SOLR-516: add hl.maxAlternateFieldLength

git-svn-id: https://svn.apache.org/repos/asf/lucene/solr/trunk@646926 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -111,11 +111,11 @@ New Features
 13. SOLR-225: Enable pluggable highlighting classes.  Allow configurable
     highlighting formatters and Fragmenters.  (ryan)
 
-14. SOLR-273/376/452: Added hl.maxAnalyzedChars highlighting parameter, defaulting 
+14. SOLR-273/376/452/516: Added hl.maxAnalyzedChars highlighting parameter, defaulting 
     to 50k, hl.alternateField, which allows the specification of a backup
     field to use as summary if no keywords are matched, and hl.mergeContiguous,
     which combines fragments if they are adjacent in the source document.
-    (klaas, Grant Ingersoll via klaas)
+    (klaas, Grant Ingersoll, Koji Sekiguchi via klaas)
 
 15. SOLR-291: Control maximum number of documents to cache for any entry
     in the queryResultCache via queryResultMaxDocsCached solrconfig.xml 

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

@@ -32,6 +32,7 @@ public interface HighlightParams {
   public static final String FRAGMENTER  = HIGHLIGHT+".fragmenter";
   public static final String FIELD_MATCH = HIGHLIGHT+".requireFieldMatch";
   public static final String ALTERNATE_FIELD = HIGHLIGHT+".alternateField";
+  public static final String ALTERNATE_FIELD_LENGTH = HIGHLIGHT+".maxAlternateFieldLength";
 
   public static final String MERGE_CONTIGUOUS_FRAGMENTS = HIGHLIGHT + ".mergeContiguous";
   // Formatter

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

@@ -23,6 +23,7 @@ import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.LinkedList;
+import java.util.List;
 import java.util.ListIterator;
 import java.util.Map;
 import java.util.Set;
@@ -274,9 +275,24 @@ public class DefaultSolrHighlighter extends SolrHighlighter
               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)
+                if (altTexts != null && altTexts.length > 0){
+                  int alternateFieldLen = req.getParams().getFieldInt(fieldName, HighlightParams.ALTERNATE_FIELD_LENGTH,0);
+                  if( alternateFieldLen <= 0 ){
                     docSummaries.add(fieldName, altTexts);
                   }
+                  else{
+                    List<String> altList = new ArrayList<String>();
+                    int len = 0;
+                    for( String altText: altTexts ){
+                      altList.add( len + altText.length() > alternateFieldLen ?
+                                   altText.substring( 0, alternateFieldLen - len ) : altText );
+                      len += altText.length();
+                      if( len >= alternateFieldLen ) break;
+                    }
+                    docSummaries.add(fieldName, altList);
+                  }
+                }
+              }
            }
  
         }

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

@@ -470,5 +470,15 @@ public class HighlighterTest extends AbstractSolrTestCase {
             "//lst[@name='highlighting']/lst[@name='1' and count(*)=1]",
             "//lst[@name='highlighting']/lst[@name='1']/arr[@name='t_text']/str[.='1']"
             );
+
+    // with an alternate + max length
+    args.put("hl.alternateField", "t_text");
+    args.put("hl.maxAlternateFieldLength", "15");
+    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[.='a piece of text']"
+            );
   }
 }