". Functions may be defined in the context prior to the expression being evaluated or within the expression itself using a lambda function definition. For example: Lambda function definition in an expression: "(#max = {|x,y|$x>$y?$x:$y};max(2,3))" Calling context defined function: "#isEven(37)". Functions may also be static java methods, registered in the context prior to invocation of the expression.

Functions are very simplistic, the arguments are not part of the definition (right now), so the names must be unique.

Since:

3.0

Author:

Andy Clement

Field Summary

private java.lang.String

name

Fields inherited from class org.springframework.expression.spel.ast.SpelNodeImpl

children, pos

Constructor Summary

FunctionReference(java.lang.String functionName, int pos, SpelNodeImpl... arguments)

Method Summary

private TypedValue	executeFunctionJLRMethod(ExpressionState state, java.lang.reflect.Method method) Execute a function represented as a java.lang.reflect.Method.
private java.lang.Object[]	getArguments(ExpressionState state) Compute the arguments to the function, they are the children of this expression node.
TypedValue	getValueInternal(ExpressionState state)
java.lang.String	toStringAST()

Methods inherited from class org.springframework.expression.spel.ast.SpelNodeImpl

getChild, getChildCount, getEndPosition, getObjectClass, getPreviousChild, getStartPosition, getTypedValue, getValue, getValue, isWritable, nextChildIs, setValue

Methods inherited from class java.lang.Object

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

Field Detail

name

private final java.lang.String name

Constructor Detail

FunctionReference

public FunctionReference(java.lang.String functionName,
                         int pos,
                         SpelNodeImpl... arguments)

Method Detail

getValueInternal

public TypedValue getValueInternal(ExpressionState state)
                            throws EvaluationException

Specified by:

getValueInternal in class SpelNodeImpl

Throws:

EvaluationException

executeFunctionJLRMethod

private TypedValue executeFunctionJLRMethod(ExpressionState state,
                                            java.lang.reflect.Method method)
                                     throws EvaluationException

Execute a function represented as a java.lang.reflect.Method.

Parameters:

state - the expression evaluation state

the - java method to invoke

Returns:

the return value of the invoked Java method

Throws:

EvaluationException - if there is any problem invoking the method

toStringAST

public java.lang.String toStringAST()

Specified by:

toStringAST in interface SpelNode

Specified by:

toStringAST in class SpelNodeImpl

Returns:

the string form of this AST node

getArguments

private java.lang.Object[] getArguments(ExpressionState state)
                                 throws EvaluationException

Compute the arguments to the function, they are the children of this expression node.

Returns:

an array of argument values for the function call

Throws:

EvaluationException