software.amazon.awssdk.services.redshift.paginators.DescribeClustersIterable Maven / Gradle / Ivy
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/*
* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License"). You may not use this file except in compliance with
* the License. A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file 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 software.amazon.awssdk.services.redshift.paginators;
import java.util.Collections;
import java.util.Iterator;
import java.util.function.Function;
import software.amazon.awssdk.annotations.Generated;
import software.amazon.awssdk.core.pagination.sync.PaginatedItemsIterable;
import software.amazon.awssdk.core.pagination.sync.PaginatedResponsesIterator;
import software.amazon.awssdk.core.pagination.sync.SdkIterable;
import software.amazon.awssdk.core.pagination.sync.SyncPageFetcher;
import software.amazon.awssdk.core.util.PaginatorUtils;
import software.amazon.awssdk.services.redshift.RedshiftClient;
import software.amazon.awssdk.services.redshift.internal.UserAgentUtils;
import software.amazon.awssdk.services.redshift.model.Cluster;
import software.amazon.awssdk.services.redshift.model.DescribeClustersRequest;
import software.amazon.awssdk.services.redshift.model.DescribeClustersResponse;
/**
*
* Represents the output for the
* {@link software.amazon.awssdk.services.redshift.RedshiftClient#describeClustersPaginator(software.amazon.awssdk.services.redshift.model.DescribeClustersRequest)}
* operation which is a paginated operation. This class is an iterable of
* {@link software.amazon.awssdk.services.redshift.model.DescribeClustersResponse} that can be used to iterate through
* all the response pages of the operation.
*
*
* When the operation is called, an instance of this class is returned. At this point, no service calls are made yet and
* so there is no guarantee that the request is valid. As you iterate through the iterable, SDK will start lazily
* loading response pages by making service calls until there are no pages left or your iteration stops. If there are
* errors in your request, you will see the failures only after you start iterating through the iterable.
*
*
*
* The following are few ways to iterate through the response pages:
*
* 1) Using a Stream
*
*
* {@code
* software.amazon.awssdk.services.redshift.paginators.DescribeClustersIterable responses = client.describeClustersPaginator(request);
* responses.stream().forEach(....);
* }
*
*
* 2) Using For loop
*
*
* {
* @code
* software.amazon.awssdk.services.redshift.paginators.DescribeClustersIterable responses = client
* .describeClustersPaginator(request);
* for (software.amazon.awssdk.services.redshift.model.DescribeClustersResponse response : responses) {
* // do something;
* }
* }
*
*
* 3) Use iterator directly
*
*
* {@code
* software.amazon.awssdk.services.redshift.paginators.DescribeClustersIterable responses = client.describeClustersPaginator(request);
* responses.iterator().forEachRemaining(....);
* }
*
*
* Please notice that the configuration of MaxRecords won't limit the number of results you get with the paginator.
* It only limits the number of results in each page.
*
*
* Note: If you prefer to have control on service calls, use the
* {@link #describeClusters(software.amazon.awssdk.services.redshift.model.DescribeClustersRequest)} operation.
*
*/
@Generated("software.amazon.awssdk:codegen")
public class DescribeClustersIterable implements SdkIterable {
private final RedshiftClient client;
private final DescribeClustersRequest firstRequest;
private final SyncPageFetcher nextPageFetcher;
public DescribeClustersIterable(RedshiftClient client, DescribeClustersRequest firstRequest) {
this.client = client;
this.firstRequest = UserAgentUtils.applyPaginatorUserAgent(firstRequest);
this.nextPageFetcher = new DescribeClustersResponseFetcher();
}
@Override
public Iterator iterator() {
return PaginatedResponsesIterator.builder().nextPageFetcher(nextPageFetcher).build();
}
/**
* Returns an iterable to iterate through the paginated {@link DescribeClustersResponse#clusters()} member. The
* returned iterable is used to iterate through the results across all response pages and not a single page.
*
* This method is useful if you are interested in iterating over the paginated member in the response pages instead
* of the top level pages. Similar to iteration over pages, this method internally makes service calls to get the
* next list of results until the iteration stops or there are no more results.
*/
public final SdkIterable clusters() {
Function> getIterator = response -> {
if (response != null && response.clusters() != null) {
return response.clusters().iterator();
}
return Collections.emptyIterator();
};
return PaginatedItemsIterable. builder().pagesIterable(this)
.itemIteratorFunction(getIterator).build();
}
private class DescribeClustersResponseFetcher implements SyncPageFetcher {
@Override
public boolean hasNextPage(DescribeClustersResponse previousPage) {
return PaginatorUtils.isOutputTokenAvailable(previousPage.marker());
}
@Override
public DescribeClustersResponse nextPage(DescribeClustersResponse previousPage) {
if (previousPage == null) {
return client.describeClusters(firstRequest);
}
return client.describeClusters(firstRequest.toBuilder().marker(previousPage.marker()).build());
}
}
}