Indexer

<?php
namespace FooBar\BarFoo\Solr\IndexQueue;

use ApacheSolrForTypo3\Solr\IndexQueue\InvalidFieldNameException;

/**
 * Class Indexer
 *
 * @package FooBar\BarFoo\Solr\IndexQueue
 */
class Indexer extends \ApacheSolrForTypo3\Solr\IndexQueue\Indexer
{
    /**
     * Holds field names that are denied to overwrite in thy indexing configuration.
     *
     * @var array
     */
    protected static $unAllowedOverrideFields = [];

    /**
     * @param string $solrFieldName
     * @return bool
     */
    public static function isAllowedToOverrideField($solrFieldName)
    {
        return !in_array($solrFieldName, static::$unAllowedOverrideFields);
    }

    /**
     * Adds fields to the document as defined in $indexingConfiguration
     *
     * @param \Apache_Solr_Document $document base document to add fields to
     * @param array $indexingConfiguration Indexing configuration / mapping
     * @param array $data Record data
     *
     * @return \Apache_Solr_Document Modified document with added fields
     * @throws \ApacheSolrForTypo3\Solr\IndexQueue\InvalidFieldNameException
     */
    protected function addDocumentFieldsFromTyposcript(
        \Apache_Solr_Document $document,
        array $indexingConfiguration,
        array $data
    ) {

        // mapping of record fields => solr document fields, resolving cObj
        foreach ($indexingConfiguration as $solrFieldName => $recordFieldName) {
            if (is_array($recordFieldName)) {
                // configuration for a content object, skipping
                continue;
            }

            if (!static::isAllowedToOverrideField($solrFieldName)) {
                throw new InvalidFieldNameException(
                    'Must not overwrite field .' . $solrFieldName,
                    1435441863
                );
            }

            $fieldValue = $this->resolveFieldValue($indexingConfiguration,
                $solrFieldName, $data);

            if (is_array($fieldValue)) {
                // multi value
                foreach ($fieldValue as $multiValue) {
                    $document->addField($solrFieldName, $multiValue);
                }
            } else {
                if ($fieldValue !== '' && $fieldValue !== null) {
                    $document->setField($solrFieldName, $fieldValue);
                }
            }
        }

        return $document;
    }
}