Package org.codehaus.groovy.ast.expr

# Class ElvisOperatorExpression

java.lang.Object
org.codehaus.groovy.ast.ASTNode
org.codehaus.groovy.ast.AnnotatedNode
org.codehaus.groovy.ast.expr.Expression
org.codehaus.groovy.ast.expr.TernaryExpression
org.codehaus.groovy.ast.expr.ElvisOperatorExpression

All Implemented Interfaces:
  `GroovydocHolder<AnnotatedNode>`, `NodeMetaDataHandler`

    public class ElvisOperatorExpression
    extends TernaryExpression

Represents a short ternary expression x ?: y, which is equal to

     def truePart = x
     def booleanPart = truePart as boolean
     booleanPart? truePart : y

Even if x is no atomic expression, x will be evaluated only once. Example:

     class Foo {
       def index=0
       def getX(){ index++; return index }
     }
     def foo = new Foo()
     def result = foo.x ?: "false case"
     assert foo.index == 1
     assert result == 1

Since:
  1.5

- ## Field Summary

  ### Fields inherited from class org.codehaus.groovy.ast.expr.Expression

  `EMPTY_ARRAY`

  ### Fields inherited from interface groovy.lang.groovydoc.GroovydocHolder

  `DOC_COMMENT`

- ## Constructor Summary

  Constructors
  Constructor | Description
  --- | ---
  `ElvisOperatorExpression​(Expression base, Expression falseExpression)` |

- ## Method Summary

  Modifier and Type | Method | Description
  --- | --- | ---
  `Expression` | `transformExpression​(ExpressionTransformer transformer)` | Return a copy of the expression calling the transformer on any nested expressions
  `void` | `visit​(GroovyCodeVisitor visitor)` |

  ### Methods inherited from class org.codehaus.groovy.ast.expr.TernaryExpression

  `getBooleanExpression, getFalseExpression, getText, getTrueExpression, getType, toString`

  ### Methods inherited from class org.codehaus.groovy.ast.expr.Expression

  `setType, transformExpressions, transformExpressions`

  ### Methods inherited from class org.codehaus.groovy.ast.AnnotatedNode

  `addAnnotation, addAnnotations, getAnnotations, getAnnotations, getDeclaringClass, getGroovydoc, getInstance, hasNoRealSourcePosition, isSynthetic, setDeclaringClass, setHasNoRealSourcePosition, setSynthetic`

  ### Methods inherited from class org.codehaus.groovy.ast.ASTNode

  `copyNodeMetaData, getColumnNumber, getLastColumnNumber, getLastLineNumber, getLineNumber, getMetaDataMap, setColumnNumber, setLastColumnNumber, setLastLineNumber, setLineNumber, setMetaDataMap, setSourcePosition`

  ### Methods inherited from class java.lang.Object

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

  ### Methods inherited from interface org.codehaus.groovy.ast.NodeMetaDataHandler

  `copyNodeMetaData, getNodeMetaData, getNodeMetaData, getNodeMetaData, putNodeMetaData, removeNodeMetaData, setNodeMetaData`

- ## Constructor Details

  - ### ElvisOperatorExpression

    public ElvisOperatorExpression​(Expression base, Expression falseExpression)

- ## Method Details

  - ### visit

    public void visit​(GroovyCodeVisitor visitor)
    Overrides:
      `visit` in class `TernaryExpression`

  - ### transformExpression

    public Expression transformExpression​(ExpressionTransformer transformer)
    Description copied from class: `Expression`
    Return a copy of the expression calling the transformer on any nested expressions
    Overrides:
      `transformExpression` in class `TernaryExpression`