Package groovy.transform

Annotation Type ToString

@Documented
@Retention(RUNTIME)
@Target(TYPE)
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'])
 

Which will have this output:

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

There are numerous options to customize the format of the generated output. E.g. if you change the first annotation to:

 @ToString(includeNames=true)
 

Then the output will be:

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

Or if you change the first annotation to:

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

Then the output will be:

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

If you have this example:

 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)
 

Then the output will be:

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

@ToString can also be used in conjunction with @Canonical and @Immutable.

Since:

1.8.0

Author:

Paul King

See Also:

Immutable, Canonical

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element	Description
java.lang.String	excludes	Comma separated list of field and/or property names to exclude from generated toString.
boolean	includeFields	Include fields as well as properties in generated toString
boolean	includeNames	Whether to include names of properties/fields in generated toString
java.lang.String	includes	Comma separated list of field and/or property names to include within the generated toString.
boolean	includeSuper	Whether to include super in generated toString

Element Detail

excludes

java.lang.String excludes

Comma separated list of field and/or property names to exclude from generated toString. Must not be used if 'includes' is used.

Default:

""

includes

java.lang.String includes

Comma separated list of field and/or property names to include within the generated toString. Must not be used if 'excludes' is used.

Default:

""

includeSuper

boolean includeSuper

Whether to include super in generated toString

Default:

false

includeNames

boolean includeNames

Whether to include names of properties/fields in generated toString

Default:

false

includeFields

boolean includeFields

Include fields as well as properties in generated toString

Default:

false