java避免使用重写注释编写重复的代码

Question

下面是别人在我们公司写的课

public class Reader1 extends PdsxAdapterBaseGemsReader {

    @Override
    public PdsxReader acquireReader(PdsxReadRequest pdsxReadRequest) {
       return new PdsxUserReadOnlyGemsReader(pdsxReadRequest);
    }

    protected static class PdsxUserReadOnlyGemsReader extends PdsxAdapterBaseGemsReader.PdsxBaseGemsReader {

           protected PdsxUserReadOnlyGemsReader(PdsxReadRequest pdsxReadRequest) {
              super(pdsxReadRequest);
           }

           protected ClusterIdEnum getClusterId() {
              return ClusterIdEnum.MARKEPLACE1;
           }

           @Override
           public List<PdsxRecord> readData() {
               List<UserCacheDoImpl> userDos = readUserCacheRecords(req, serverId,startLastModifiedDate, endLastModifiedDate);
               // some code
           }


           private List<UserCacheDoImpl> readUserCacheRecords(PdsxReadRequest req, int serverId, Date startLastModifiedDate, Date endLastModifiedDate) {
              List<UserCacheDoImpl> userDos = new ArrayList<UserCacheDoImpl>();
              BackEndIterator userIter = new BackEndIterator(getClusterId().getId(), serverId, startLastModifiedDate, endLastModifiedDate, READ_BATCH_SIZE);
              //some code
           }


           private PdsxRecord createPdsxRecordFromUserDO(UserCacheDoImpl userCache) {
              //some code
           }

           private void xValidateAttrKey(PdsxAttrKey readAttr) {
              // some code
           }
    }

}

问题陈述：-

我需要编写另一个具有相同功能的类，并使用所有方法名。唯一的区别是这种方法的不同-

protected ClusterIdEnum getClusterId() {
    return ClusterIdEnum.MARKEPLACE1;
}

这是必须的

protected ClusterIdEnum getClusterId() {
    return ClusterIdEnum.MARKEPLACE2;
}

因此，如果我需要用一种非常老式的方式来做，我可以复制粘贴第一个Reader类中的所有内容，并通过更改cluster id方法来创建一个新的Reader2类。这就是全部。但这不是一个好办法

有谁能告诉我，做同样的事情最好的方法是什么而不用写很多次

我是这样想的，用类似这样的代码重写基类中的getLcusterId() method-

public class Reader2 extends Reader1 {

    @Override
    public PdsxReader acquireReader(PdsxReadRequest pdsxReadRequest) {
       return new PdsxUserNewReadOnlyGemsReader(pdsxReadRequest);
    }

    protected static class PdsxUserNewReadOnlyGemsReader extends PdsxUserReadOnlyGemsReader {

       protected PdsxUserNewReadOnlyGemsReader(PdsxReadRequest pdsxReadRequest) {
          super(pdsxReadRequest);
       }

       @Override
       protected ClusterIdEnum getClusterId() {
          return ClusterIdEnum.MARKEPLACE2;
       }
    }
}

因为第一个类中的所有内容都是相同的，所以我不需要在Reader2类中实现任何内容，对吗？只是我可以覆盖getClusterId() method

如果我遗漏了什么，请告诉我

Answer 1

如果可以修改acquireReader方法的签名，您可以向reader类添加一个字段：

public class Reader1 extends PdsxAdapterBaseGemsReader {

@Override
public PdsxReader acquireReader(PdsxReadRequest pdsxReadRequest, ClusterIdEnum clusterId) {
   return new PdsxUserReadOnlyGemsReader(pdsxReadRequest, clusterId);
}

protected static class PdsxUserReadOnlyGemsReader extends PdsxAdapterBaseGemsReader.PdsxBaseGemsReader {
       private ClusterIdEnum clusterId;

       protected PdsxUserReadOnlyGemsReader(PdsxReadRequest pdsxReadRequest, ClusterIdEnum clusterId) {
          super(pdsxReadRequest);
          this.clusterId = clusterId;
       }

       protected ClusterIdEnum getClusterId() {
          return clusterId;
       }

       //...
}

或者，您可以将其添加到Reader1构造函数中，但也可以在创建reader对象时传递clusterId：

public class Reader1 extends PdsxAdapterBaseGemsReader {
       private ClusterIdEnum clusterId;

       public Reader1 (ClusterIdEnum clusterId) {
          this.clusterId = clusterId;
       }

       @Override
       public PdsxReader acquireReader(PdsxReadRequest pdsxReadRequest) {
          return new PdsxUserReadOnlyGemsReader(pdsxReadRequest, clusterId);
       }

protected static class PdsxUserReadOnlyGemsReader extends PdsxAdapterBaseGemsReader.PdsxBaseGemsReader {
       private ClusterIdEnum clusterId;

       protected PdsxUserReadOnlyGemsReader(PdsxReadRequest pdsxReadRequest, ClusterIdEnum clusterId) {
          super(pdsxReadRequest);
          this.clusterId = clusterId;
       }

       protected ClusterIdEnum getClusterId() {
          return clusterId;
       }

       //...
}