my changes

app/Library/Search/Navigation.php

@@ -0,0 +1,68 @@
+<?php
+namespace App\Library\Search;
+
+use App\Library\Util\QueryBuilder;
+use App\Library\Util\Searchtypes;
+use App\Library\Util\SolrSearchQuery;
+
+/**
+ * Class for navigation in search results.
+ */
+class Navigation
+{
+
+    /**
+     * Builds query for Solr search.
+     * @return SolrSearchQuery|void
+     * @throws Application_Exception, Application_Util_BrowsingParamsException, Application_Util_QueryBuilderException
+     */
+    public static function getQueryUrl(\Illuminate\Http\Request $request) : SolrSearchQuery
+    {
+        $queryBuilder = new QueryBuilder();
+        $queryBuilderInput = $queryBuilder->createQueryBuilderInputFromRequest($request);
+
+        if (is_null($request->input('sortfield')) &&
+                ($request->input('browsing') === 'true' || $request->input('searchtype') === 'collection')) {
+            $queryBuilderInput['sortField'] = 'server_date_published';
+        }
+
+        if ($request->input('searchtype') === Searchtypes::LATEST_SEARCH) {
+            return $queryBuilder->createSearchQuery(self::validateInput($queryBuilderInput, 10, 100));
+        }
+
+        $solrSearchQuery = $queryBuilder->createSearchQuery(self::validateInput($queryBuilderInput, 1, 100));
+        return $solrSearchQuery;
+        //$queryBuilder->createSearchQuery(self::validateInput($queryBuilderInput,1, 100));
+    }
+
+    /**
+     * Adjust the actual rows parameter value if it is not between $min
+     * and $max (inclusive). In case the actual value is smaller (greater)
+     * than $min ($max) it is adjusted to $min ($max).
+     *
+     * Sets the actual start parameter value to 0 if it is negative.
+     *
+     * @param array $data An array that contains the request parameters.
+     * @param int $lowerBoundInclusive The lower bound.
+     * @param int $upperBoundInclusive The upper bound.
+     * @return int Returns the actual rows parameter value or an adjusted value if
+     * it is not in the interval [$lowerBoundInclusive, $upperBoundInclusive].
+     *
+     */
+    private static function validateInput(array $input, $min = 1, $max = 100) : array
+    {
+        if ($input['rows'] > $max) {
+            // $logger->warn("Values greater than $max are currently not allowed for the rows paramter.");
+            $input['rows'] = $max;
+        }
+        if ($input['rows'] < $min) {
+            // $logger->warn("rows parameter is smaller than $min: adjusting to $min.");
+            $input['rows'] = $min;
+        }
+        if ($input['start'] < 0) {
+            // $logger->warn("A negative start parameter is ignored.");
+            $input['start'] = 0;
+        }
+        return $input;
+    }
+}