groovy.transform
[Java] Annotation Type ToString

java.lang.Object
  groovy.transform.ToString

@java.lang.annotation.Retention(RetentionPolicy.RUNTIME)
@java.lang.annotation.Target({ElementType.TYPE})
@GroovyASTTransformationClass("org.codehaus.groovy.transform.ToStringASTTransformation")
public @interface ToString

Class annotation used to assist in the creation of toString() methods in classes. The @ToString annotation instructs the compiler to execute an AST transformation which adds the necessary toString() method.

It allows you to write classes in this shortened form:

 @ToString
 class Customer {
     String first, last
     int age
     Date since = new Date()
     Collection favItems
     private answer = 42
 }
 println new Customer(first:'Tom', last:'Jones', age:21, favItems:['Books', 'Games'])
 

 Customer(Tom, Jones, 21, Wed Jul 14 23:57:14 EST 2010, [Books, Games])
 

 @ToString(includeNames=true)
 

 Customer(first:Tom, last:Jones, age:21, since:Wed Jul 14 23:57:50 EST 2010, favItems:[Books, Games])
 

 @ToString(includeNames=true,includeFields=true,excludes="since,favItems")
 

 Customer(first:Tom, last:Jones, age:21, answer:42)
 

 import groovy.transform.ToString
 @ToString class NamedThing {
     String name
 }
 @ToString(includeNames=true,includeSuper=true)
 class AgedThing extends NamedThing {
     int age
 }
 println new AgedThing(name:'Lassie', age:5)
 

 AgedThing(age:5, super:NamedThing(Lassie))
 

If you want to omit fields or properties referring to null, you can use the ignoreNulls flag:

 import groovy.transform.ToString
 @ToString(ignoreNulls = true) class NamedThing {
     String name
 }
 println new NamedThing(name: null)
 

 NamedThing()
 

By default the fully-qualified class name is used as part of the generated toString. If you want to exclude the package, you can set the includePackage flag to false, e.g.:

 package my.company
 import groovy.transform.ToString
 @ToString(includePackage = false) class NamedThing {
     String name
 }
 println new NamedThing(name: "Lassie")
 

 NamedThing(name: Lassie)
 

 my.company.NamedThing(name: Lassie)
 

Authors:

Paul King

Andre Steingress

See Also:

Immutable

Canonical

Since:

1.8.0

cache

public boolean cache

Whether to cache toString() calculations. You should only set this to true if you know the object is immutable (or technically mutable but never changed). @default false

Since:

2.1.0

excludes

public java.lang.String[] excludes

List of field and/or property names to exclude from generated toString. Must not be used if 'includes' is used. For convenience, a String with comma separated names can be used in addition to an array (using Groovy's literal list notation) of String values. @default {}

ignoreNulls

public boolean ignoreNulls

Don't display any fields or properties with value null. @default false

includeFields

public boolean includeFields

Include fields as well as properties in generated toString. @default false

includeNames

public boolean includeNames

Whether to include names of properties/fields in generated toString. @default false

includePackage

public boolean includePackage

Whether to include the fully-qualified class name (i.e. including the package) or just the simple class name in the generated toString. @default true

Since:

2.0.6

includeSuper

public boolean includeSuper

Whether to include super in generated toString. @default false

includes

public java.lang.String[] includes

List of field and/or property names to include within the generated toString. Must not be used if 'excludes' is used. For convenience, a String with comma separated names can be used in addition to an array (using Groovy's literal list notation) of String values. @default {}

Groovy Documentation