BNodeLabeler.php
No OneTemporary
Actions

Size

1 KB

Referenced Files

None

Subscribers

None

BNodeLabeler.php
View Options

	<?php

	namespace Wikimedia\Purtle;

	use InvalidArgumentException;

	/**
	* Helper class for generating labels for blank nodes.
	*
	* This serves as a holder for the bnode counter that can be shared between multiple RdfWriter
	* instances, to avoid conflicting ids.
	*
	* @license GPL-2.0-or-later
	* @author Daniel Kinzler
	*/
	class BNodeLabeler {

	/**
	* @var string
	*/
	private $prefix;

	/**
	* @var int
	*/
	private $counter;

	/**
	* @param string $prefix
	* @param int $start
	*
	* @throws InvalidArgumentException
	*/
	public function __construct( $prefix = 'genid', $start = 1 ) {
	if ( !is_string( $prefix ) ) {
	throw new InvalidArgumentException( '$prefix must be a string' );
	}

	if ( !is_int( $start ) \|\| $start < 1 ) {
	throw new InvalidArgumentException( '$start must be an int >= 1' );
	}

	$this->prefix = $prefix;
	$this->counter = $start;
	}

	/**
	* @param string\|null $label node label; will be generated if not given.
	*
	* @return string
	*/
	public function getLabel( $label = null ) {
	if ( $label === null ) {
	$label = $this->prefix . $this->counter;
	$this->counter++;
	}

	return $label;
	}

	}