software.amazon.awssdk.services.databasemigration.paginators.DescribeEventSubscriptionsPaginator Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of dms Show documentation
The AWS Java SDK for AWS Database Migration Service module holds the client classes that are used for communicating with AWS Database Migration Service.
There is a newer version: 2.0.0-preview-11
Show newest version
/*
 * Copyright 2012-2017 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.Iterator;
import javax.annotation.Generated;
import software.amazon.awssdk.core.pagination.NextPageFetcher;
import software.amazon.awssdk.core.pagination.PaginatedResponsesIterator;
import software.amazon.awssdk.core.pagination.SdkIterable;
import software.amazon.awssdk.services.databasemigration.DatabaseMigrationClient;
import software.amazon.awssdk.services.databasemigration.model.DescribeEventSubscriptionsRequest;
import software.amazon.awssdk.services.databasemigration.model.DescribeEventSubscriptionsResponse;

/**
 * 
 * Represents the output for the
 * {@link software.amazon.awssdk.services.databasemigration.DatabaseMigrationClient#describeEventSubscriptionsIterable(software.amazon.awssdk.services.databasemigration.model.DescribeEventSubscriptionsRequest)}
 * operation which is a paginated operation. This class is an iterable of
 * {@link software.amazon.awssdk.services.databasemigration.model.DescribeEventSubscriptionsResponse} 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.DescribeEventSubscriptionsPaginator responses = client.describeEventSubscriptionsIterable(request);
 * responses.stream().forEach(....);
 * }
 * 
 *
 * 2) Using For loop
 * 
 *  * {
 *     @code
 *     software.amazon.awssdk.services.databasemigration.paginators.DescribeEventSubscriptionsPaginator responses = client
 *             .describeEventSubscriptionsIterable(request);
 *     for (software.amazon.awssdk.services.databasemigration.model.DescribeEventSubscriptionsResponse response : responses) {
 *         // do something;
 *     }
 * }
 * 
 *
 * 3) Use iterator directly
 * 
 *  * {@code
 * software.amazon.awssdk.services.databasemigration.paginators.DescribeEventSubscriptionsPaginator responses = client.describeEventSubscriptionsIterable(request);
 * responses.iterator().forEachRemaining(....);
 * }
 * 
 * 
 * Note: If you prefer to have control on service calls, use the
 * {@link #describeEventSubscriptions(software.amazon.awssdk.services.databasemigration.model.DescribeEventSubscriptionsRequest)}
 * operation.
 * 
 */
@Generated("software.amazon.awssdk:codegen")
public final class DescribeEventSubscriptionsPaginator implements SdkIterable {
    private final DatabaseMigrationClient client;

    private final DescribeEventSubscriptionsRequest firstRequest;

    private final NextPageFetcher nextPageFetcher;

    public DescribeEventSubscriptionsPaginator(final DatabaseMigrationClient client,
            final DescribeEventSubscriptionsRequest firstRequest) {
        this.client = client;
        this.firstRequest = firstRequest;
        this.nextPageFetcher = new DescribeEventSubscriptionsResponseFetcher();
    }

    @Override
    public Iterator iterator() {
        return new PaginatedResponsesIterator(nextPageFetcher);
    }

    private class DescribeEventSubscriptionsResponseFetcher implements NextPageFetcher {
        @Override
        public boolean hasNextPage(DescribeEventSubscriptionsResponse previousPage) {
            return previousPage.marker() != null;
        }

        @Override
        public DescribeEventSubscriptionsResponse nextPage(DescribeEventSubscriptionsResponse previousPage) {
            if (previousPage == null) {
                return client.describeEventSubscriptions(firstRequest);
            }
            return client.describeEventSubscriptions(firstRequest.toBuilder().marker(previousPage.marker()).build());
        }
    }
}