SOLR-938 -- Add event listener API for import start and end

git-svn-id: https://svn.apache.org/repos/asf/lucene/solr/trunk@732695 13f79535-47bb-0310-9956-ffa450edef68

contrib/dataimporthandler/CHANGES.txt

@@ -47,6 +47,9 @@ New Features
 9. SOLR-910:  Add a few utility commands to the DIH admin page such as full import, delta import, status, reload config.
               (Ahmed Hammad via shalin)
 
+10.SOLR-938:  Add event listener API for import start and end.
+              (Kay Kay, Noble Paul via shalin)
+
 Optimizations
 ----------------------
 1. SOLR-846:  Reduce memory consumption during delta import by removing keys when used

contrib/dataimporthandler/src/main/java/org/apache/solr/handler/dataimport/DataConfig.java

@@ -57,11 +57,15 @@ public class DataConfig {
 
     public List<Entity> entities = new ArrayList<Entity>();
 
+    public String onImportStart, onImportEnd;
+
     public Document() {
     }
 
     public Document(Element element) {
       this.deleteQuery = getStringAttribute(element, "deleteQuery", null);
+      this.onImportStart = getStringAttribute(element, "onImportStart", null);
+      this.onImportEnd = getStringAttribute(element, "onImportEnd", null);
       List<Element> l = getChildNodes(element, "entity");
       for (Element e : l)
         entities.add(new Entity(e));

contrib/dataimporthandler/src/main/java/org/apache/solr/handler/dataimport/DocBuilder.java

@@ -92,6 +92,21 @@ public class DocBuilder {
     return resolver;
   }
 
+  private void invokeEventListener(String className) {
+    try {
+      EventListener listener = (EventListener) loadClass(className, dataImporter.getCore()).newInstance();
+      int currentProcess = -1;
+      if (dataImporter.getStatus() == DataImporter.Status.RUNNING_DELTA_DUMP) {
+        currentProcess = Context.DELTA_DUMP;
+      } else  {
+        currentProcess = Context.FULL_DUMP;
+      }
+      listener.onEvent(new ContextImpl(null, getVariableResolver(), null, currentProcess, session, null, this));
+    } catch (Exception e) {
+      DataImportHandlerException.wrapAndThrow(DataImportHandlerException.SEVERE, e, "Unable to load class : " + className);
+    }
+  }
+
   @SuppressWarnings("unchecked")
   public void execute() {
     dataImporter.store(DataImporter.STATUS_MSGS, statusMessages);
@@ -114,6 +129,11 @@ public class DocBuilder {
 
     List<String> entities = requestParameters.entities;
 
+    // Trigger onImportStart
+    if (document.onImportStart != null) {
+      invokeEventListener(document.onImportStart);
+    }
+
     for (DataConfig.Entity e : document.entities) {
       if (entities != null && !entities.contains(e.name))
         continue;
@@ -137,10 +157,16 @@ public class DocBuilder {
       } else if (requestParameters.commit) {
         // Debug mode, commit if commit=true was specified
         commit();
+        if (document.onImportEnd != null) {
+          invokeEventListener(document.onImportEnd);
+        }
       }
     } else {
       // Finished operation normally, commit now
       commit();
+      if (document.onImportEnd != null) {
+        invokeEventListener(document.onImportEnd);
+      }
     }
 
     statusMessages.remove(TIME_ELAPSED);

contrib/dataimporthandler/src/main/java/org/apache/solr/handler/dataimport/EventListener.java

@@ -0,0 +1,36 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.solr.handler.dataimport;
+
+/**
+ * Event listener for DataImportHandler
+ *
+ * <b>This API is experimental and subject to change</b>
+ *
+ * @version $Id$
+ * @since solr 1.4
+ */
+public abstract class EventListener {
+
+  /**
+   * Event callback
+   *
+   * @param ctx the Context in which this event was called
+   */
+  public abstract void onEvent(Context ctx);
+
+}

contrib/dataimporthandler/src/test/java/org/apache/solr/handler/dataimport/TestDocBuilder2.java

@@ -78,6 +78,8 @@ public class TestDocBuilder2 extends AbstractDataImportHandlerTest {
     super.runFullImport(dataConfigWithCaseInsensitiveFields);
 
     assertQ(req("id:1"), "//*[@numFound='1']");
+    assertTrue("Start event listener was not called", StartEventListener.executed);
+    assertTrue("End event listener was not called", EndEventListener.executed);
   }
 
   @Test
@@ -137,6 +139,22 @@ public class TestDocBuilder2 extends AbstractDataImportHandlerTest {
 
   }
 
+  public static class StartEventListener extends EventListener {
+    public static boolean executed = false;
+
+    public void onEvent(Context ctx) {
+      executed = true;
+    }
+  }
+
+  public static class EndEventListener extends EventListener {
+    public static boolean executed = false;
+
+    public void onEvent(Context ctx) {
+      executed = true;
+    }
+  }
+
   private final String requestParamAsVariable = "<dataConfig>\n" +
           "    <dataSource type=\"MockDataSource\" />\n" +
           "    <document>\n" +
@@ -158,7 +176,7 @@ public class TestDocBuilder2 extends AbstractDataImportHandlerTest {
           "</dataConfig>";
 
   private final String dataConfigWithCaseInsensitiveFields = "<dataConfig>\n" +
-          "    <document>\n" +
+          "    <document onImportStart=\"TestDocBuilder2$StartEventListener\" onImportEnd=\"TestDocBuilder2$EndEventListener\">\n" +
           "        <entity name=\"books\" query=\"select * from x\">\n" +
           "            <field column=\"ID\" />\n" +
           "            <field column=\"Desc\" />\n" +