Added comments.

Change-Id: I9222eb8da4eb018c48e3d2f29163195b343b6548
diff --git a/src/main/java/de/mannheim/ids/korap/sru/AnnotationLayer.java b/src/main/java/de/mannheim/ids/korap/sru/AnnotationLayer.java
index f79ffd8..10cdf53 100644
--- a/src/main/java/de/mannheim/ids/korap/sru/AnnotationLayer.java
+++ b/src/main/java/de/mannheim/ids/korap/sru/AnnotationLayer.java
@@ -5,42 +5,62 @@
 import java.util.List;
 import java.util.Map;
 
+/**
+ * This class contains properties of an annotation layer used for
+ * extracting and collecting annotations, as well as generating the
+ * advanced dataview in the SRU response.
+ * 
+ * Layer code is used to extract the annotations of the annotation
+ * layer from the match snippet in a KorAP MatchInfo response.
+ * 
+ * Annotation map collects the extracted annotations. Since a token or
+ * a text segment may have more than one annotation per annotation
+ * layer, the annotations are structured as a map whose keys are ids
+ * referring to the token positions.
+ * 
+ * @author margaretha
+ * 
+ */
 public class AnnotationLayer {
 
     public static enum TYPE {
         TEXT, POS, LEMMA;
-        
+
         public String toString() {
             return super.toString().toLowerCase();
         };
     }
-    
+
     private String layerCode;
     private URI layerId;
-    private Map<Integer,List<Annotation>> annotationMap;
-    
+    private Map<Integer, List<Annotation>> annotationMap;
+
     public AnnotationLayer (String layerCode, URI layerId) {
         this.layerCode = layerCode;
         this.layerId = layerId;
-        this.annotationMap = new HashMap<Integer,List<Annotation>>();
+        this.annotationMap = new HashMap<Integer, List<Annotation>>();
     }
+
     public String getLayerCode() {
         return layerCode;
     }
+
     public void setLayerCode(String layerCode) {
         this.layerCode = layerCode;
     }
 
-    public Map<Integer,List<Annotation>> getAnnotationMap() {
+    public Map<Integer, List<Annotation>> getAnnotationMap() {
         return annotationMap;
     }
-    public void setAnnotationMap(Map<Integer,List<Annotation>> annotationMap) {
+
+    public void setAnnotationMap(Map<Integer, List<Annotation>> annotationMap) {
         this.annotationMap = annotationMap;
     }
-    
+
     public URI getLayerId() {
         return layerId;
     }
+
     public void setLayerId(URI layerId) {
         this.layerId = layerId;
     }