SOLR-3670: New CountFieldValuesUpdateProcessorFactory (merge r1372687)

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_4x@1372689 13f79535-47bb-0310-9956-ffa450edef68

solr/CHANGES.txt

@@ -27,6 +27,15 @@ Upgrading from Solr 4.0.0-BETA
 
 In order to better support distributed search mode, the TermVectorComponent's response format has been changed so that if the schema defines a uniqueKeyField, then that field value is used as the "key" for each document in it's response section, instead of the internal lucene doc id.  Users w/o a uniqueKeyField will continue to see the same response format.  See SOLR-3229 for more details.
 
+Detailed Change List
+----------------------
+
+New Features
+----------------------
+
+* SOLR-3670: New CountFieldValuesUpdateProcessorFactory makes it easy to index 
+  the number of values in another field for later use at query time. (hossman)
+
 Optimizations
 ----------------------
 

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

@@ -0,0 +1,95 @@
+/*
+ * 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.update.processor;
+
+import org.apache.solr.core.SolrCore;
+import org.apache.solr.schema.IndexSchema;
+import org.apache.solr.schema.FieldType;
+import org.apache.solr.schema.SchemaField;
+import org.apache.solr.schema.TextField;
+import org.apache.solr.schema.StrField;
+
+import org.apache.solr.common.SolrInputField;
+import org.apache.solr.common.util.NamedList;
+import org.apache.solr.request.SolrQueryRequest;
+import org.apache.solr.response.SolrQueryResponse;
+
+import org.apache.commons.lang.StringUtils;
+
+/**
+ * <p>
+ * Replaces any list of values for a field matching the specified 
+ * conditions with the the count of the number of values for that field.
+ * </p>
+ * <p>
+ * By default, this processor matches no fields.
+ * </p>
+ * <p>
+ * The typical use case for this processor would be in combination with the 
+ * {@link CloneFieldUpdateProcessorFactory} so that it's possible to query by 
+ * the quantity of values in the source field.
+ * <p>
+ * For example, in the configuration below, the end result will be that the
+ * <code>category_count</code> field can be used to search for documents based 
+ * on how many values they contain in the <code>category</code> field.
+ * </p>
+ *
+ * <pre class="prettyprint">
+ * &lt;updateRequestProcessorChain&gt;
+ *   &lt;processor class="solr.CloneFieldUpdateProcessorFactory"&gt;
+ *     &lt;str name="source"&gt;category&lt;/str&gt;
+ *     &lt;str name="dest"&gt;category_count&lt;/str&gt;
+ *   &lt;/processor&gt;
+ *   &lt;processor class="solr.CountFieldValuesUpdateProcessorFactory"&gt;
+ *     &lt;str name="fieldName"&gt;category_count&lt;/str&gt;
+ *   &lt;/processor&gt;
+ *   &lt;processor class="solr.DefaultValueUpdateProcessorFactory"&gt;
+ *     &lt;str name="fieldName"&gt;category_count&lt;/str&gt;
+ *     &lt;int name="value"&gt;0&lt;/int&gt;
+ *   &lt;/processor&gt;
+ * &lt;/updateRequestProcessorChain&gt;
+ * </pre>
+ *
+ * <p>
+ * <b>NOTE:</b> The use of {@link DefaultValueUpdateProcessorFactory} is 
+ * important in this example to ensure that all documents have a value for the 
+ * <code>category_count</code> field, because 
+ * <code>CountFieldValuesUpdateProcessorFactory</code> only <i>replaces</i> the
+ * list of values with the size of that list.  If 
+ * <code>DefaultValueUpdateProcessorFactory</code> was not used, then any 
+ * document that had no values for the <code>category</code> field, would also 
+ * have no value in the <code>category_count</code> field.
+ * </p>
+ */
+public final class CountFieldValuesUpdateProcessorFactory extends FieldMutatingUpdateProcessorFactory {
+
+  @Override
+  public UpdateRequestProcessor getInstance(SolrQueryRequest req,
+                                            SolrQueryResponse rsp,
+                                            UpdateRequestProcessor next) {
+    return new FieldMutatingUpdateProcessor(getSelector(), next) {
+      protected SolrInputField mutate(final SolrInputField src) {
+        SolrInputField result = new SolrInputField(src.getName());
+        result.setValue(src.getValueCount(),
+                        src.getBoost());
+        return result;
+      }
+    };
+  }
+}
+

solr/core/src/test-files/solr/collection1/conf/solrconfig-update-processor-chains.xml

