JAVA-2665: Add DochubTaglet to support links from Javadoc to http://dochub.mongodb.org

Author: jyemin

build.gradle

@@ -116,6 +116,7 @@ configure(subprojects.findAll { it.name != 'util' }) {
         options.links 'http://docs.oracle.com/javase/7/docs/api/'
         options.tagletPath single(project(':util').sourceSets.main.output.classesDirs)
         options.taglets 'ManualTaglet'
+        options.taglets 'DochubTaglet'
         options.taglets 'ServerReleaseTaglet'
         options.encoding = 'UTF-8'
         options.charSet 'UTF-8'

util/src/main/DochubTaglet.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright 2017 MongoDB, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import com.sun.tools.doclets.Taglet;
+
+import java.util.Map;
+
+public class DochubTaglet extends DocTaglet {
+
+    public static void register(final Map<String, Taglet> tagletMap) {
+        DochubTaglet t = new DochubTaglet();
+        tagletMap.put(t.getName(), t);
+    }
+
+    public String getName() {
+        return "mongodb.driver.dochub";
+    }
+
+    @Override
+    protected String getHeader() {
+        return "MongoDB documentation";
+    }
+
+    @Override
+    protected String getBaseDocURI() {
+        return "http://dochub.mongodb.org/";
+    }
+
+}