Package org.springframework.expression.spel.ast

Class SpelNodeImpl

    • Field Detail

      • exitTypeDescriptor

        @Nullable
protected volatile String exitTypeDescriptor
        Indicates the type descriptor for the result of this expression node. This is set as soon as it is known. For a literal node it is known immediately. For a property access or method invocation it is known after one evaluation of that node.

        The descriptor is like the bytecode form but is slightly easier to work with. It does not include the trailing semicolon (for non array reference types). Some examples: Ljava/lang/String, I, [I

    • Method Detail

      • nextChildIs

        protected boolean nextChildIs​(Class<?>... classes)
        Return true if the next child is one of the specified classes.

      • isWritable

        public boolean isWritable​(ExpressionState expressionState)
                   throws EvaluationException
        Description copied from interface: SpelNode
        Determine if this expression node will support a setValue() call.
        Specified by:
        isWritable in interface SpelNode
        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

        public void setValue​(ExpressionState expressionState,
                     @Nullable
                     Object newValue)
              throws EvaluationException
        Description copied from interface: SpelNode
        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.
        Specified by:
        setValue in interface SpelNode
        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

      • getChild

        public SpelNode getChild​(int index)
        Description copied from interface: SpelNode
        Helper method that returns a SpelNode rather than an Antlr Tree node.
        Specified by:
        getChild in interface SpelNode
        Returns:
        the child node cast to a SpelNode

      • getObjectClass

        @Nullable
public Class<?> getObjectClass​(@Nullable
                               Object obj)
        Description copied from interface: SpelNode
        Determine the class of the object passed in, unless it is already a class object.
        Specified by:
        getObjectClass in interface SpelNode
        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

      • getEndPosition

        public int getEndPosition()
        Description copied from interface: SpelNode
        Return the end position of this AST node in the expression string.
        Specified by:
        getEndPosition in interface SpelNode
        Returns:
        the end position

      • isCompilable

        public boolean isCompilable()
        Check whether a node can be compiled to bytecode. The reasoning in each node may be different but will typically involve checking whether the exit type descriptor of the node is known and any relevant child nodes are compilable.
        Returns:
        true if this node can be compiled to bytecode

      • generateCode

        public void generateCode​(MethodVisitor mv,
                         CodeFlow cf)
        Generate the bytecode for this node into the supplied visitor. Context info about the current expression being compiled is available in the codeflow object, e.g. including information about the type of the object currently on the stack.
        Parameters:
        mv - the ASM MethodVisitor into which code should be generated
        cf - a context object with info about what is on the stack

      • generateCodeForArguments

        protected static void generateCodeForArguments​(MethodVisitor mv,
                                               CodeFlow cf,
                                               Member member,
                                               SpelNodeImpl[] arguments)
        Generate code that handles building the argument values for the specified method. This method will take account of whether the invoked method is a varargs method and if it is then the argument values will be appropriately packaged into an array.
        Parameters:
        mv - the method visitor where code should be generated
        cf - the current codeflow
        member - the method or constructor for which arguments are being setup
        arguments - the expression nodes for the expression supplied argument values