@@ -231,6 +231,12 @@
     </processor>
   </updateRequestProcessorChain>
 
+  <updateRequestProcessorChain name="count">
+    <processor class="solr.CountFieldValuesUpdateProcessorFactory">
+      <str name="fieldName">count_field</str>
+    </processor>
+  </updateRequestProcessorChain>
+
   <updateRequestProcessorChain name="ignore-not-in-schema">
     <processor class="solr.IgnoreFieldUpdateProcessorFactory" />
   </updateRequestProcessorChain>
@@ -344,6 +350,20 @@
     </processor>
   </updateRequestProcessorChain>
 
+  <updateRequestProcessorChain name="clone-then-count">
+    <processor class="solr.CloneFieldUpdateProcessorFactory">
+      <str name="source">category</str>
+      <str name="dest">category_count</str>
+    </processor>
+    <processor class="solr.CountFieldValuesUpdateProcessorFactory">
+      <str name="fieldName">category_count</str>
+    </processor>
+    <processor class="solr.DefaultValueUpdateProcessorFactory">
+      <str name="fieldName">category_count</str>
+      <int name="value">0</int>
+    </processor>
+  </updateRequestProcessorChain>
+
   <updateRequestProcessorChain name="regex-replace">
     <processor class="solr.RegexReplaceProcessorFactory">
       <str name="fieldName">content</str>

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

@@ -719,6 +719,58 @@ public void testCloneFieldExample() throws Exception {
     assertEquals(Arrays.asList(87, 78),
                  d.getFieldValues("all_prices"));
 
+  } 
+
+  public void testCountValues() throws Exception {
+
+    SolrInputDocument d = null;
+
+    // trivial 
+    d = processAdd("count",       
+                   doc(f("id", "1111"),
+                       f("count_field", "aaa", "bbb", "ccc")));
+
+    assertNotNull(d);
+    assertEquals(3, d.getFieldValue("count_field"));
+
+    // edge case: no values to count, means no count 
+    // (use default if you want one)
+    d = processAdd("count",       
+                   doc(f("id", "1111")));
+
+    assertNotNull(d);
+    assertFalse(d.containsKey("count_field"));
+
+    // typical usecase: clone and count 
+    d = processAdd("clone-then-count",       
+                   doc(f("id", "1111"),
+                       f("category", "scifi", "war", "space"),
+                       f("editors", "John W. Campbell"),
+                       f("list_price", 1000)));
+    assertNotNull(d);
+    assertEquals(Arrays.asList("scifi", "war", "space"),
+                 d.getFieldValues("category"));
+    assertEquals(3,
+                 d.getFieldValue("category_count"));
+    assertEquals(Arrays.asList("John W. Campbell"),
+                 d.getFieldValues("editors"));
+    assertEquals(1000,d.getFieldValue("list_price"));
+
+    // typical usecase: clone and count demonstrating default
+    d = processAdd("clone-then-count",       
+                   doc(f("id", "1111"),
+                       f("editors", "Anonymous"),
+                       f("list_price", 1000)));
+    assertNotNull(d);
+    assertEquals(0,
+                 d.getFieldValue("category_count"));
+    assertEquals(Arrays.asList("Anonymous"),
+                 d.getFieldValues("editors"));
+    assertEquals(1000,d.getFieldValue("list_price"));
+
+
+
+
   } 
 
   public void testCloneCombinations() throws Exception {