software.amazon.awssdk.enhanced.dynamodb.model.Page Maven / Gradle / Ivy
/*
* 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 java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import software.amazon.awssdk.annotations.SdkPublicApi;
import software.amazon.awssdk.annotations.ThreadSafe;
import software.amazon.awssdk.services.dynamodb.model.AttributeValue;
import software.amazon.awssdk.services.dynamodb.model.ConsumedCapacity;
import software.amazon.awssdk.utils.ToString;
/**
* An immutable object that holds a page of queried or scanned results from DynamoDb.
*
* Contains a reference to the last evaluated key for the current page; see {@link #lastEvaluatedKey()} for more information.
* @param The modelled type of the object that has been read.
*/
@SdkPublicApi
@ThreadSafe
public final class Page {
private final List items;
private final Map lastEvaluatedKey;
private final Integer count;
private final Integer scannedCount;
private final ConsumedCapacity consumedCapacity;
private Page(List items, Map lastEvaluatedKey) {
this.items = items;
this.lastEvaluatedKey = lastEvaluatedKey;
this.count = null;
this.scannedCount = null;
this.consumedCapacity = null;
}
private Page(Builder builder) {
this.items = builder.items;
this.lastEvaluatedKey = builder.lastEvaluatedKey;
this.count = builder.count;
this.scannedCount = builder.scannedCount;
this.consumedCapacity = builder.consumedCapacity;
}
/**
* Static constructor for this object. Deprecated in favor of using the builder() pattern to construct this object.
*
* @param items A list of items to store for the page.
* @param lastEvaluatedKey A 'lastEvaluatedKey' to store for the page.
* @param The modelled type of the object that has been read.
* @return A newly constructed {@link Page} object.
*/
@Deprecated
public static Page create(List items, Map lastEvaluatedKey) {
return new Page<>(items, lastEvaluatedKey);
}
/**
* Static constructor for this object that sets a null 'lastEvaluatedKey' which indicates this is the final page
* of results. Deprecated in favor of using the builder() pattern to construct this object.
* @param items A list of items to store for the page.
* @param The modelled type of the object that has been read.
* @return A newly constructed {@link Page} object.
*/
@Deprecated
public static Page create(List items) {
return new Page<>(items, null);
}
/**
* Returns a page of mapped objects that represent records from a database query or scan.
* @return A list of mapped objects.
*/
public List items() {
return items;
}
/**
* Returns the 'lastEvaluatedKey' that DynamoDb returned from the last page query or scan. This key can be used
* to continue the query or scan if passed into a request.
* @return The 'lastEvaluatedKey' from the last query or scan operation or null if the no more pages are available.
*/
public Map lastEvaluatedKey() {
return lastEvaluatedKey;
}
/**
* The count of the returned items from the last page query or scan, after any filters were applied.
*/
public Integer count() {
return count;
}
/**
* The scanned count of the returned items from the last page query or scan, before any filters were applied.
* This number will be equal or greater than the count.
*/
public Integer scannedCount() {
return scannedCount;
}
/**
* Returns the capacity units consumed by the last page query or scan. Will only be returned if it has been
* explicitly requested by the user when calling the operation.
*
* @return The 'consumedCapacity' from the last query or scan operation or null if it was not requested.
*/
public ConsumedCapacity consumedCapacity() {
return consumedCapacity;
}
@Override
public boolean equals(Object o) {
if (this == o) {
return true;
}
if (o == null || getClass() != o.getClass()) {
return false;
}
Page page = (Page) o;
if (items != null ? ! items.equals(page.items) : page.items != null) {
return false;
}
if (lastEvaluatedKey != null ? ! lastEvaluatedKey.equals(page.lastEvaluatedKey) : page.lastEvaluatedKey != null) {
return false;
}
if (consumedCapacity != null ? ! consumedCapacity.equals(page.consumedCapacity) : page.consumedCapacity != null) {
return false;
}
if (count != null ? ! count.equals(page.count) : page.count != null) {
return false;
}
return scannedCount != null ? scannedCount.equals(page.scannedCount) : page.scannedCount == null;
}
@Override
public int hashCode() {
int result = items != null ? items.hashCode() : 0;
result = 31 * result + (lastEvaluatedKey != null ? lastEvaluatedKey.hashCode() : 0);
result = 31 * result + (consumedCapacity != null ? consumedCapacity.hashCode() : 0);
result = 31 * result + (count != null ? count.hashCode() : 0);
result = 31 * result + (scannedCount != null ? scannedCount.hashCode() : 0);
return result;
}
@Override
public String toString() {
return ToString.builder("Page")
.add("lastEvaluatedKey", lastEvaluatedKey)
.add("items", items)
.build();
}
public static Builder builder(Class itemClass) {
return new Builder<>();
}
public static final class Builder {
private List items;
private Map lastEvaluatedKey;
private Integer count;
private Integer scannedCount;
private ConsumedCapacity consumedCapacity;
public Builder items(List items) {
this.items = new ArrayList<>(items);
return this;
}
public Builder lastEvaluatedKey(Map lastEvaluatedKey) {
this.lastEvaluatedKey = new HashMap<>(lastEvaluatedKey);
return this;
}
public Builder count(Integer count) {
this.count = count;
return this;
}
public Builder scannedCount(Integer scannedCount) {
this.scannedCount = scannedCount;
return this;
}
public Builder consumedCapacity(ConsumedCapacity consumedCapacity) {
this.consumedCapacity = consumedCapacity;
return this;
}
public Page build() {
return new Page(this);
}
}
}