software.amazon.awssdk.enhanced.dynamodb.model.ConditionCheck 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.function.Consumer;
import software.amazon.awssdk.annotations.SdkPublicApi;
import software.amazon.awssdk.enhanced.dynamodb.DynamoDbEnhancedClient;
import software.amazon.awssdk.enhanced.dynamodb.DynamoDbEnhancedClientExtension;
import software.amazon.awssdk.enhanced.dynamodb.Expression;
import software.amazon.awssdk.enhanced.dynamodb.Key;
import software.amazon.awssdk.enhanced.dynamodb.OperationContext;
import software.amazon.awssdk.enhanced.dynamodb.TableSchema;
import software.amazon.awssdk.enhanced.dynamodb.internal.operations.TransactableWriteOperation;
import software.amazon.awssdk.services.dynamodb.model.TransactWriteItem;
/**
* Use ConditionCheck as a part of the composite operation transactGetItems (for example
* {@link DynamoDbEnhancedClient#transactGetItems(TransactGetItemsEnhancedRequest)}) to determine
* if the other actions that are part of the same transaction should take effect.
*
* A valid ConditionCheck object should contain a reference to the primary key of the table that finds items with a matching key,
* together with a condition (of type {@link Expression}) to evaluate the primary key.
*
* @param The type of the modelled object.
*/
@SdkPublicApi
public final class ConditionCheck implements TransactableWriteOperation {
private final Key key;
private final Expression conditionExpression;
private ConditionCheck(Key key, Expression conditionExpression) {
this.key = key;
this.conditionExpression = conditionExpression;
}
/**
* Creates a newly initialized builder for this object.
*/
public static Builder builder() {
return new Builder();
}
/**
* Returns a builder initialized with all existing values on the object.
*/
public Builder toBuilder() {
return new Builder().key(key).conditionExpression(conditionExpression);
}
@Override
public TransactWriteItem generateTransactWriteItem(TableSchema tableSchema,
OperationContext operationContext,
DynamoDbEnhancedClientExtension dynamoDbEnhancedClientExtension) {
software.amazon.awssdk.services.dynamodb.model.ConditionCheck conditionCheck =
software.amazon.awssdk.services.dynamodb.model.ConditionCheck
.builder()
.tableName(operationContext.tableName())
.key(key.keyMap(tableSchema, operationContext.indexName()))
.conditionExpression(conditionExpression.expression())
.expressionAttributeNames(conditionExpression.expressionNames())
.expressionAttributeValues(conditionExpression.expressionValues())
.build();
return TransactWriteItem.builder()
.conditionCheck(conditionCheck)
.build();
}
/**
* Returns the primary {@link Key} that the condition is valid for, or null if it doesn't exist.
*/
public Key key() {
return key;
}
/**
* Returns the condition {@link Expression} set on this object, or null if it doesn't exist.
*/
public Expression conditionExpression() {
return conditionExpression;
}
@Override
public boolean equals(Object o) {
if (this == o) {
return true;
}
if (o == null || getClass() != o.getClass()) {
return false;
}
ConditionCheck that = (ConditionCheck) o;
if (key != null ? ! key.equals(that.key) : that.key != null) {
return false;
}
return conditionExpression != null ? conditionExpression.equals(that.conditionExpression) :
that.conditionExpression == null;
}
@Override
public int hashCode() {
int result = key != null ? key.hashCode() : 0;
result = 31 * result + (conditionExpression != null ? conditionExpression.hashCode() : 0);
return result;
}
/**
* A builder that is used to create a condition check with the desired parameters.
*
* A valid builder must define both a {@link Key} and an {@link Expression}.
*/
public static final class Builder {
private Key key;
private Expression conditionExpression;
private Builder() {
}
/**
* Sets the primary {@link Key} that will be used together with the condition expression.
*
* @param key the primary key to use in the operation.
* @return a builder of this type
*/
public Builder key(Key key) {
this.key = key;
return this;
}
/**
* Sets the primary {@link Key} that will be used together with the condition expression
* on the builder by accepting a consumer of {@link Key.Builder}.
*
* @param keyConsumer a {@link Consumer} of {@link Key}
* @return a builder of this type
*/
public Builder key(Consumer keyConsumer) {
Key.Builder builder = Key.builder();
keyConsumer.accept(builder);
return key(builder.build());
}
/**
* Defines a logical expression on the attributes of table items that match the supplied primary key value(s).
* If the expression evaluates to true, the transaction operation succeeds. If the expression evaluates to false,
* the transaction will not succeed.
*
* See {@link Expression} for condition syntax and examples.
*
* @param conditionExpression a condition written as an {@link Expression}
* @return a builder of this type
*/
public Builder conditionExpression(Expression conditionExpression) {
this.conditionExpression = conditionExpression;
return this;
}
public ConditionCheck build() {
return new ConditionCheck<>(key, conditionExpression);
}
}
}