PortMapper: Add convenience methods

core/java/src/net/i2p/util/PortMapper.java

@@ -114,6 +114,15 @@ public class PortMapper {
         return _dir.putIfAbsent(service, InetSocketAddress.createUnresolved(host, port)) == null;
     }
 
+    /**
+     *  Is the service registered?
+     *
+     *  @since 0.9.34
+     */
+    public boolean isRegistered(String service) {
+        return _dir.containsKey(service);
+    }
+
     /**
      *  Remove the service
      */
@@ -121,6 +130,18 @@ public class PortMapper {
         _dir.remove(service);
     }
 
+    /**
+     *  Remove the service,
+     *  only if it is registered with the supplied port.
+     *
+     *  @since 0.9.34
+     */
+    public void unregister(String service, int port) {
+        // not synched
+        if (getPort(service) == port)
+            _dir.remove(service);
+    }
+
     /**
      *  Get the registered port for a service
      *  @return -1 if not registered