我正在设计一个类,它定义了一个非常复杂的对象,其中大多数可选参数为吨(50+),其中许多参数都具有默认值(例如:$type = 'foo'; $width = '300'; $interactive = false;
)。我试图确定设置构造函数和实例/类变量,以最好的方式能够:PHP - 使用大量参数和默认值初始化对象的最佳方法
- 可以很容易地使用类
- 可以很容易地自动文档类(即:使用的phpDocumentor)
- 代码本典雅
在上述的光,我不想是通过构造一吨的参数。我会被传入一个哈希包含初始化值,例如:$foo = new Foo(array('type'=>'bar', 'width'=>300, 'interactive'=>false));
在编码之类的条款,我还是觉得我宁愿......
class Foo {
private $_type = 'default_type';
private $_width = 100;
private $_interactive = true;
...
}
...因为我相信这将有助于文档生成(您可以获得该类的属性列表,让API用户知道他们必须使用哪些“选项”),并且“感觉”是正确的方式。然后你遇到了将构造函数中的传入参数映射到类变量的问题,并且没有利用符号表,你会陷入一种“蛮力”的方式,这对我来说就是击败了目的(虽然我'对其他意见开放)。例如:
function __construct($args){
if(isset($args['type'])) $_type = $args['type']; // yuck!
}
我曾考虑过创建一个本身是关联数组的类变量。初始化这将是非常容易的,然后,例如:
private $_instance_params = array(
'type' => 'default_type',
'width' => 100,
'interactive' => true
);
function __construct($args){
foreach($args as $key=>$value){
$_instance_params[$key] = $value;
}
}
但这好像我没有采取像私有类变量,本地特性优势,而且感觉像文档生成就不会使用这种方法的工作。
感谢您阅读这本书;我可能在这里问了很多,但我是PHP的新手,我真的只是寻找这样做的惯用/优雅的方式。你最好的做法是什么?
附录(关于这个特殊类的细节)
这很可能是这个类是试图做太多,但它是一个古老的Perl库的一个端口,用于创建和处理形式。可能有一种方法可以将配置选项分开以利用继承和多态性,但实际上可能会适得其反。
通过请求,这里是一些参数(Perl代码)的部分列表。你应该看到它们不能很好地映射到子类。
这个类当然有许多这些属性的getter和setter,所以用户可以重载它们;本文的目标(以及原始代码很好地实现的目的)是提供一种紧凑的方式来实例化这些Form对象,并且已经设置了所需的参数。它实际上使非常可读的代码。
# Form Behaviour Parameters
# --------------------------
$self->{id}; # the id and the name of the <form> tag
$self->{name} = "webform"; # legacy - replaced by {id}
$self->{user_id} = $global->{user_id}; # used to make sure that all links have the user id encoded in them. Usually this gets returned as the {'i'} user input parameter
$self->{no_form}; # if set, the <form> tag will be omitted
$self->{readonly}; # if set, the entire form will be read-only
$self->{autosave} = ''; # when set to true, un-focusing a field causes the field data to be saved immediately
$self->{scrubbed}; # if set to "true" or non-null, places a "changed" radio button on far right of row-per-record forms that indicates that a record has been edited. Used to allow users to edit multiple records at the same time and save the results all at once. Very cool.
$self->{add_rowid}; # if set, each row in a form will have a hidden "rowid" input field with the row_id of that record (used primarily for scrubbable records). If the 'scrubbed' parameter is set, this parameter is also automatically set. Note that for this to work, the SELECT statement must pull out a unique row id.
$self->{row_id_prefix} = "row_"; # each row gets a unique id of the form id="row_##" where ## corresponds to the record's rowid. In the case of multiple forms, if we need to identify a specific row, we can change the "row_" prefix to something unique. By default it's "row_"
$self->{validate_form}; # parses user_input and validates required fields and the like on a form
$self->{target}; # adds a target window to the form tag if specified
$self->{focus_on_field}; # if supplied, this will add a <script> tag at the end of the form that will set the focus on the named field once the form loads.
$self->{on_submit}; # adds the onSubmit event handler to the form tag if supplied
$self->{ctrl_s_button_name}; # if supplied with the name of the savebutton, this will add an onKeypress handler to process CTRL-S as a way of saving the form
# Form Paging Parameters
# ----------------------
$self->{max_rows_per_page}; # when displaying a complete form using printForm() method, determines the number of rows shown on screen at a time. If this is blank or undef, then all rows in the query are shown and no header/footer is produced.
$self->{max_pages_in_nav} = 7; # when displaying the navbar above and below list forms, determines how many page links are shown. Should be an odd number
$self->{current_offset}; # the current page that we're displaying
$self->{total_records}; # the number of records returned by the query
$self->{hide_max_rows_selector} = ""; # hide the <select> tag allowing users to choose the max_rows_per_page
$self->{force_selected_row} = ""; # if this is set, calls to showPage() will also clear the rowid hidden field on the form, forcing the first record to be displayed if none were selected
$self->{paging_style} = "normal"; # Options: "compact"
我们当然可以让自己陷入围绕编程风格的更长时间的辩论。但我希望避免它,因为所有参与者的理智!这里(Perl代码,再次)是一个用相当多的一组参数实例化这个对象的例子。
my $form = new Valz::Webform (
id => "dbForm",
form_name => "user_mailbox_recip_list_students",
user_input => \%params,
user_id => $params{i},
no_form => "no_form",
selectable => "checkbox",
selectable_row_prefix => "student",
selected_row => join (",", getRecipientIDsByType('student')),
this_page => $params{c},
paging_style => "compact",
hide_max_rows_selector => 'true',
max_pages_in_nav => 5
);
这听起来像类waaaaaaaaay做很多。你能否详细说明这个班级应该做什么,并且可能列出50个属性中的更多或全部。 – Gordon 2011-05-11 16:14:38
让这些公众成员有什么缺点?您是否需要在施工后对其进行修复,并且不提供任何其他方法来更改这些值? – Mel 2011-05-11 17:00:09
@梅尔 - 除非我有误,否则公开会员并不能改善情况。它只会在前端而不是后端鼓励一些难看的代码。 – 2011-05-11 17:17:05