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

    All Methods Instance Methods Concrete Methods
    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, hashCode, setColumnNumber, setLastColumnNumber, setLastLineNumber, setLineNumber, setMetaDataMap, setSourcePosition`

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

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

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

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

- - ### Constructor Detail

    - #### ElvisOperatorExpression

          public ElvisOperatorExpression​(Expression base,
                                         Expression falseExpression)

  - ### Method Detail

    - #### 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`