software.amazon.awssdk.services.databasemigration.paginators.DescribeReplicationInstancesIterable Maven / Gradle / Ivy
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/*
* Copyright 2013-2018 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.databasemigration.paginators;
import java.util.Collections;
import java.util.Iterator;
import software.amazon.awssdk.annotations.Generated;
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.SdkAutoConstructList;
import software.amazon.awssdk.core.util.SdkAutoConstructMap;
import software.amazon.awssdk.services.databasemigration.DatabaseMigrationClient;
import software.amazon.awssdk.services.databasemigration.model.DescribeReplicationInstancesRequest;
import software.amazon.awssdk.services.databasemigration.model.DescribeReplicationInstancesResponse;
/**
*
* Represents the output for the
* {@link software.amazon.awssdk.services.databasemigration.DatabaseMigrationClient#describeReplicationInstancesPaginator(software.amazon.awssdk.services.databasemigration.model.DescribeReplicationInstancesRequest)}
* operation which is a paginated operation. This class is an iterable of
* {@link software.amazon.awssdk.services.databasemigration.model.DescribeReplicationInstancesResponse} 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.databasemigration.paginators.DescribeReplicationInstancesIterable responses = client.describeReplicationInstancesPaginator(request);
* responses.stream().forEach(....);
* }
*
*
* 2) Using For loop
*
*
* {
* @code
* software.amazon.awssdk.services.databasemigration.paginators.DescribeReplicationInstancesIterable responses = client
* .describeReplicationInstancesPaginator(request);
* for (software.amazon.awssdk.services.databasemigration.model.DescribeReplicationInstancesResponse response : responses) {
* // do something;
* }
* }
*
*
* 3) Use iterator directly
*
*
* {@code
* software.amazon.awssdk.services.databasemigration.paginators.DescribeReplicationInstancesIterable responses = client.describeReplicationInstancesPaginator(request);
* responses.iterator().forEachRemaining(....);
* }
*
*
* Note: If you prefer to have control on service calls, use the
* {@link #describeReplicationInstances(software.amazon.awssdk.services.databasemigration.model.DescribeReplicationInstancesRequest)}
* operation.
*
*/
@Generated("software.amazon.awssdk:codegen")
public class DescribeReplicationInstancesIterable implements SdkIterable {
private final DatabaseMigrationClient client;
private final DescribeReplicationInstancesRequest firstRequest;
private final SyncPageFetcher nextPageFetcher;
public DescribeReplicationInstancesIterable(DatabaseMigrationClient client, DescribeReplicationInstancesRequest firstRequest) {
this.client = client;
this.firstRequest = firstRequest;
this.nextPageFetcher = new DescribeReplicationInstancesResponseFetcher();
}
@Override
public Iterator iterator() {
return PaginatedResponsesIterator.builder().nextPageFetcher(nextPageFetcher).build();
}
/**
*
* A helper method to resume the pages in case of unexpected failures. The method takes the last successful response
* page as input and returns an instance of {@link DescribeReplicationInstancesIterable} that can be used to
* retrieve the consecutive pages that follows the input page.
*
*/
private final DescribeReplicationInstancesIterable resume(DescribeReplicationInstancesResponse lastSuccessfulPage) {
if (nextPageFetcher.hasNextPage(lastSuccessfulPage)) {
return new DescribeReplicationInstancesIterable(client, firstRequest.toBuilder().marker(lastSuccessfulPage.marker())
.build());
}
return new DescribeReplicationInstancesIterable(client, firstRequest) {
@Override
public Iterator iterator() {
return Collections.emptyIterator();
}
};
}
private class DescribeReplicationInstancesResponseFetcher implements SyncPageFetcher {
@Override
public boolean hasNextPage(DescribeReplicationInstancesResponse previousPage) {
return previousPage.marker() != null && !SdkAutoConstructList.class.isInstance(previousPage.marker())
&& !SdkAutoConstructMap.class.isInstance(previousPage.marker());
}
@Override
public DescribeReplicationInstancesResponse nextPage(DescribeReplicationInstancesResponse previousPage) {
if (previousPage == null) {
return client.describeReplicationInstances(firstRequest);
}
return client.describeReplicationInstances(firstRequest.toBuilder().marker(previousPage.marker()).build());
}
}
}