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    UnderflowException クラス

    (PHP 5 >= 5.1.0, PHP 7, PHP 8)

    はじめに

    空のコンテナ上で無効な操作 (要素の削除など) を試みたときにスローされる例外です。

    クラス概要

    class UnderflowException extends RuntimeException {
    /* 継承したプロパティ */
    protected string $message = "";
    private string $string = "";
    protected int $code;
    protected string $file = "";
    protected int $line;
    private array $trace = [];
    private ?Throwable $previous = null;
    /* 継承したメソッド */
    public Exception::__construct(string $message = "", int $code = 0, ?Throwable $previous = null)
    final public Exception::getMessage(): string
    final public Exception::getPrevious(): ?Throwable
    final public Exception::getCode(): int
    final public Exception::getFile(): string
    final public Exception::getLine(): int
    final public Exception::getTrace(): array
    final public Exception::getTraceAsString(): string
    public Exception::__toString(): string
    private Exception::__clone(): void
    }

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    User Contributed Notes 1 note

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    0
    Jakub Adamczyk
    2 years ago
    The most typical usage is with stack, queue or collection, for example when you queue tasks, make call stack or manipulate JSON, XML, etc. elements.

    As other exepctions of RuntimeException class, this type of error can't be detected in (for example) your IDE or compiler.

    <?php
    // Functions declared above
    $f1 = function() { setTypeControl('username');};
    $f2 = function() { setTypeControl('userpass');};
    $f3 = function() { setButton('Add');};
    $f4 = function() { setButton('OK');};

    $tasks = new class {
    private     $list;

    // Create internal queue
    public function __construct() {
    $this->list = new SplQueue;
    }

    // Add to queue
    public function add(callable $func) {
    $this->list->enqueue($func);
    }

    // Delete from queue and execute
    public function do() {
    if (    $this->list->isEmpty()) {
    throw new     UnderflowException;
    } else {
    call_user_func($this->list->dequeue());
    }
    }

    };

    $tasks->add($f1);
    $tasks->add($f2);
    $tasks->add($f3);
    $tasks->add($f4);

    $tasks->do(); // Field username is created
    $tasks->do(); // Field userpass is created
    $tasks->do(); // Button Add is created
    $tasks->do(); // Button OK is created
    $tasks->do(); // Fatal error: Uncaught UnderflowException in ...
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