REPORT zdp_iterator.

CLASS lcl_item DEFINITION.

PUBLIC SECTION.

METHODS: constructor IMPORTING iv_name TYPE string.

DATA: v_name TYPE string READ-ONLY.

ENDCLASS.

CLASS lcl_item IMPLEMENTATION.

METHOD constructor.

v_name = iv_name.

ENDMETHOD.

ENDCLASS.

INTERFACE if_collection DEFERRED.

INTERFACE if_iterator.

METHODS: get_index RETURNING VALUE(index) TYPE i,

has_next RETURNING VALUE(has_next) TYPE flag,

get_next RETURNING VALUE(object) TYPE REF TO object,

first RETURNING VALUE(object) TYPE REF TO object,

set_step IMPORTING VALUE(iv_step) TYPE i.

DATA: v_step TYPE i.

DATA: v_current TYPE i.

DATA: o_collection TYPE REF TO if_collection.

ENDINTERFACE.

INTERFACE if_collection.

METHODS: get_iterator RETURNING VALUE(iterator) TYPE REF TO if_iterator.

METHODS: add IMPORTING element TYPE REF TO object,

remove IMPORTING element TYPE REF TO object,

clear,

size RETURNING VALUE(size) TYPE i,

is_empty RETURNING VALUE(empty) TYPE flag,

get IMPORTING index TYPE i

RETURNING VALUE(object) TYPE REF TO object.

ENDINTERFACE.

CLASS lcl_iterator DEFINITION.

PUBLIC SECTION.

INTERFACES: if_iterator.

METHODS: constructor IMPORTING io_collection TYPE REF TO if_collection.

ALIASES: get_index FOR if_iterator~get_index,

has_next FOR if_iterator~has_next,

get_next FOR if_iterator~get_next,

first FOR if_iterator~first,

set_step FOR if_iterator~set_step.

PRIVATE SECTION.

ALIASES: v_step FOR if_iterator~v_step,

v_current FOR if_iterator~v_current,

o_collection FOR if_iterator~o_collection.

ENDCLASS.

CLASS lcl_collection DEFINITION.

PUBLIC SECTION.

INTERFACES: if_collection.

DATA: i_items TYPE STANDARD TABLE OF REF TO object.

ALIASES: get_iterator FOR if_collection~get_iterator,

add FOR if_collection~add,

remove FOR if_collection~clear,

clear FOR if_collection~size,

size FOR if_collection~is_empty,

get FOR if_collection~get.

ENDCLASS.

CLASS lcl_collection IMPLEMENTATION.

METHOD if_collection~get_iterator.

CREATE OBJECT iterator

TYPE lcl_iterator

EXPORTING

io_collection = me.

ENDMETHOD.

METHOD if_collection~add.

APPEND element TO i_items.

ENDMETHOD.

METHOD if_collection~remove.

DELETE i_items WHERE table_line EQ element.

ENDMETHOD.

METHOD if_collection~clear.

CLEAR: i_items.

ENDMETHOD.

METHOD if_collection~size.

size = lines( i_items ).

ENDMETHOD.

METHOD if_collection~is_empty.

IF me->size( ) IS INITIAL.

empty = 'X'.

ENDIF.

ENDMETHOD.

METHOD if_collection~get.

READ TABLE i_items INTO object INDEX index.

ENDMETHOD.

ENDCLASS.

CLASS lcl_iterator IMPLEMENTATION.

METHOD constructor.

o_collection = io_collection.

v_step = 1.

ENDMETHOD.

METHOD if_iterator~first.

v_current = 1.

object = o_collection->get( v_current ).

ENDMETHOD.

METHOD if_iterator~get_next.

v_current = v_current + v_step.

object = o_collection->get( v_current ).

ENDMETHOD.

METHOD if_iterator~has_next.

DATA obj TYPE REF TO object.

DATA idx TYPE i.

idx = v_current + v_step.

obj = o_collection->get( idx ).

IF obj IS BOUND.

has_next = 'X'.

ENDIF.

ENDMETHOD.

METHOD if_iterator~set_step.

me->v_step = iv_step.

ENDMETHOD.

METHOD if_iterator~get_index.

index = index.

ENDMETHOD.

ENDCLASS.

CLASS lcl_main DEFINITION.

PUBLIC SECTION.

CLASS-METHODS:run.

ENDCLASS.

CLASS lcl_main IMPLEMENTATION.

METHOD run.

DATA: o_collection TYPE REF TO if_collection.

DATA: o_iterator TYPE REF TO if_iterator.

DATA: lo_item TYPE REF TO lcl_item.

CREATE OBJECT o_collection TYPE lcl_collection.

o_iterator = o_collection->get_iterator( ).

CREATE OBJECT lo_item

EXPORTING

iv_name = 'Item1'.

o_collection->add( lo_item ).

CREATE OBJECT lo_item

EXPORTING

iv_name = 'Item2'.

o_collection->add( lo_item ).

CREATE OBJECT lo_item

EXPORTING

iv_name = 'Item3'.

o_collection->add( lo_item ).

CREATE OBJECT lo_item

EXPORTING

iv_name = 'Item4'.

o_collection->add( lo_item ).

CREATE OBJECT lo_item

EXPORTING

iv_name = 'Item5'.

o_collection->add( lo_item ).

WHILE o_iterator->has_next( ) IS NOT INITIAL.

lo_item ?= o_iterator->get_next( ).

WRITE: / lo_item->v_name.

ENDWHILE.

ENDMETHOD.

ENDCLASS.

START-OF-SELECTION.

lcl_main=>run( ).