Annotation Type IndexedProperty

@Documented @Retention(SOURCE) @Target(FIELD) public @interface IndexedProperty
Field annotation used with properties to provide an indexed getter and setter for the property. Groovy provides nice GPath syntax support for accessing indexed properties but Java tools or frameworks may expect the JavaBean style getters and setters. Only the getter is produced when an immutable field can be determined.

Example usage: suppose you have a class with the following properties:

 @IndexedProperty FieldType[] someField
 @IndexedProperty List otherField
 @IndexedProperty List furtherField
will add the following methods to the class containing the properties:
 FieldType getSomeField(int index) {
 FieldType getOtherField(int index) {
 Object getFurtherField(int index) {
 void setSomeField(int index, FieldType val) {
     someField[index] = val
 void setOtherField(int index, FieldType val) {
     otherField[index] = val
 void setFurtherField(int index, Object val) {
     furtherField[index] = val
Normal Groovy visibility rules for properties apply (i.e. no public, private or package visibility can be specified) or you will receive a compile-time error message. The normal Groovy property getters and setters will also be created.

More examples:

 import groovy.transform.IndexedProperty

 class Group {
     String name
     List members = []

 class IndexedGroup {
     String name
     @IndexedProperty List members = []

 def group = new Group(name: 'Groovy')
 group.members[0] = 'mrhaki'
 group.members[1] = 'Hubert'
 assert 2 == group.members.size()
 assert ['mrhaki', 'Hubert'] == group.members

 try {
     group.setMembers(0, 'hubert') // Not index property
 } catch (MissingMethodException e) {
     assert e

 def indexedGroup = new IndexedGroup(name: 'Grails')
 indexedGroup.members[0] = 'mrhaki'
 indexedGroup.setMembers 1, 'Hubert'
 assert 2 == indexedGroup.members.size()
 assert 'mrhaki' == indexedGroup.getMembers(0)
 assert 'Hubert' == indexedGroup.members[1]