address code review comments

Author: karthikkondapally

examples/src/main/java/io/kubernetes/client/examples/PagerExample.java

@@ -9,7 +9,7 @@
 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.
-*/
+ */
 package io.kubernetes.client.examples;
 
 import io.kubernetes.client.ApiClient;
@@ -18,8 +18,8 @@
 import io.kubernetes.client.models.V1Namespace;
 import io.kubernetes.client.models.V1NamespaceList;
 import io.kubernetes.client.pager.Pager;
+import io.kubernetes.client.pager.PagerParams;
 import io.kubernetes.client.util.Config;
-import io.kubernetes.client.util.PagerParams;
 import java.io.IOException;
 import java.util.List;
 import java.util.concurrent.TimeUnit;
@@ -41,7 +41,7 @@ public static void main(String[] args) throws IOException {
     CoreV1Api api = new CoreV1Api();
     int i = 0;
     Pager pager =
-        new Pager(
+        new Pager<V1Namespace, V1NamespaceList>(
             (PagerParams param) -> {
               try {
                 return api.listNamespaceCall(
@@ -52,7 +52,7 @@ public static void main(String[] args) throws IOException {
                     null,
                     param.getLimit(),
                     null,
-                    null,
+                    1,
                     null,
                     null,
                     null);
@@ -61,10 +61,10 @@ public static void main(String[] args) throws IOException {
               }
             },
             client,
-            3,
+            10,
             V1NamespaceList.class);
     while (pager.hasNext()) {
-      V1NamespaceList list = pager.next();
+      V1NamespaceList list = (V1NamespaceList) pager.next();
       List<V1Namespace> items = list.getItems();
       System.out.println("count:" + items.size());
       for (V1Namespace namespace : items) {

util/src/main/java/io/kubernetes/client/pager/Pager.java

@@ -1,18 +1,29 @@
+/*
+Copyright 2019 The Kubernetes Authors.
+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.
+ */
 package io.kubernetes.client.pager;
 
 import com.squareup.okhttp.Call;
 import io.kubernetes.client.ApiClient;
 import io.kubernetes.client.ApiException;
 import io.kubernetes.client.models.V1ListMeta;
-import io.kubernetes.client.util.PagerParams;
 import io.kubernetes.client.util.Reflect;
 import io.kubernetes.client.util.exception.ObjectMetaReflectException;
 import java.io.IOException;
 import java.lang.reflect.Type;
 import java.util.function.Function;
 
-public class Pager {
-  private String _continue;
+public class Pager<ApiType, ApiListType> {
+  private String continueToken;
   private Integer limit;
   private ApiClient client;
   private Call call;
@@ -22,10 +33,11 @@ public class Pager {
   /**
    * Pagination in kubernetes list call depends on continue and limit variable
    *
-   * @param listFunc
-   * @param client
-   * @param limit
-   * @param listType
+   * @param listFunc lambda of type: (PagerParams p)->{return
+   *     list<*>[namespace[s|d]]*<*>Call(...p.getContinue(),...p.getLimit()...);}
+   * @param client instance of {@link ApiClient}
+   * @param limit size of list to be fetched
+   * @param listType Type of list to be fetched
    */
   public Pager(
       Function<PagerParams, Call> listFunc, ApiClient client, Integer limit, Type listType) {
@@ -41,7 +53,7 @@ public Pager(
    * @return
    */
   public Boolean hasNext() {
-    if (_continue == null && call != null) {
+    if (continueToken == null && call != null) {
       return Boolean.FALSE;
     }
     return Boolean.TRUE;
@@ -52,56 +64,43 @@ public Boolean hasNext() {
    *
    * @return Object
    */
-  public <T> T next() {
+  public <ApiType> ApiListType next() {
     return next(null);
   }
 
   /**
-   * returns next chunk of List. size of list depends on limit set in constructor or nextLimit.
+   * returns next chunk of list. size of list depends on limit set in constructor or nextLimit.
    *
    * @param nextLimit
    * @return
    */
-  public <T> T next(Integer nextLimit) {
+  public <ApiType> ApiListType next(Integer nextLimit) {
     try {
       call = getNextCall(nextLimit);
-      return executeRequest(client, call, listType);
+      return executeRequest(call);
     } catch (Exception e) {
+      if (e instanceof ApiException) {
+        throw new RuntimeException(((ApiException) e).getResponseBody());
+      }
       throw new RuntimeException(e);
     }
   }
 
-  /**
-   * returns next list call by setting continue variable and limit
-   *
-   * @param nextLimit
-   * @return Object
-   */
+  /** returns next list call by setting continue variable and limit */
   private Call getNextCall(Integer nextLimit) {
-    PagerParams params = new PagerParams();
-    if (_continue != null) {
-      params.setContinue(_continue);
+    PagerParams params = new PagerParams((nextLimit != null) ? nextLimit : limit);
+    if (continueToken != null) {
+      params.setContinue(continueToken);
     }
-    params.setLimit((nextLimit != null) ? nextLimit : limit);
     return listFunc.apply(params);
   }
 
-  /**
-   * executes the list call and sets the continue variable for next list call
-   *
-   * @param client
-   * @param call
-   * @param listType
-   * @return
-   * @throws IOException
-   * @throws ApiException
-   * @throws ObjectMetaReflectException
-   */
-  private <T> T executeRequest(ApiClient client, Call call, Type listType)
+  /** executes the list call and sets the continue variable for next list call */
+  private <ApiType> ApiListType executeRequest(Call call)
       throws IOException, ApiException, ObjectMetaReflectException {
-    T data = client.handleResponse(call.execute(), listType);
+    ApiListType data = client.handleResponse(call.execute(), listType);
     V1ListMeta listMetaData = Reflect.listMetadata(data);
-    _continue = listMetaData.getContinue();
+    continueToken = listMetaData.getContinue();
     return data;
   }
 }

util/src/main/java/io/kubernetes/client/pager/PagerParams.java

@@ -0,0 +1,40 @@
+/*
+Copyright 2019 The Kubernetes Authors.
+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.
+ */
+package io.kubernetes.client.pager;
+
+public class PagerParams {
+
+  private Integer limit;
+  private String continueToken;
+
+  public PagerParams(Integer limit) {
+    this.limit = limit;
+  }
+
+  public PagerParams(Integer limit, String continueToken) {
+    this.limit = limit;
+    this.continueToken = continueToken;
+  }
+
+  public Integer getLimit() {
+    return limit;
+  }
+
+  public String getContinue() {
+    return continueToken;
+  }
+
+  public void setContinue(String continueToken) {
+    this.continueToken = continueToken;
+  }
+}