Factored audio parser tag processing

source/net/yacy/document/parser/audioTagParser.java

@@ -39,6 +39,7 @@ import java.util.Locale;
 import java.util.Map;
 import java.util.Set;
 
+import org.apache.commons.lang.StringUtils;
 import org.jaudiotagger.audio.AudioFile;
 import org.jaudiotagger.audio.AudioFileIO;
 import org.jaudiotagger.audio.SupportedFileFormat;
@@ -198,6 +199,8 @@ public class audioTagParser extends AbstractParser implements Parser {
 	
 	/** Map from each supported audio file extensions to a single audio media type */
 	private final Map<String, SupportedAudioMediaType> ext2NormalMediaType;
+	
+	private static final char SPACE_CHAR = ' ';
 
 	
     public audioTagParser() {
@@ -268,35 +271,12 @@ public class audioTagParser extends AbstractParser implements Parser {
             // text
             final List<String> descriptions = new ArrayList<String>(7);
             final StringBuilder text = new StringBuilder(500);
-            final char space = ' ';
             if(tag != null) {
-            	String field = tag.getFirst(FieldKey.ARTIST);
-            	descriptions.add(FieldKey.ARTIST.name() + ": " + field);
-            	text.append(field); text.append(space);
-            	
-            	field = tag.getFirst(FieldKey.ALBUM); 
-            	descriptions.add(FieldKey.ALBUM.name() + ": " + field);
-            	text.append(field); text.append(space);
-            	
-            	field = tag.getFirst(FieldKey.TITLE); 
-            	descriptions.add(FieldKey.TITLE.name() + ": " + field);
-            	text.append(field); text.append(space);
-            	
-            	field = tag.getFirst(FieldKey.COMMENT);
-            	descriptions.add(FieldKey.COMMENT.name() + ": " + field);
-            	text.append(field); text.append(space);
-            	
-            	field = tag.getFirst(FieldKey.LYRICS);
-            	descriptions.add(FieldKey.LYRICS.name() + ": " + field);
-            	text.append(field); text.append(space);
-            	
-            	field = tag.getFirst(FieldKey.TAGS);
-            	descriptions.add(FieldKey.TAGS.name() + ": " + field);
-            	text.append(field); text.append(space);
-            	
-            	field = tag.getFirst(FieldKey.GENRE);
-            	descriptions.add(FieldKey.GENRE.name() + ": " + field);
-            	text.append(field); text.append(space);
+				final FieldKey[] fieldsToProcess = new FieldKey[] { FieldKey.ARTIST, FieldKey.ALBUM, FieldKey.TITLE,
+						FieldKey.COMMENT, FieldKey.LYRICS, FieldKey.TAGS, FieldKey.GENRE };
+				for (final FieldKey field : fieldsToProcess) {
+					processTagField(field, tag, descriptions, text);
+				}
             }
             text.append(location.toTokens());
             
@@ -376,4 +356,27 @@ public class audioTagParser extends AbstractParser implements Parser {
 		}
         return docs;
     }
+
+	/**
+	 * Process a tag field : add its value to the descriptions and to text. All
+	 * parameters must not be null.
+	 * 
+	 * @param fieldKey
+	 *            a field key
+	 * @param tag
+	 *            a parsed audio tag
+	 * @param descriptions
+	 *            the document descriptions to fill
+	 * @param text
+	 *            the document text to fill
+	 */
+	private void processTagField(final FieldKey fieldKey, final Tag tag, final List<String> descriptions,
+			final StringBuilder text) {
+		final String fieldValue = tag.getFirst(fieldKey);
+		if(StringUtils.isNotBlank(fieldValue)) {
+			descriptions.add(fieldKey.name() + ": " + fieldValue);
+			text.append(fieldValue);
+			text.append(SPACE_CHAR);
+		}
+	}
 }