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Merge pull request #527 from kondapally1989/master
Adding pagination utility
2 parents ab632a5 + 2749d5b commit d600430

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

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/*
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Copyright 2019 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package io.kubernetes.client.examples;
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import io.kubernetes.client.ApiClient;
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import io.kubernetes.client.Configuration;
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import io.kubernetes.client.apis.CoreV1Api;
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import io.kubernetes.client.models.V1Namespace;
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import io.kubernetes.client.models.V1NamespaceList;
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import io.kubernetes.client.pager.Pager;
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import io.kubernetes.client.pager.PagerParams;
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import io.kubernetes.client.util.Config;
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import java.io.IOException;
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import java.util.List;
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import java.util.concurrent.TimeUnit;
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/**
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* A simple example of how to use the Java API
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*
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* <p>Easiest way to run this: mvn exec:java
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* -Dexec.mainClass="io.kubernetes.client.examples.PagerExample"
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*
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* <p>From inside $REPO_DIR/examples
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*/
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public class PagerExample {
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public static void main(String[] args) throws IOException {
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ApiClient client = Config.defaultClient();
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client.getHttpClient().setReadTimeout(60, TimeUnit.SECONDS);
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Configuration.setDefaultApiClient(client);
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CoreV1Api api = new CoreV1Api();
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int i = 0;
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Pager pager =
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new Pager<V1Namespace, V1NamespaceList>(
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(PagerParams param) -> {
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try {
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return api.listNamespaceCall(
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null,
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null,
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param.getContinue(),
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null,
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null,
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param.getLimit(),
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null,
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1,
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null,
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null,
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null);
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} catch (Exception e) {
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throw new RuntimeException(e);
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}
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},
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client,
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10,
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V1NamespaceList.class);
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while (pager.hasNext()) {
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V1NamespaceList list = (V1NamespaceList) pager.next();
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List<V1Namespace> items = list.getItems();
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System.out.println("count:" + items.size());
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for (V1Namespace namespace : items) {
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System.out.println(namespace.getMetadata().getName());
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}
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System.out.println("------------------" + (++i));
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}
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}
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}

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

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/*
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Copyright 2019 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package io.kubernetes.client.pager;
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import com.squareup.okhttp.Call;
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import io.kubernetes.client.ApiClient;
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import io.kubernetes.client.ApiException;
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import io.kubernetes.client.models.V1ListMeta;
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import io.kubernetes.client.util.Reflect;
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import io.kubernetes.client.util.exception.ObjectMetaReflectException;
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import java.io.IOException;
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import java.lang.reflect.Type;
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import java.util.function.Function;
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public class Pager<ApiType, ApiListType> {
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private String continueToken;
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private Integer limit;
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private ApiClient client;
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private Call call;
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private Type listType;
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private Function<PagerParams, Call> listFunc;
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/**
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* Pagination in kubernetes list call depends on continue and limit variable
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*
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* @param listFunc lambda of type: (PagerParams p)->{return
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* list<*>[namespace[s|d]]*<*>Call(...p.getContinue(),...p.getLimit()...);}
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* @param client instance of {@link ApiClient}
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* @param limit size of list to be fetched
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* @param listType Type of list to be fetched
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*/
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public Pager(
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Function<PagerParams, Call> listFunc, ApiClient client, Integer limit, Type listType) {
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this.listFunc = listFunc;
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this.client = client;
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this.limit = limit;
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this.listType = listType;
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}
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/**
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* returns false if kubernetes server has exhausted List.
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*
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* @return
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*/
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public Boolean hasNext() {
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if (continueToken == null && call != null) {
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return Boolean.FALSE;
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}
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return Boolean.TRUE;
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}
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/**
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* returns next chunk of List. size of list depends on limit set in constructor.
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*
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* @return Object
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*/
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public <ApiType> ApiListType next() {
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return next(null);
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}
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/**
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* returns next chunk of list. size of list depends on limit set in constructor or nextLimit.
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*
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* @param nextLimit
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* @return
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*/
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public <ApiType> ApiListType next(Integer nextLimit) {
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try {
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call = getNextCall(nextLimit);
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return executeRequest(call);
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} catch (Exception e) {
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if (e instanceof ApiException) {
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throw new RuntimeException(((ApiException) e).getResponseBody());
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}
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throw new RuntimeException(e);
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}
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}
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/** returns next list call by setting continue variable and limit */
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private Call getNextCall(Integer nextLimit) {
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PagerParams params = new PagerParams((nextLimit != null) ? nextLimit : limit);
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if (continueToken != null) {
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params.setContinue(continueToken);
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}
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return listFunc.apply(params);
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}
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/** executes the list call and sets the continue variable for next list call */
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private <ApiType> ApiListType executeRequest(Call call)
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throws IOException, ApiException, ObjectMetaReflectException {
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ApiListType data = client.handleResponse(call.execute(), listType);
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V1ListMeta listMetaData = Reflect.listMetadata(data);
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continueToken = listMetaData.getContinue();
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return data;
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}
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}

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

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/*
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Copyright 2019 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package io.kubernetes.client.pager;
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public class PagerParams {
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private Integer limit;
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private String continueToken;
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public PagerParams(Integer limit) {
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this.limit = limit;
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}
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public PagerParams(Integer limit, String continueToken) {
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this.limit = limit;
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this.continueToken = continueToken;
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}
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public Integer getLimit() {
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return limit;
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}
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public String getContinue() {
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return continueToken;
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}
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public void setContinue(String continueToken) {
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this.continueToken = continueToken;
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}
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}

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