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

public class Elvis extends SpelNodeImpl
Represents the Elvis operator ?:. For an expression a?:b if a is neither null nor an empty String, the value of the expression is a. If a is null or the empty String, then the value of the expression is b.
Since:
3.0
Author:
Andy Clement, Juergen Hoeller, Sam Brannen
  • Constructor Details

    • Elvis

      public Elvis(int startPos, int endPos, SpelNodeImpl... args)
  • Method Details

    • getValueInternal

      public TypedValue getValueInternal(ExpressionState state) throws EvaluationException
      Evaluate the condition and if neither null nor an empty String, return it. If it is null or an empty String, return the other value.
      Specified by:
      getValueInternal in class SpelNodeImpl
      Parameters:
      state - the expression state
      Throws:
      EvaluationException - if the condition does not evaluate correctly to a boolean or there is a problem executing the chosen alternative
    • toStringAST

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