software.amazon.awssdk.enhanced.dynamodb.model.QueryEnhancedRequest 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.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import software.amazon.awssdk.annotations.SdkPublicApi;
import software.amazon.awssdk.enhanced.dynamodb.DynamoDbAsyncIndex;
import software.amazon.awssdk.enhanced.dynamodb.DynamoDbTable;
import software.amazon.awssdk.enhanced.dynamodb.Expression;
import software.amazon.awssdk.services.dynamodb.model.AttributeValue;
/**
* Defines parameters used to when querying a DynamoDb table or index using the query() operation (such as
* {@link DynamoDbTable#query(QueryEnhancedRequest)} or {@link DynamoDbAsyncIndex#query(QueryEnhancedRequest)}).
*
* A valid request object must contain a {@link QueryConditional} condition specifying how DynamoDb
* should match items in the table.
*
* All other parameters are optional.
*/
@SdkPublicApi
public final class QueryEnhancedRequest {
private final QueryConditional queryConditional;
private final Map exclusiveStartKey;
private final Boolean scanIndexForward;
private final Integer limit;
private final Boolean consistentRead;
private final Expression filterExpression;
private final List attributesToProject;
private QueryEnhancedRequest(Builder builder) {
this.queryConditional = builder.queryConditional;
this.exclusiveStartKey = builder.exclusiveStartKey;
this.scanIndexForward = builder.scanIndexForward;
this.limit = builder.limit;
this.consistentRead = builder.consistentRead;
this.filterExpression = builder.filterExpression;
this.attributesToProject = builder.attributesToProject != null
? Collections.unmodifiableList(builder.attributesToProject)
: null;
}
/**
* Creates a newly initialized builder for a request object.
*/
public static Builder builder() {
return new Builder();
}
/**
* Returns a builder initialized with all existing values on the request object.
*/
public Builder toBuilder() {
return builder().queryConditional(queryConditional)
.exclusiveStartKey(exclusiveStartKey)
.scanIndexForward(scanIndexForward)
.limit(limit)
.consistentRead(consistentRead)
.filterExpression(filterExpression)
.attributesToProject(attributesToProject);
}
/**
* Returns the matching condition of the query.
*/
public QueryConditional queryConditional() {
return queryConditional;
}
/**
* Returns the value of the exclusive start key set on this request object, or null if it doesn't exist.
*/
public Map exclusiveStartKey() {
return exclusiveStartKey;
}
/**
* Returns the value of scan index forward, meaning an ascending result sort order, or true if it
* has not been set.
*/
public Boolean scanIndexForward() {
return scanIndexForward;
}
/**
* Returns the value of limit set on this request object, or null if it doesn't exist.
*/
public Integer limit() {
return limit;
}
/**
* Returns the value of consistent read, or false if it has not been set.
*/
public Boolean consistentRead() {
return consistentRead;
}
/**
* Returns the return result filter {@link Expression} set on this request object, or null if it doesn't exist.
*/
public Expression filterExpression() {
return filterExpression;
}
/**
* Returns the list of projected attributes on this request object, or an null if no projection is specified.
*/
public List attributesToProject() {
return attributesToProject;
}
@Override
public boolean equals(Object o) {
if (this == o) {
return true;
}
if (o == null || getClass() != o.getClass()) {
return false;
}
QueryEnhancedRequest query = (QueryEnhancedRequest) o;
if (queryConditional != null ? ! queryConditional.equals(query.queryConditional) :
query.queryConditional != null) {
return false;
}
if (exclusiveStartKey != null ? ! exclusiveStartKey.equals(query.exclusiveStartKey) :
query.exclusiveStartKey != null) {
return false;
}
if (scanIndexForward != null ? ! scanIndexForward.equals(query.scanIndexForward) :
query.scanIndexForward != null) {
return false;
}
if (limit != null ? ! limit.equals(query.limit) : query.limit != null) {
return false;
}
if (consistentRead != null ? ! consistentRead.equals(query.consistentRead) : query.consistentRead != null) {
return false;
}
if (attributesToProject != null
? ! attributesToProject.equals(query.attributesToProject)
: query.attributesToProject != null
) {
return false;
}
return filterExpression != null ? filterExpression.equals(query.filterExpression) : query.filterExpression == null;
}
@Override
public int hashCode() {
int result = queryConditional != null ? queryConditional.hashCode() : 0;
result = 31 * result + (exclusiveStartKey != null ? exclusiveStartKey.hashCode() : 0);
result = 31 * result + (scanIndexForward != null ? scanIndexForward.hashCode() : 0);
result = 31 * result + (limit != null ? limit.hashCode() : 0);
result = 31 * result + (consistentRead != null ? consistentRead.hashCode() : 0);
result = 31 * result + (filterExpression != null ? filterExpression.hashCode() : 0);
result = 31 * result + (attributesToProject != null ? attributesToProject.hashCode() : 0);
return result;
}
/**
* A builder that is used to create a request with the desired parameters.
