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Groovy: A powerful, dynamic language for the JVM
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package groovy.transform;
import org.codehaus.groovy.transform.GroovyASTTransformationClass;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
/**
* Class annotation used to assist in the creation of {@code toString()} methods in classes.
* The {@code @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:
*
* {@code @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:
*
* {@code @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:
*
* {@code @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
* {@code @ToString} class NamedThing {
* String name
* }
* {@code @ToString}(includeNames=true,includeSuper=true)
* class AgedThing extends NamedThing {
* int age
* }
* String agedThingAsString = new AgedThing(name:'Lassie', age:5).toString()
* assert agedThingAsString == 'AgedThing(age:5, super:NamedThing(Lassie))'
*
* {@code @ToString} can also be used in conjunction with {@code @Canonical} and {@code @Immutable}.
*
* If you want to omit fields or properties referring to null, you can use the ignoreNulls flag:
*
* import groovy.transform.ToString
* {@code @ToString(ignoreNulls = true)} class NamedThing {
* String name
* }
* assert new NamedThing(name: null).toString() == '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
* {@code @ToString(includePackage = false)} class NamedThing {
* String name
* }
* println new NamedThing(name: "Lassie")
*
* Which results in:
*
* NamedThing(name: Lassie)
*
* If the includePackage flag is {@code true} (the default), then the output will be:
*
* my.company.NamedThing(name: Lassie)
*
* More examples:
*
* //--------------------------------------------------------------------------
* // Most simple implementation of toString.
* import groovy.transform.ToString
*
* {@code @ToString}
* class Person {
* String name
* List likes
* private boolean active = false
* }
*
* def person = new Person(name: 'mrhaki', likes: ['Groovy', 'Java'])
*
* assert person.toString() == 'Person(mrhaki, [Groovy, Java])'
*
*
* //--------------------------------------------------------------------------
* // includeNames to output the names of the properties.
* import groovy.transform.ToString
*
* @ToString(includeNames=true)
* class Person {
* String name
* List likes
* private boolean active = false
* }
*
* def person = new Person(name: 'mrhaki', likes: ['Groovy', 'Java'])
*
* assert person.toString() == 'Person(name:mrhaki, likes:[Groovy, Java])'
*
*
* //--------------------------------------------------------------------------
* // includeFields to not only output properties, but also field values.
* import groovy.transform.ToString
*
* @ToString(includeNames=true, includeFields=true)
* class Person {
* String name
* List likes
* private boolean active = false
* }
*
* def person = new Person(name: 'mrhaki', likes: ['Groovy', 'Java'])
*
* assert person.toString() == 'Person(name:mrhaki, likes:[Groovy, Java], active:false)'
*
*
* //--------------------------------------------------------------------------
* // Use includeSuper to include properties from super class in output.
* import groovy.transform.ToString
*
* @ToString(includeNames=true)
* class Person {
* String name
* List likes
* private boolean active = false
* }
*
* @ToString(includeSuper=true, includeNames=true)
* class Student extends Person {
* List courses
* }
*
* def student = new Student(name: 'mrhaki', likes: ['Groovy', 'Java'], courses: ['IT', 'Business'])
*
* assert student.toString() == 'Student(courses:[IT, Business], super:Person(name:mrhaki, likes:[Groovy, Java]))'
*
*
* //--------------------------------------------------------------------------
* // excludes active field and likes property from output
* import groovy.transform.ToString
*
* @ToString(includeNames=true, includeFields=true, excludes='active,likes')
* class Person {
* String name
* List likes
* private boolean active = false
* }
*
* def person = new Person(name: 'mrhaki', likes: ['Groovy', 'Java'])
*
* assert person.toString() == 'Person(name:mrhaki)'
*
*
* //--------------------------------------------------------------------------
* // Don't include the package name in the output
* package com.mrhaki.blog.groovy
*
* import groovy.transform.*
*
* @ToString(includePackage=false)
* class Course {
* String title
* Integer maxAttendees
* }
*
* final Course course = new Course(title: 'Groovy 101', maxAttendees: 200)
*
* assert course.toString() == 'Course(Groovy 101, 200)'
*
*
* //--------------------------------------------------------------------------
* // Don't use properties with null value.
* package com.mrhaki.blog.groovy
*
* import groovy.transform.*
*
* @ToString(ignoreNulls=true)
* class Course {
* String title
* Integer maxAttendees
* }
*
* final Course course = new Course(title: 'Groovy 101')
*
* assert course.toString() == 'com.mrhaki.blog.groovy.Course(Groovy 101)'
*
*
* //--------------------------------------------------------------------------
* // Cache toString() result.
* package com.mrhaki.blog.groovy
*
* import groovy.transform.*
*
* @ToString(cache=true)
* class Course {
* String title
* Integer maxAttendees
* }
*
* Course course = new Course(title: 'Groovy 101', maxAttendees: 200)
*
* assert course.toString() == 'com.mrhaki.blog.groovy.Course(Groovy 101, 200)'
*
* // Value change will not be reflected in toString().
* course.title = 'Grails with REST'
*
* assert course.toString() == 'com.mrhaki.blog.groovy.Course(Groovy 101, 200)'
* assert course.title == 'Grails with REST'
*
*
* @author Paul King
* @author Andre Steingress
* @see groovy.transform.Immutable
* @see groovy.transform.Canonical
* @since 1.8.0
*/
@java.lang.annotation.Documented
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.TYPE})
@GroovyASTTransformationClass("org.codehaus.groovy.transform.ToStringASTTransformation")
public @interface ToString {
/**
* 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.
*/
String[] excludes() default {};
/**
* 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.
*/
String[] includes() default {};
/**
* Whether to include the toString() of super in the generated toString.
*/
boolean includeSuper() default false;
/**
* Whether to include super properties in the generated toString.
* @since 2.4.0
*/
boolean includeSuperProperties() default false;
/**
* Whether to include names of properties/fields in the generated toString.
*/
boolean includeNames() default false;
/**
* Include fields as well as properties in the generated toString.
*/
boolean includeFields() default false;
/**
* Don't display any fields or properties with value null.
*/
boolean ignoreNulls() default false;
/**
* Whether to include the fully-qualified class name (i.e. including
* the package) or just the simple class name in the generated toString.
* @since 2.0.6
*/
boolean includePackage() default true;
/**
* 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).
* @since 2.1.0
*/
boolean cache() default false;
}