SOLR-5395: add RunAlways marker interface for update processor facctories

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1536341 13f79535-47bb-0310-9956-ffa450edef68

solr/CHANGES.txt

@@ -103,6 +103,11 @@ New Features
 * SOLR-5027: CollapsingQParserPlugin for high performance field collapsing on high cardinality fields.
   (Joel Bernstein)
 
+* SOLR-5395: Added a RunAlways marker interface for UpdateRequestProcessorFactory 
+  implementations indicating that they should not be removed in later stages
+  of distributed updates (usually signalled by the update.distrib parameter)
+  (yonik)
+  
 
 Bug Fixes
 ----------------------

solr/core/src/java/org/apache/solr/update/processor/UpdateRequestProcessorChain.java

@@ -75,7 +75,7 @@ import java.util.ArrayList;
  * <code>UpdateRequestProcessorFactory</code>.  If a chain includes 
  * <code>RunUpdateProcessorFactory</code> but does not include a 
  * <code>DistributingUpdateProcessorFactory</code>, it will be added 
- * automaticly by {@link #init init()}.
+ * automatically by {@link #init init()}.
  * </p>
  *
  * @see UpdateRequestProcessorFactory
@@ -195,8 +195,8 @@ public final class UpdateRequestProcessorChain implements PluginInfoInitialized
           if (factory instanceof DistributingUpdateProcessorFactory) {
             afterDistrib = false;
           }
-        } else if (!(factory instanceof LogUpdateProcessorFactory)) {    // TODO: use a marker interface for this?
+        } else if (!(factory instanceof UpdateRequestProcessorFactory.RunAlways)) {
-          // skip anything that is not the log factory
+          // skip anything that doesn't have the marker interface
           continue;
         }
       }

solr/core/src/java/org/apache/solr/update/processor/UpdateRequestProcessorFactory.java

@@ -34,6 +34,13 @@ import org.apache.solr.util.plugin.SolrCoreAware;
  */
 public abstract class UpdateRequestProcessorFactory implements NamedListInitializedPlugin
 {
+
+  /** A marker interface for UpdateRequestProcessorFactory implementations indicating that
+   * the factory should be used even if the update.distrib parameter would otherwise cause
+   * it to not be run.
+   */
+  public interface RunAlways {}
+
   @Override
   public void init( NamedList args )
   {

solr/core/src/test-files/solr/collection1/conf/solrconfig-transformers.xml

@@ -62,6 +62,7 @@
 <updateRequestProcessorChain name="distrib-chain-explicit">
   <!-- explicit test using processors before and after distrib -->
   <processor class="solr.CustomUpdateRequestProcessorFactory" />
+  <processor class="solr.LogUpdateProcessorFactory" />
   <processor class="solr.DistributedUpdateProcessorFactory" />
   <processor class="solr.RemoveBlankFieldUpdateProcessorFactory" />
   <processor class="solr.RunUpdateProcessorFactory" />
@@ -69,6 +70,7 @@
 <updateRequestProcessorChain name="distrib-chain-implicit">
   <!-- implicit test w/o distrib declared -->
   <processor class="solr.CustomUpdateRequestProcessorFactory" />
+  <processor class="solr.LogUpdateProcessorFactory" />
   <processor class="solr.RemoveBlankFieldUpdateProcessorFactory" />
   <!-- distrib should be injected here -->
   <processor class="solr.RunUpdateProcessorFactory" />
@@ -76,6 +78,7 @@
 <updateRequestProcessorChain name="distrib-chain-noop">
   <!-- explicit test using noop distrib -->
   <processor class="solr.CustomUpdateRequestProcessorFactory" />
+  <processor class="solr.LogUpdateProcessorFactory" />
   <processor class="solr.NoOpDistributingUpdateProcessorFactory" />
   <processor class="solr.RemoveBlankFieldUpdateProcessorFactory" />
   <processor class="solr.RunUpdateProcessorFactory" />

solr/core/src/test/org/apache/solr/update/processor/UpdateRequestProcessorFactoryTest.java

@@ -78,7 +78,7 @@ public class UpdateRequestProcessorFactoryTest extends AbstractSolrTestCase {
       assertNotNull(name, chain);
 
       // either explicitly, or because of injection
-      assertEquals(name + " chain length", 4,
+      assertEquals(name + " chain length", 5,
                    chain.getFactories().length);
 
       // Custom comes first in all three of our chains
@@ -94,6 +94,19 @@ public class UpdateRequestProcessorFactoryTest extends AbstractSolrTestCase {
                  + proc.getClass().getName(),
                  proc instanceof CustomUpdateRequestProcessor);
 
+      int n=0;
+      boolean foundLog = false;
+      for (;;) {
+        n++;
+        if (proc instanceof LogUpdateProcessor) {
+          foundLog = true;
+        }
+        proc = proc.next;
+        if (proc == null) break;
+      }
+
+      assertTrue( n < chain.getFactories().length );   // some processors should have been dropped
+      assertTrue( foundLog );  // make sure the marker interface was successful in keeping the log processor
 
     }