Newscoop\GimmeBundle\EventListener\Selectable\Doctrine\ORM\Query\SelectWalker::walkSelectStatement PHP Method

    public function walkSelectStatement(SelectStatement $AST)
    {
        $query = $this->_getQuery();
        $fields = $query->getHint('newscoop.api.fields');
        $selectItems = array();
        $parent = null;
        $alias = null;
        foreach ($this->_getQueryComponents() as $dqlAlias => $qComp) {
            if ($qComp['parent'] === null && $qComp['nestingLevel'] == 0) {
                $parent = $qComp;
                $alias = $dqlAlias;
                break;
            }
        }
        $components = $this->_getQueryComponents();
        foreach ($fields as $field) {
            $entityData = $this->findAliasForField($field);
            $orginalField = $field;
            $realField = \Newscoop\Gimme\PropertyMatcher::match($entityData[1], $field);
            if ($field != $realField) {
                $entityData = $this->findAliasForField($realField);
                $field = $realField;
            }
            if ($alias !== false) {
                if (!array_key_exists($alias, $components)) {
                    throw new \UnexpectedValueException("There is no component aliased by [{$alias}] in the given Query");
                }
                $meta = $components[$alias];
                if ($meta['metadata']->hasAssociation($orginalField)) {
                    throw new \UnexpectedValueException("Associations (field {$orginalField}) in partial response are not yet implemented");
                }
                if (!$meta['metadata']->hasField($field)) {
                    throw new \UnexpectedValueException("There is no such field [{$field}] in the given Query component, aliased by [{$alias}]");
                }
            } else {
                if (!array_key_exists($field, $components)) {
                    throw new \UnexpectedValueException("There is no component field [{$field}] in the given Query");
                }
            }
            if ($alias !== false) {
                $pathExpression = new PathExpression(PathExpression::TYPE_STATE_FIELD | PathExpression::TYPE_SINGLE_VALUED_ASSOCIATION, $alias, $field);
                $pathExpression->type = PathExpression::TYPE_STATE_FIELD;
            } else {
                $pathExpression = $field;
            }
            $simpleSelectExpression = new SelectExpression($pathExpression, $orginalField);
            $selectItems[] = $simpleSelectExpression;
        }
        $AST->selectClause->selectExpressions = $selectItems;
    }