added code for querying the Content Service for static citation

pom.xml

@@ -8,7 +8,7 @@
     <groupId>org.reactome.web.pwp</groupId>
     <artifactId>model</artifactId>
     <packaging>jar</packaging>
-    <version>2.1.20-SNAPSHOT</version>
+    <version>2.1.21-SNAPSHOT</version>
     <name>Reactome Data Model</name>
 
     <description>

src/main/java/org/reactome/web/pwp/model/client/common/ContentClientHandler.java

@@ -42,4 +42,9 @@ interface AncestorsLoaded extends ContentClientHandler {
     interface DatabaseInfo extends ContentClientHandler {
         void onDatabaseInfoLoaded(DBInfo dbInfo);
     }
+
+    interface Citation extends ContentClientHandler {
+        void onCitationTextLoaded(String citation);
+    }
+
 }

src/main/java/org/reactome/web/pwp/model/client/content/ContentClient.java

@@ -175,4 +175,11 @@ public static void getDatabaseInformation(ContentClientHandler.DatabaseInfo hand
             });
         }
     }
+
+    public static void getStaticCitation(String id, ContentClientHandler.Citation handler) {
+        request("citation/static/" + id, Accept.TEXT_PLAIN, handler, body -> {
+            String citation = body;
+            handler.onCitationTextLoaded(citation);
+        });
+    }
 }

src/main/java/org/reactome/web/pwp/model/test/WidgetTest.java

@@ -31,6 +31,7 @@ public void onModuleLoad() {
             addDatabaseName();
             addSpecies();
             addTopLvelPathway();
+            getCitation("31691815");
 //                //RAF/MAP -> 109869 (for v52)
 //                DatabaseObjectFactory.get(109869L, new DatabaseObjectCreatedHandler() {
 //                    @Override
@@ -147,4 +148,27 @@ public void onContentClientError(ContentClientError error) {
             }
         });
     }
+
+    private void getCitation(String id) {
+        ContentClient.getStaticCitation(id, new ContentClientHandler.Citation() {
+            @Override
+            public void onCitationTextLoaded(String citation) {
+                container.add(new Label(citation));
+            }
+
+            @Override
+            public void onContentClientException(Type type, String message) {
+                container.add(new Label("in content client exception"));
+                container.add(new Label(type.toString()));
+                container.add(new Label(message));
+            }
+
+            @Override
+            public void onContentClientError(ContentClientError error) {
+                container.add(new Label("in content client error"));
+                container.add(new Label(error.toString()));
+            }
+        });
+    }
+
 }