PHP 编程的 5个良好习惯(5)

<?php
/**
* Counts the number of messages found in the array of
* ResultMessage with the getSeverity() value of "Error"
*
* @param $messages An array of ResultMessage
* @return unknown_type
*/
function countErrors($messages)
{
$matchingCount = 0;
foreach($messages as $m) {
if ($m->getSeverity() == "Error") {
$matchingCount++;
}
}
return $matchingCount;
}

/**
* Counts the number of messages found in the array of
* ResultMessage with the getSeverity() value of "Warning"
*
* @param $messages An array of ResultMessage
* @return unknown_type
*/
function countWarnings($messages)
{
$matchingCount = 0;
foreach($messages as $m) {
if ($m->getSeverity() == "Warning") {
$matchingCount++;
}
}
return $matchingCount;
}

/**
* Counts the number of messages found in the array of
* ResultMessage with the getSeverity() value of "Information"
*
* @param $messages An array of ResultMessage
* @return unknown_type
*/
function countInformation($messages)
{
$matchingCount = 0;
foreach($messages as $m) {
if ($m->getSeverity() == "Information") {
$matchingCount++;
}
}
return $matchingCount;
}

$messages = array(new ResultMessage("Error", "This is an error!"),
new ResultMessage("Warning", "This is a warning!"),
new ResultMessage("Error", "This is another error!"));

$errs = countErrors($messages);

echo("There are " . $errs . " errors in the result.\n");
?>
 

良好习惯：带参数的可重用函数

清单 10 展示了修改后的代码，它将复制的代码放到一个方法中。另一个方法也进行了更改，它现在将任务委托给新的方法。构建通用的方法需要花时间设计，并且这样做使您能停下来思考，而不是本能地使用复制粘贴。但有必要进行更改时，对通用的方法投入的时间将得到回报。

清单 10. 良好习惯：带参数的可重用函数

<?php
/*
* Counts the messages with the given severity in the array
* of messages.
*
* @param $messages An array of ResultMessage
* @return int Count of messages matching $withSeverity
*/
function countMessages($messages, $withSeverity)
{
$matchingCount = 0;
foreach($messages as $m) {
if ($m->getSeverity() == $withSeverity) {
$matchingCount++;
}
}
return $matchingCount;
}

/**
* Counts the number of messages found in the array of
* ResultMessage with the getSeverity() value of "Error"
*
* @param $messages An array of ResultMessage
* @return unknown_type
*/
function countErrors($messages)
{
return countMessages($messages, "Errors");
}

/**
* Counts the number of messages found in the array of
* ResultMessage with the getSeverity() value of "Warning"
*
* @param $messages An array of ResultMessage
* @return unknown_type
*/
function countWarnings($messages)
{
return countMessages($messages, "Warning");
}

/**
* Counts the number of messages found in the array of
* ResultMessage with the getSeverity() value of "Warning"
*
* @param $messages An array of ResultMessage
* @return unknown_type
*/
function countInformation($messages)
{
return countMessages($messages, "Information");
}

$messages = array(new ResultMessage("Error", "This is an error!"),
new ResultMessage("Warning", "This is a warning!"),
new ResultMessage("Error", "This is another error!"));

$errs = countErrors($messages);

echo("There are " . $errs . " errors in the result.\n");

?>
 

结束语

如果您在编写 PHP 代码的过程中养成本文讨论的良好习惯，您将能够构建易读、易理解、易维护的代码。使用这种方式构建的易维护代码将降低调试、修复和扩展代码所面临的风险。

使用良好的名称和更短的方法能够提高代码的可读性。注释代码的目的有利于代码理解和扩展。适当地处理错误会使代码更加健壮。最后，停止使用复制粘贴，保持代码干净，提高可重用性。

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