LUCENE-6087: allow custom DirectoryReader to SearcherManager

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1642887 13f79535-47bb-0310-9956-ffa450edef68

lucene/CHANGES.txt

@@ -233,6 +233,9 @@ API Changes
   resourceDescription so its toString is sane (Robert Muir, Mike
   McCandless)
 
+* LUCENE-6087: Allow passing custom DirectoryReader to SearcherManager
+  (Mike McCandless)
+
 Bug Fixes
 
 * LUCENE-5650: Enforce read-only access to any path outside the temporary

lucene/core/src/java/org/apache/lucene/search/SearcherManager.java

@@ -106,6 +106,25 @@ public final class SearcherManager extends ReferenceManager<IndexSearcher> {
     current = getSearcher(searcherFactory, DirectoryReader.open(dir));
   }
 
+  /**
+   * Creates and returns a new SearcherManager from an existing {@link DirectoryReader}.  Note that
+   * this steals the incoming reference.
+   *
+   * @param reader the DirectoryReader.
+   * @param searcherFactory An optional {@link SearcherFactory}. Pass
+   *        <code>null</code> if you don't require the searcher to be warmed
+   *        before going live or other custom behavior.
+   *        
+   * @throws IOException if there is a low-level I/O error
+   */
+  public SearcherManager(DirectoryReader reader, SearcherFactory searcherFactory) throws IOException {
+    if (searcherFactory == null) {
+      searcherFactory = new SearcherFactory();
+    }
+    this.searcherFactory = searcherFactory;
+    this.current = getSearcher(searcherFactory, reader);
+  }
+
   @Override
   protected void decRef(IndexSearcher reference) throws IOException {
     reference.getIndexReader().decRef();

lucene/core/src/test/org/apache/lucene/search/TestSearcherManager.java

@@ -31,16 +31,20 @@ import org.apache.lucene.analysis.MockAnalyzer;
 import org.apache.lucene.document.Document;
 import org.apache.lucene.index.ConcurrentMergeScheduler;
 import org.apache.lucene.index.DirectoryReader;
+import org.apache.lucene.index.FilterDirectoryReader;
+import org.apache.lucene.index.FilterLeafReader;
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.IndexWriter;
 import org.apache.lucene.index.IndexWriterConfig;
+import org.apache.lucene.index.LeafReader;
+import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.index.RandomIndexWriter;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.index.ThreadedIndexingAndSearchingTestCase;
 import org.apache.lucene.store.AlreadyClosedException;
 import org.apache.lucene.store.Directory;
-import org.apache.lucene.util.LuceneTestCase;
 import org.apache.lucene.util.LuceneTestCase.SuppressCodecs;
+import org.apache.lucene.util.LuceneTestCase;
 import org.apache.lucene.util.NamedThreadFactory;
 import org.apache.lucene.util.TestUtil;
 
@@ -445,5 +449,51 @@ public class TestSearcherManager extends ThreadedIndexingAndSearchingTestCase {
     sm.close();
     dir.close();
   }
-  
+
+  private static class MyFilterLeafReader extends FilterLeafReader {
+    public MyFilterLeafReader(LeafReader in) {
+      super(in);
+    }
+  }
+
+  private static class MyFilterDirectoryReader extends FilterDirectoryReader {
+    public MyFilterDirectoryReader(DirectoryReader in) {
+      super(in, 
+            new FilterDirectoryReader.SubReaderWrapper() {
+              @Override
+              public LeafReader wrap(LeafReader reader) {
+                return new MyFilterLeafReader(reader);
+              }
+            });
+    }
+
+    @Override
+    protected DirectoryReader doWrapDirectoryReader(DirectoryReader in) {
+      return new MyFilterDirectoryReader(in);
+    }
+  }
+
+  // LUCENE-6087
+  public void testCustomDirectoryReader() throws Exception {
+    Directory dir = newDirectory();
+    RandomIndexWriter w = new RandomIndexWriter(random(), dir);
+    DirectoryReader reader = new MyFilterDirectoryReader(w.getReader());
+    SearcherManager mgr = new SearcherManager(reader, null);
+    for(int i=0;i<10;i++) {
+      w.addDocument(new Document());
+      mgr.maybeRefresh();
+      IndexSearcher s = mgr.acquire();
+      try {
+        assertTrue(s.getIndexReader() instanceof MyFilterDirectoryReader);
+        for (LeafReaderContext ctx : s.getIndexReader().leaves()) {
+          assertTrue(ctx.reader() instanceof MyFilterLeafReader);
+        }
+      } finally {
+        mgr.release(s);
+      }
+    }
+    mgr.close();
+    w.close();
+    dir.close();
+  }
 }