SOLR-376: hl.alternateField

git-svn-id: https://svn.apache.org/repos/asf/lucene/solr/trunk@583979 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -87,8 +87,9 @@ New Features
 13. SOLR-225: Enable pluggable highlighting classes.  Allow configurable
     highlighting formatters and Fragmenters.  (ryan)
 
-14. SOLR-273: Added hl.maxAnalyzedChars highlighting parameter, defaulting to
-    50k (klaas)
+14. SOLR-273/376: Added hl.maxAnalyzedChars highlighting parameter, defaulting to
+    50k.  Also add hl.alternateField, which allows the specification of a backup
+    field to use as summary if no keywords are matched. (klaas)
 
 15. SOLR-291: Control maximum number of documents to cache for any entry
     in the queryResultCache via queryResultMaxDocsCached solrconfig.xml 
@@ -134,7 +135,6 @@ New Features
 25. SOLR-359: Add field type className to Luke response, and enabled access
     to the detailed field information from the solrj client API.
     (Grant Ingersoll via ehatcher)
-    
 
 Changes in runtime behavior
 

src/java/org/apache/solr/common/params/HighlightParams.java

@@ -31,6 +31,7 @@ public interface HighlightParams {
   public static final String FORMATTER   = HIGHLIGHT+".formatter";
   public static final String FRAGMENTER  = HIGHLIGHT+".fragmenter";
   public static final String FIELD_MATCH = HIGHLIGHT+".requireFieldMatch";
+  public static final String ALTERNATE_FIELD = HIGHLIGHT+".alternateField";
 
   // Formatter
   public static final String SIMPLE = "simple";

src/java/org/apache/solr/highlight/SolrHighlighter.java

@@ -275,7 +275,7 @@ public class SolrHighlighter
            Highlighter highlighter = getHighlighter(query, fieldName, req);
            int numFragments = getMaxSnippets(fieldName, params);
 
-           String[] summaries;
+           String[] summaries = null;
            TextFragment[] frag;
            if (docTexts.length == 1) {
               // single-valued field
@@ -309,6 +309,16 @@ public class SolrHighlighter
               if (summaries.length > 0) 
                 docSummaries.add(fieldName, summaries);
            }
+           // no summeries made, copy text from alternate field
+           if (summaries == null || summaries.length == 0) {
+              String alternateField = req.getParams().getFieldParam(fieldName, HighlightParams.ALTERNATE_FIELD);
+              if (alternateField != null && alternateField.length() > 0) {
+                 String[] altTexts = doc.getValues(alternateField);
+                    if (altTexts != null && altTexts.length > 0)
+                       docSummaries.add(fieldName, altTexts);
+              }
+           }
+ 
         }
         String printId = schema.printableUniqueKey(doc);
         fragments.add(printId == null ? null : printId, docSummaries);

src/test/org/apache/solr/highlight/HighlighterTest.java

@@ -387,4 +387,36 @@ public class HighlighterTest extends AbstractSolrTestCase {
            "//lst[@name='1']/arr[@name='tv_text']/str[.='a <em>long</em> days night this should be a piece of text which is is is is is is is is is is is is is is is is is is is is is is is is isis is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is sufficiently lengthly to produce multiple fragments which are not concatenated at all']"
            );
   }
+  public void testAlternateSummary() {
+     //long document
+     assertU(adoc("tv_text", "keyword is only here",
+                  "t_text", "a piece of text to be substituted",
+                  "id", "1"));
+     assertU(commit());
+     assertU(optimize());
+
+    // do summarization
+    HashMap<String,String> args = new HashMap<String,String>();
+    args.put("hl", "true");
+    args.put("hl.fragsize","0");
+    args.put("hl.fl", "t_text");
+    TestHarness.LocalRequestFactory sumLRF = h.getRequestFactory(
+      "standard", 0, 200, args);
+
+    // no alternate
+    assertQ("Alternate summarization",
+            sumLRF.makeRequest("tv_text:keyword"),
+            "//lst[@name='highlighting']/lst[@name='1']",
+            "//lst[@name='highlighting']/lst[@name='1' and count(*)=0]"
+            );
+
+    // with an alternate
+    args.put("hl.alternateField", "id");
+    sumLRF = h.getRequestFactory("standard", 0, 200, args);
+    assertQ("Alternate summarization",
+            sumLRF.makeRequest("tv_text:keyword"),
+            "//lst[@name='highlighting']/lst[@name='1' and count(*)=1]",
+            "//lst[@name='highlighting']/lst[@name='1']/arr[@name='t_text']/str[.='1']"
+            );
+  }
 }