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