ABAP Keyword Documentation → ABAP − Reference → Data Interfaces and Communication Interfaces → ABAP and XML → Class Libraries for XML → iXML Library → iXML Library - Access to DOM → iXML Library - DOM Reads
iXML Library - Direct Reads
Direct reads can be used to create references to the node objects in DOM. These references can then be used to access methods and to get the properties of the nodes. Here, any node can be used as the starting point for access to its subnodes.
Other versions:
7.31 | 7.40 | 7.54
Access by Root Element
The root element in DOM, which represents the represented XML data, can be used as the initial node.
The root element of an existing XML document that points to a reference variable document can be accessed as follows:
DATA(element) = document->get_root_element( ).
The static type of the reference variable element is then IF_IXML_ELEMENT
and points to the node object of the root element. The subnodes are now accessed from this node object.
Access to Subnodes
There are two basic methods of accessing subnodes:
Access to adjacent subnodes
The method GET_FIRST_CHILD of the interface IF_IXML_ELEMENT gets the first subnode for an element:
DATA(child) = element->get_first_child( ).
The static type of the reference variable child is then IF_IXML_NODE
and it points to the node object of the first subnode. If there are no subnodes, child is initial.
The method GET_NEXT of the interface IF_IXML_NODE gets the next adjacent node and can be used to get all subnodes in sequence:
DATA(next_child) = child->get_next( ).
The static type of the reference variable next_child is also IF_IXML_NODE. If no adjacent node is found, child_next is initial.
Executable Example
Access using node lists
The method GET_CHILDREN of the interface IF_IXML_ELEMENT gets a list of all subnodes for an element:
DATA(children) = element->get_children( ).
The static type of the reference variable children is then IF_IXML_NODE_LIST
and points to an object containing an indexed list of subnodes. These subnodes can be accessed as follows:
DATA(child) = nodes->get_item( index ).
The static type of the reference variable child is then IF_IXML_NODE
and it points to the subnode specified by the number index (the count begins at zero).
Note
In sequential access to adjacent nodes, access to the node list is also optimized.
Executable Example
Access Using Element Names
If the name is known of an element of an existing XML document pointed to by a reference variable document, the following search for the element is possible:
DATA(element) = document->find_from_name_ns( name = ... ).
The static type of the reference variable element is then IF_IXML_ELEMENT
and it points to the node object that represents the element in question. If the element is not found,
element is initial. The optional parameter DEPTH of the method FIND_FROM_NAME_NS enables the search depth to be restricted.
A further method of the document interface can be used to collect all elements of a name. This method also enables the search depth to be restricted:
DATA(elements) = document->get_elements_by_tag_name_ns( name = ... ).
The static type of the reference variable elements is then IF_IXML_NODE_COLLECTION
and points to an object containing an indexed list of the found elements. These subnodes can be accessed as follows:
DATA(node) = item->get_item( index ).
The static type of the reference variable node is then IF_IXML_NODE
and it points to the node specified by the number index (the count begins at zero).
Executable Example
Access to Attributes
There are various methods for accessing the attributes of elements in DOM.
Attribute access using lists
A reference variable node with the type IF_IXML_NODE, which points to a node object, can be used to create a list of the attributes of the node as follows:
DATA(attributes) = node->get_attributes( ).
The static type of the reference variable attributes is then IF_IXML_NAMED_NODE_MAP
and points to an object containing an indexed list of the attributes. These attributes can be accessed as follows:
DATA(attribute) = attributes->get_item( index ).
The static type of the reference variable attribute is then IF_IXML_ATTRIBUTE
and it points to the object specified by the number index (the count begins at zero).
Instead of the index, the lists of attributes can also be read using the attribute name:
DATA(attribute) = attributes->get_named_item_ns( name = ... ).
attribute then points to the object of attribute specified by the name or is initial.
Short forms for attribute access
Instead of first creating a list of the attributes, they can also be read directly from an element,
using their names. A reference variable element with the type IF_IXML_ELEMENT, which points to an element, can be used to read an attribute as follows:
DATA(attribute) = element->get_attribute_node_ns( name = ... ).
The static type of the reference variable attribute is then IF_IXML_ATTRIBUTE and it points to the object of the attribute specified by the name or is initial.
It is also possible to write only the value of the attribute to a text string directly:
DATA(value) = element->get_attribute_ns( name = ... ).
The type of value is then string and contains the value of the attribute or is initial.
Note
Before the short forms with reference variables with the type IF_IXML_NODE can be executed, a down cast must be performed to the type IF_IXML_ELEMENT, because these methods are only located in this interface.