openflowplugin/src/main/java/org/opendaylight/openflowplugin/openflow/md/core/sal/convertor/common/OrderComparator.java

   1 package org.opendaylight.openflowplugin.openflow.md.core.sal.convertor.common;
   2
   3 import org.opendaylight.yang.gen.v1.urn.opendaylight.action.types.rev131112.Ordered;
   4
   5 import java.util.Comparator;
   6
   7 /**
   8  * Comparator for comparing objects which extend Ordered.
   9  *
  10  * @param <T>
  11  */
  12 public class OrderComparator<T extends Ordered> implements Comparator<T> {
  13
  14     private static OrderComparator instance = new OrderComparator();
  15     public static OrderComparator build() {
  16         return instance;
  17     }
  18
  19     @Override
  20     public int compare(T obj1, T obj2) {
  21         if(obj1 ==null || obj2==null ) {
  22             throw new NullPointerException("Cannot compare null Actions");
  23         } else if (obj1.getOrder() == null) {
  24             throw new NullPointerException(errorMsg(obj1));
  25         } else if (obj2.getOrder() == null) {
  26             throw new NullPointerException(errorMsg(obj2));
  27         }
  28         return obj1.getOrder().compareTo(obj2.getOrder());
  29     }
  30
  31     private String errorMsg(T obj) {
  32         return "The comparing model " + obj + "has getOrder() == null. An order is mandatory";
  33     }
  34 }