*
* A valid builder must set the {@link #queryConditional} parameter. Other parameters are optional.
*/
public static final class Builder {
private QueryConditional queryConditional;
private Map exclusiveStartKey;
private Boolean scanIndexForward;
private Integer limit;
private Boolean consistentRead;
private Expression filterExpression;
private List attributesToProject;
private Builder() {
}
/**
* Determines the matching conditions for this query request. See {@link QueryConditional} for examples
* and constraints. Required.
*
* @param queryConditional the query conditions
* @return a builder of this type
*/
public Builder queryConditional(QueryConditional queryConditional) {
this.queryConditional = queryConditional;
return this;
}
/**
* Results are sorted by sort key in ascending order if {@link #scanIndexForward} is true. If its false, the
* order is descending. The default value is true.
*
* @param scanIndexForward the sort order
* @return a builder of this type
*/
public Builder scanIndexForward(Boolean scanIndexForward) {
this.scanIndexForward = scanIndexForward;
return this;
}
/**
* The primary key of the first item that this operation will evaluate. By default, the operation will evaluate
* the whole dataset. If used, normally this parameter is populated with the value that was returned for
* {@link Page#lastEvaluatedKey()} in the previous operation.
*
* @param exclusiveStartKey the primary key value where DynamoDb should start to evaluate items
* @return a builder of this type
*/
public Builder exclusiveStartKey(Map exclusiveStartKey) {
this.exclusiveStartKey = exclusiveStartKey != null ? new HashMap<>(exclusiveStartKey) : null;
return this;
}
/**
* Sets a limit on how many items to evaluate in the query. If not set, the operation uses
* the maximum values allowed.
*
* Note:The limit does not refer to the number of items to return, but how many items
* the database should evaluate while executing the query. Use limit together with {@link Page#lastEvaluatedKey()}
* and {@link #exclusiveStartKey} in subsequent query calls to evaluate limit items per call.
*
* @param limit the maximum number of items to evalute
* @return a builder of this type
*/
public Builder limit(Integer limit) {
this.limit = limit;
return this;
}
/**
* Determines the read consistency model: If set to true, the operation uses strongly consistent reads; otherwise,
* the operation uses eventually consistent reads.
*
* By default, the value of this property is set to false.
*
* @param consistentRead sets consistency model of the operation to use strong consistency
* @return a builder of this type
*/
public Builder consistentRead(Boolean consistentRead) {
this.consistentRead = consistentRead;
return this;
}
/**
* Refines the query results by applying the filter expression on the results returned
* from the query and discards items that do not match. See {@link Expression} for examples
* and constraints.
*
* Note: Using the filter expression does not reduce the cost of the query, since it is applied
* after the database has found matching items.
*
* @param filterExpression an expression that filters results of evaluating the query
* @return a builder of this type
*/
public Builder filterExpression(Expression filterExpression) {
this.filterExpression = filterExpression;
return this;
}
/**
*
* Sets a collection of the attribute names to be retrieved from the database. These attributes can include
* scalars, sets, or elements of a JSON document.
*
*
* If no attribute names are specified, then all attributes will be returned. If any of the requested attributes
* are not found, they will not appear in the result.
*
*
* For more information, see Accessing Item Attributes in the Amazon DynamoDB Developer Guide.
*
* @param attributesToProject
* A collection of the attributes names to be retrieved from the database.
* @return Returns a reference to this object so that method calls can be chained together.
*/
public Builder attributesToProject(Collection attributesToProject) {
this.attributesToProject = attributesToProject != null ? new ArrayList<>(attributesToProject) : null;
return this;
}
/**
*
* Sets one or more attribute names to be retrieved from the database. These attributes can include
* scalars, sets, or elements of a JSON document.
*
*
* If no attribute names are specified, then all attributes will be returned. If any of the requested attributes
* are not found, they will not appear in the result.
*
*
* For more information, see Accessing Item Attributes in the Amazon DynamoDB Developer Guide.
*
* @param attributesToProject
* One or more attributes names to be retrieved from the database.
* @return Returns a reference to this object so that method calls can be chained together.
*/
public Builder attributesToProject(String... attributesToProject) {
return attributesToProject(Arrays.asList(attributesToProject));
}
/**
*
* Adds a single attribute name to be retrieved from the database. This attribute can include
* scalars, sets, or elements of a JSON document.
*
*
* For more information, see Accessing Item Attributes in the Amazon DynamoDB Developer Guide.
*
* @param attributeToProject
* An additional single attribute name to be retrieved from the database.
* @return Returns a reference to this object so that method calls can be chained together.
*/
public Builder addAttributeToProject(String attributeToProject) {
if (attributesToProject == null) {
attributesToProject = new ArrayList<>();
}
attributesToProject.add(attributeToProject);
return this;
}
public QueryEnhancedRequest build() {
return new QueryEnhancedRequest(this);
}
}
}