com.netflix.spinnaker.clouddriver.google.provider.agent.util.PaginatedRequest Maven / Gradle / Ivy

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/*
 * Copyright 2018 Google, Inc.
 *
 * 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 com.netflix.spinnaker.clouddriver.google.provider.agent.util;

import com.google.api.client.googleapis.batch.json.JsonBatchCallback;
import com.google.api.services.compute.ComputeRequest;
import com.netflix.spinnaker.clouddriver.google.batch.GoogleBatchRequest;
import com.netflix.spinnaker.clouddriver.google.provider.agent.AbstractGoogleCachingAgent;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.function.Function;

public abstract class PaginatedRequest {
  private final AbstractGoogleCachingAgent cachingAgent;

  public PaginatedRequest(AbstractGoogleCachingAgent cachingAgent) {
    this.cachingAgent = cachingAgent;
  }

  public void queue(
      GoogleBatchRequest googleBatchRequest,
      JsonBatchCallback callback,
      String instrumentationContext)
      throws IOException {
    PaginatedCallback paginatedCallback =
        new PaginatedCallback(callback) {
          @Override
          protected void requestNextBatch(T t) throws IOException {
            String nextPageToken = getNextPageToken(t);
            GoogleBatchRequest batch = cachingAgent.buildGoogleBatchRequest();
            if (nextPageToken != null) {
              batch.queue(request(nextPageToken), this);
            }
            cachingAgent.executeIfRequestsAreQueued(batch, instrumentationContext);
          }
        };
    googleBatchRequest.queue(request(null), paginatedCallback);
  }

  public  List timeExecute(Function> itemExtractor, String api, String... tags)
      throws IOException {
    String pageToken = null;
    List resultList = new ArrayList<>();
    do {
      T results = cachingAgent.timeExecute(request(pageToken), api, tags);
      List newItems = itemExtractor.apply(results);
      if (newItems != null) {
        resultList.addAll(newItems);
      }
      pageToken = getNextPageToken(results);
    } while (pageToken != null);
    return resultList;
  }

  protected abstract String getNextPageToken(T t);

  protected abstract ComputeRequest request(String pageToken);
}