com.jcabi.dynamo.Item Maven / Gradle / Ivy
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package com.jcabi.dynamo;
import com.amazonaws.services.dynamodbv2.model.AttributeValue;
import com.amazonaws.services.dynamodbv2.model.AttributeValueUpdate;
import com.jcabi.aspects.Immutable;
import java.io.IOException;
import java.util.Map;
/**
* Immutable Amazon DynamoDB item.
*
* The class is immutable, which means that every call to
* {@link #put(String,AttributeValueUpdate)} or {@link #put(Map)} changes
* data in Amazon, but doesn't change the object. The object will contain
* dirty data right after PUT operation, and should not be used any more.
*
* @since 0.1
*/
@Immutable
public interface Item {
/**
* Get one attribute, fetching directly from AWS (runtime exception if
* the attribute is absent, use {@link #has(String)} first).
* @param name Attribute name
* @return Value
* @throws IOException In case of DynamoDB failure
*/
AttributeValue get(String name) throws IOException;
/**
* Does this attribute exist?
* @param name Attribute name
* @return TRUE if it exists
* @throws IOException In case of DynamoDB failure
*/
boolean has(String name)
throws IOException;
/**
* Change one attribute, immediately saving it to AWS (all other attributes
* will be set to NULL, except primary keys).
*
*
Data in memory will become out of sync right after a successful
* execution of the method.
*
* @param name Attribute name
* @param value Value to save
* @return Values saved
* @throws IOException In case of DynamoDB failure
* @since 0.12
*/
Map put(String name, AttributeValueUpdate value)
throws IOException;
/**
* Change all attributes in one call.
*
* Data in memory will become out of sync right after a successful
* execution of the method.
*
*
It is recommended to use {@link AttributeUpdates} supplementary class,
* instead of a raw {@link Map}.
*
* @param attrs Attributes
* @return Values saved
* @throws IOException In case of DynamoDB failure
* @since 0.12
*/
Map put(Map attrs)
throws IOException;
/**
* Get back to the frame it is from.
* @return Frame
*/
Frame frame();
}