private function removeLastNodeFromField($field_name)
{
if (!$this->data_definition->hasIdentifier($field_name)) {
throw new e\NoSuchFieldException(S_SPAN . "The field name {$field_name} does not exist." . E_SPAN);
}
if (!$this->data_definition->isMultiple($field_name)) {
throw new e\NodeException(S_SPAN . "The field {$field_name} is not multiple." . E_SPAN);
}
$first_node = $this->getNode($field_name . a\DataDefinition::DELIMITER . '0');
$par_id = $first_node->getParentId();
if ($par_id == '') {
$last_pos = StructuredDataNode::getPositionOfLastNode($this->children, $field_name);
$first_pos = StructuredDataNode::getPositionOfFirstNode($this->children, $field_name);
$last_id = $this->children[$last_pos]->getIdentifier();
if ($first_pos == $last_pos) {
throw new e\NodeException(S_SPAN . "Cannot remove the only node in the field." . E_SPAN);
}
$child_count = count($this->children);
if ($child_count > $last_pos) {
$before = array_slice($this->children, 0, $last_pos);
$after = array_slice($this->children, $last_pos + 1);
$this->children = array_merge($before, $after);
}
} else {
$this->getNode($par_id)->removeLastChildNode($field_name);
}
if (isset($last_id) && isset($this->node_map[$last_id])) {
unset($this->node_map[$last_id]);
}
$this->identifiers = array_keys($this->node_map);
return $this;
}
