The FilterIterator class

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

    Introduction

    This abstract iterator filters out unwanted values. This class should be extended to implement custom iterator filters. The FilterIterator::accept() must be implemented in the subclass.

    Class synopsis

    abstract class FilterIterator extends IteratorIterator {
    /* Methods */
    public __construct(Iterator $iterator)
    public accept(): bool
    public current(): mixed
    public key(): mixed
    public next(): void
    public rewind(): void
    public valid(): bool
    /* Inherited methods */
    public IteratorIterator::current(): mixed
    public IteratorIterator::getInnerIterator(): ?Iterator
    public IteratorIterator::key(): mixed
    public IteratorIterator::next(): void
    public IteratorIterator::rewind(): void
    public IteratorIterator::valid(): bool
    }

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    User Contributed Notes 3 notes

    up
    24
    Venelin Vulkov
    16 years ago
    The code below is a simple example of usage . Note that the method which does the actual job is accept.

    <?php
    class UserFilter extends FilterIterator
    {
    private     $userFilter;

    public function     __construct(Iterator $iterator , $filter )
    {
    parent::__construct($iterator);
    $this->userFilter = $filter;
    }

    public function     accept()
    {
    $user = $this->getInnerIterator()->current();
    if(     strcasecmp($user['name'],$this->userFilter) == 0) {
    return     false;
    }
    return     true;
    }
    }

    $array = array(
    array(    'name' => 'Jonathan','id' => '5'),
    array(    'name' => 'Abdul' ,'id' => '22')
    );

    $object = new ArrayObject($array);

    // Note it is case insensitive check in our example due the usage of strcasecmp function
    $iterator = new UserFilter($object->getIterator(),'abdul');

    foreach (    $iterator as $result) {
    echo     $result['name'];
    }

    /* Outputs Jonathan */

    ?>
    Regards.
    up
    6
    Anonymous
    11 years ago
    A little test about the function call order:

    <?php

    class TestIterator extends IteratorIterator
    {
    public function     key()
    {
    echo     __FUNCTION__, PHP_EOL;
    return     parent::key();
    }

    public function     next()
    {
    echo     __FUNCTION__, PHP_EOL;
    return     parent::next();
    }

    public function     rewind()
    {
    echo     __FUNCTION__, PHP_EOL;
    return     parent::rewind();
    }

    public function     valid()
    {
    echo     __FUNCTION__, PHP_EOL;
    return     parent::valid();
    }
    }

    class     TestFilterIterator extends FilterIterator
    {
    public function     accept()
    {
    echo     __FUNCTION__, PHP_EOL;
    return     true;
    }
    }

    $iterator = new ArrayIterator(array('a', 'b', 'c'));

    foreach (new     TestFilterIterator(new TestIterator($iterator)) as $k => $v) {
    echo     PHP_EOL;
    }

    ?>

    This will output the following:

    rewind
    valid
    key
    accept

    next
    valid
    key
    accept

    next
    valid
    key
    accept

    next
    valid
    up
    -1
    Anonymous
    3 years ago
    Filter object collection by method:
    <?php
    /**
    * @method object current()
    */
    class CollectionFilterIterator extends FilterIterator
    {
    private     $methodName;
    private     $methodArguments;

    public function function     __construct(Iterator $collection, string $methodName, array $methodArguments = [])
    {
    parent::__construct($collection);
    $this->methodName = $methodName;
    $this->methodArguments = array_values($methodArguments);
    }

    public function     accept(): bool
    {
    return (bool)     $this->current()->{$this->methodName}(...$this->methodArguments);
    // or call_user_func_array([$this->current(), $this->methodName], $this->methodArguments);
    }
    }
    ?>
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