java.lang.Object
org.springframework.expression.spel.ast.SpelNodeImpl
org.springframework.expression.spel.ast.Indexer
All Implemented Interfaces:
Opcodes, SpelNode

public class Indexer extends SpelNodeImpl
An Indexer can index into some proceeding structure to access a particular piece of it. Supported structures are: strings / collections (lists/sets) / arrays.
Since:
3.0
Author:
Andy Clement, Phillip Webb, Stephane Nicoll, Sam Brannen
  • Constructor Details

    • Indexer

      public Indexer(int startPos, int endPos, SpelNodeImpl expr)
  • Method Details

    • getValueInternal

      public TypedValue getValueInternal(ExpressionState state) throws EvaluationException
      Specified by:
      getValueInternal in class SpelNodeImpl
      Throws:
      EvaluationException
    • setValue

      public void setValue(ExpressionState state, @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
      Overrides:
      setValue in class SpelNodeImpl
      Parameters:
      state - 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
    • isWritable

      public boolean isWritable(ExpressionState expressionState) throws SpelEvaluationException
      Description copied from interface: SpelNode
      Determine if this expression node will support a setValue() call.
      Specified by:
      isWritable in interface SpelNode
      Overrides:
      isWritable in class SpelNodeImpl
      Parameters:
      expressionState - the current expression state (includes the context)
      Returns:
      true if the expression node will allow setValue()
      Throws:
      SpelEvaluationException
    • getValueRef

      protected ValueRef getValueRef(ExpressionState state) throws EvaluationException
      Overrides:
      getValueRef in class SpelNodeImpl
      Throws:
      EvaluationException
    • isCompilable

      public boolean isCompilable()
      Description copied from class: SpelNodeImpl
      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.
      Overrides:
      isCompilable in class SpelNodeImpl
      Returns:
      true if this node can be compiled to bytecode
    • generateCode

      public void generateCode(MethodVisitor mv, CodeFlow cf)
      Description copied from class: SpelNodeImpl
      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.
      Overrides:
      generateCode in class SpelNodeImpl
      Parameters:
      mv - the ASM MethodVisitor into which code should be generated
      cf - a context object with info about what is on the stack
    • toStringAST

      public String toStringAST()
      Description copied from interface: SpelNode
      Return the string form the this AST node.
      Returns:
      the string form