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  1. Solr
  2. SOLR-12374

Add SolrCore.withSearcher(lambda accepting SolrIndexSearcher)

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    Details

    • Type: Improvement
    • Status: Closed
    • Priority: Minor
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: 7.4
    • Component/s: None
    • Labels:
      None

      Description

      I propose adding the following to SolrCore:

        /**
         * Executes the lambda with the {@link SolrIndexSearcher}.  This is more convenience than using
         * {@link #getSearcher()} since there is no ref-counting business to worry about.
         * Example:
         * <pre class="prettyprint">
         *   IndexReader reader = h.getCore().withSearcher(SolrIndexSearcher::getIndexReader);
         * </pre>
         */
        @SuppressWarnings("unchecked")
        public <R> R withSearcher(Function<SolrIndexSearcher,R> lambda) {
          final RefCounted<SolrIndexSearcher> refCounted = getSearcher();
          try {
            return lambda.apply(refCounted.get());
          } finally {
            refCounted.decref();
          }
        }
      

      This is a nice tight convenience method, avoiding the clumsy RefCounted API which is easy to accidentally incorrectly use – see https://issues.apache.org/jira/browse/SOLR-11616?focusedCommentId=16477719&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#comment-16477719

      I guess my only (small) concern is if hypothetically you might make the lambda short because it's easy to do that (see the one-liner example above) but the object you return that you're interested in  (say IndexReader) could potentially become invalid if the SolrIndexSearcher closes.  But I think/hope that's impossible normally based on when this getSearcher() used?  I could at least add a warning to the docs.

        Attachments

        1. SOLR-12374.patch
          75 kB
          David Smiley

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            • Assignee:
              dsmiley David Smiley
              Reporter:
              dsmiley David Smiley
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              • Created:
                Updated:
                Resolved: