PHP：致命错误：调用非对象上的成员函数Call to a member function on a non-object

PHP: Fatal error: Call to a member function on a non-object

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这里出现了一个非常奇怪的错误，我正在编写一个平面文件数据库类，在刷新之前，这一切都正常工作，现在我不断收到以下消息：

Fatal error: Call to a member function name() on a non-object in
/home/reithg/public_html/test/engine/class.database.php on line 50

我给班级打电话如下：

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<?php
ini_set('display_errors', '1');

require('engine/class.database.php');

$config = new Config("lessons", array('first', 'second', 'third', 'fourth'),"data/");
$db = new Database($config, true);

print("Querying DB for 'theta' no exclusions: ");
print_r($db->query('theta', NULL, NULL));

print(" Querying DB for 'theta' in column 'second': ");
print_r($db->query('theta', 'second', NULL));

print(" Querying DB for first two rows: ");
print_r($db->getRows(2));

print(" Querying DB for last three rows: ");
print_r($db->getRows(3, true));

print(" Cleaning data for safe DB input: ");
$testInput = array('escape|these||delimiters','and\these\\slashes','and\0these\0nulls',"don't, forget quotes");
print("input:");
print_r($testInput);
echo(" output:");
print($db->addRow($testInput));
?>

这是我的class.database.php

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<?php
require('class.config.php');
require('class.column.php');

class Database {
private
$_config,
$_pointer;

public function __construct(Config $config) {
$this->_config = $config;
return true;
}

private function connect($method) {
if (!($this->_pointer = @fopen($this->_config->db(), $method)))
echo("Unable to connect to database");
}

private function disconnect() {
fclose($this->_pointer);
}

private function lock($method) {
if(flock($this->_pointer, $method))
return true;
return false;
}

private function unlock() {
flock($this->_pointer, LOCK_UN);
}

private function cleanInput($input) {
$data = array_map(array($this, 'escapeData'), $input);
$output = implode($this->_config->delimiter(), $data)."

";
return $output;
}

private function escapeData($data)
{
$search = array('\', '"',"'", '\\0', '
', $this->_config->delimiter());
$replace = array('\\\', '"',"\'", '\\0', '\
', '\'.$this->_config->delimiter());
$output = str_replace(array_unique($search), array_unique($replace), $data);
return $output;
}

private function formatRow($data) {
foreach($data as $key => $value) {
$row[$this->_config->columns($key,"position")->name()] = $value;
}
return $row;
}

public function dumpToArray() {
$arrayDump;
foreach(file($this->_config->db(), FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES) as $row => $content)
$arrayDump[$row] = formatRow(explode($this->_config->delimiter(),$content));
return $arrayDump;
}

public function addRow(array $data) {
$this->connect('ab');
if($this->lock(LOCK_EX)) {
// fwrite($this->_pointer, $this->cleanInput($data));
echo($this->cleanInput($data));
$this->unlock();
$this->disconnect();
return true;
} else {
$this->disconnect();
return false;
}
}

public function query($value, $column = NULL, $limit = NULL) {
$this->connect('rb');
$results = array();
while ((is_null($limit) || (count($results) < $limit)) && !feof($this->_pointer)) {
$data = explode($this->_config->delimiter(), fgets($this->_pointer, 1024));
if(!is_null($column)) {
if ($data[$this->_config->columns($column,"string")->index()] == $value)
array_push($results, $this->formatRow($data));
} else {
if (in_array($value, $data))
array_push($results, $this->formatRow($data));
}
}
$this->disconnect();
switch (count($results)) {
case 0;
return false;
case 1;
return $results[0];
default;
return $results;
}
}

public function getRows($limit = 1, $reverse = false) {
$this->connect('rb');
$offset = 0;
$results = array();
if ($reverse) {
while(count($results) < $limit && fseek($this->_pointer, $offset, SEEK_END) >= 0) {
$char = fgetc($this->_pointer);
if($char =="
" || $char =="
"){
$offset --;
$data = explode($this->_config->delimiter(), fgets($this->_pointer, 1024));
array_push($results, $this->formatRow($data));
}
$offset--;
}
$results = array_reverse($results);
} else {
while ((($limit === NULL) || (count($results) < $limit)) && !feof($this->_pointer)) {
$data = explode($this->_config->delimiter(), fgets($this->_pointer, 1024));
array_push($results, $this->formatRow($data));
}
}
$this->disconnect();
return $results;
}
}
?>

class.config.php类

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<?php
class Config {
private
$_db,
$_file,
$_columns = array(),
$_directory,
$_delimiter;

public function __construct($file, array $columns, $directory = NULL, $delimiter ="|") {
$this->_db = $directory.$file.".db";
$this->defineColumns($columns);
$this->_directory = $directory;
$this->_delimiter = $delimiter;
}

public function db() {
return $this->_db;
}

public function delimiter() {
return $this->_delimiter;
}

private function defineColumns($constants) {
for ($i=0;$i<count($constants);$i++) {
if(in_array($constants[$i], $this->_columns))
die("Column names must be unique");
$column = new Column($constants[$i], $i);
$this->_columns[$column->name()] = $column;
}
}

public function columns($index, $search ="string") {
switch ($search) {
case"string";
return $this->_columns[$index];
break;
case"position";
$keys = array_keys($this->_columns);
return $this->_columns[$keys[$index]];
break;
default;
return false;
}
}
}
?>

class.column.php类

<?php
class Column {
const
ALL ="0",
STRING ="1",
NUMBER ="2",
INT ="3",
AUTO_INCREMENT ="4",
CURRENT_TIME ="5";

private
$_type = ALL,
$_name,
$_index,
$_maxChars ="256";

public function __construct($name, $index, $type = NULL, $maxChars = NULL) {
$this->_name = $name;
$this->_index = $index;
if(!is_null($type))
setDataType($type);
if(!is_null($maxChars))
setMaxChars($maxChars);
return $this;
}

public function setDataType($type) {
switch ($type) {
case ALL;
case STRING;
case NUMBER;
case INT;
case AUTO_INCREMENT;
case CURRENT_TIME;
$this->_type = $type;
break;
default;
return false;
}
}

public function auditData($data) {
switch ($this->_type) {
case ALL;
$output = $data;
break;
case STRING;
$output = (string) $data;
break;
case NUMBER;
$output = (float) $data;
break;
case INT;
$output = (int) $data;
break;
case AUTO_INCREMENT;
$output = (int) $data;
break;
case CURRENT_TIME;
$output = time();
break;
default;
return false;
}
return $output;
}

public function setMaxChars($maxChars) {
if(is_int($maxChars)) {
$this->_maxChars = $maxChars;
}
}

public function name() {
return $this->_name;
}

public function index() {
return $this->_index;
}
}
?>

我知道这是很多代码，但我不明白为什么这会突然发生，实际上是一次刷新而没有对代码进行任何更改。即使我回溯到以前的版本，也会发生这种情况。

当我试图这样做时：

1	print($this->_config->columns($key,"position"));

它返回：

Catchable fatal error: Object of class Column could not be converted
to string in /home/reithg/public_html/test/engine/class.database.php
*on line 50*

这表明我正在类列的一个成员上执行name()，该成员具有一个名为name()的公共方法。

当我这样做的时候：

1	print($this->_config->columns($key,"position")->name());

它返回(一次返回一个单词，就像在foreach循环中一样)；

first second third fourth first second third fourth

所以很明显，它在它前面有一条线在工作。