software.amazon.awssdk.enhanced.dynamodb.model.PageIterable 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.enhanced.dynamodb.model;

import software.amazon.awssdk.annotations.SdkPublicApi;
import software.amazon.awssdk.annotations.ThreadSafe;
import software.amazon.awssdk.core.pagination.sync.PaginatedItemsIterable;
import software.amazon.awssdk.core.pagination.sync.SdkIterable;

/**
 * Page iterable represents the result from paginated operations such as scan and query.
 *
 * 
 * The result can be accessed either through iterable {@link Page}s or flattened items across all  pages via
 * {@link #items()}
 *
 * 

 * Example:
 * 

 * 1) Iterating through pages
 *
 * 
 * {@code
 * PageIterable results = table.scan();
 * results.stream().forEach(p -> p.items().forEach(item -> System.out.println(item)))
 * }
 * 
 *
 * 2) Iterating through items
 *
 *  * {@code
 * PageIterable results = table.scan();
 * results.items().stream().forEach(item -> System.out.println(item));
 * }
 * 
 * @param  The modelled type of the object in a page.
 */
@SdkPublicApi
@ThreadSafe
public interface PageIterable extends SdkIterable> {

    static  PageIterable create(SdkIterable> pageIterable) {
        return pageIterable::iterator;
    }

    /**
     * Returns an iterable to iterate through the paginated {@link Page#items()} across all response pages.
     *
     * 
     * This method is useful if you are interested in iterating over the items in the response pages
     * instead of the top level pages.
     */
    default SdkIterable items() {
        return PaginatedItemsIterable., T>builder()
            .pagesIterable(this)
            .itemIteratorFunction(page -> page.items().iterator())
            .build();
    }
}