framework/data/Pagination.php
public function setPage($value, $validatePage = false)
    {
        if ($value === null) {
            $this->_page = null;
        } else {
            $value = (int) $value;
            if ($validatePage && $this->validatePage) {
                $pageCount = $this->getPageCount();
                if ($value >= $pageCount) {
                    $value = $pageCount - 1;
                }
            }
            if ($value < 0) {
                $value = 0;
            }
            $this->_page = $value;
        }
    }
public function setPage($value, $validatePage = false)
    {
        if ($value === null) {
            $this->_page = null;
        } else {
            $value = (int) $value;
            if ($validatePage && $this->validatePage) {
                $pageCount = $this->getPageCount();
                if ($value >= $pageCount) {
                    $value = $pageCount - 1;
                }
            }
            if ($value < 0) {
                $value = 0;
            }
            $this->_page = $value;
        }
    }
Sets the current page number.
@param int $value the zero-based index of the current page.
@param bool $validatePage whether to validate the page number. Note that in order
to validate the page number, both [[validatePage]] and this parameter must be true.