Java Code Examples for com.amazonaws.services.dynamodbv2.model.GetItemResult#getItem()

public static void retrieveItem(String threadId, String replyDateTime) throws IOException {
    HashMap<String, AttributeValue> key = new HashMap<String, AttributeValue>();
    key.put("Id", new AttributeValue().withS(threadId));
    key.put("ReplyDateTime", new AttributeValue().withS(replyDateTime));

    GetItemRequest getReplyRequest = new GetItemRequest().withTableName(tableName).withKey(key)
        .withConsistentRead(true);

    GetItemResult getReplyResult = client.getItem(getReplyRequest);

    // Decompress the reply message and print
    Map<String, AttributeValue> reply = getReplyResult.getItem();
    String message = decompressString(reply.get("ExtendedMessage").getB());
    System.out.println("Reply message:\n" + " Id: " + reply.get("Id").getS() + "\n" + " ReplyDateTime: "
        + reply.get("ReplyDateTime").getS() + "\n" + " PostedBy: " + reply.get("PostedBy").getS() + "\n"
        + " Message: " + reply.get("Message").getS() + "\n" + " ExtendedMessage (decompressed): " + message);
}
 

/**
 * Retrieves the stored ETag, if one exists, from DynamoDB.
 *
 * @param dynamoDB
 *            DynamoDB client configured with a region and credentials
 * @param table
 *            The resource table name
 * @param resource
 *            The URL String of the resource
 * @return The ETag String of the last copy processed or null if the resource has never been processed
 */
public static String getStoredETag(final AmazonDynamoDB dynamoDB, final String table, final String resource) {
    String oldETag;
    // Build key to retrieve item
    final Map<String, AttributeValue> resourceKey = new HashMap<String, AttributeValue>();
    resourceKey.put(MarsDynamoDBManager.RESOURCE_TABLE_HASH_KEY, new AttributeValue(resource));
    // Get item
    final GetItemResult result = dynamoDB.getItem(table, resourceKey);
    final Map<String, AttributeValue> item = result.getItem();
    if (item != null && item.containsKey(ETAG_KEY)) {
        // Item was found and contains ETag
        oldETag = item.get(ETAG_KEY).getS();
    } else {
        // Item was not found or did not contain ETag
        oldETag = null;
    }
    return oldETag;
}
 

public static void retrieveItem(String threadId, String replyDateTime) throws IOException {
    HashMap<String, AttributeValue> key = new HashMap<String, AttributeValue>();
    key.put("Id", new AttributeValue().withS(threadId));
    key.put("ReplyDateTime", new AttributeValue().withS(replyDateTime));
    
    GetItemRequest getReplyRequest = new GetItemRequest()
        .withTableName(tableName)
        .withKey(key)
        .withConsistentRead(true);
    
    GetItemResult getReplyResult = client.getItem(getReplyRequest);
    
    // Decompress the reply message and print
    Map<String, AttributeValue> reply = getReplyResult.getItem();
    String message = decompressString(reply.get("ExtendedMessage").getB());
    System.out.println("Reply message:\n"
        + " Id: " + reply.get("Id").getS() + "\n" 
        + " ReplyDateTime: " + reply.get("ReplyDateTime").getS() + "\n" 
        + " PostedBy: " + reply.get("PostedBy").getS() + "\n"
        + " Message: " + reply.get("Message").getS() + "\n"
        + " ExtendedMessage (decompressed): " + message);
}
 

@Override
public void afterResponse(Request<?> request, Response<?> response) {
    /*
     * The following is a hit and miss for multi-threaded clients as the
     * cache size is only 50 entries
     */
    String awsRequestId = dynamoDBClient.getCachedResponseMetadata(request.getOriginalRequest()).getRequestId();
    logger.info("AWS RequestID: " + awsRequestId);

    /*
     * Here you could inspect and alter the response object to see how your
     * application behaves for specific data
     */
    if (request.getOriginalRequest() instanceof GetItemRequest) {
        GetItemResult result = (GetItemResult) response.getAwsResponse();

        Map<String, AttributeValue> item = result.getItem();

        if (item.get("name").getS().equals("Airplane")) {

            // Alter the item
            item.put("name", new AttributeValue("newAirplane"));
            item.put("new attr", new AttributeValue("new attr"));

            // Add some delay
            try {
                Thread.sleep(500);
            }
            catch (InterruptedException ie) {
                logger.info(ie);
                throw new RuntimeException(ie);
            }
        }
    }
}
 

private EntryList extractEntriesFromGetItemResult(final GetItemResult result, final StaticBuffer sliceStart, final StaticBuffer sliceEnd, final int limit) {
    final Map<String, AttributeValue> item = result.getItem();
    List<Entry> filteredEntries = Collections.emptyList();
    if (null != item) {
        item.remove(Constants.JANUSGRAPH_HASH_KEY);
        filteredEntries = new EntryBuilder(item)
                .slice(sliceStart, sliceEnd)
                .limit(limit)
                .buildAll();
    }
    return StaticArrayEntryList.of(filteredEntries);
}
 

@Override
public void afterResponse(Request<?> request, Response<?> response)
{
    /*
     * The following is a hit and miss for multi-threaded clients as the
     * cache size is only 50 entries
     */
    String awsRequestId = dynamoDBClient.getCachedResponseMetadata(request.getOriginalRequest()).getRequestId();
    logger.info("AWS RequestID: " + awsRequestId);

    /*
     * Here you could inspect and alter the response object to see how your
     * application behaves for specific data
     */
    if (request.getOriginalRequest() instanceof GetItemRequest)
    {
        GetItemResult result = (GetItemResult) response.getAwsResponse();

        Map<String, AttributeValue> item = result.getItem();

        if (item.get("name").getS().equals("Airplane"))
        {

            // Alter the item
            item.put("name", new AttributeValue("newAirplane"));
            item.put("new attr", new AttributeValue("new attr"));

            // Add some delay
            try
            {
                Thread.sleep(500);
            }
            catch (InterruptedException ie)
            {
                logger.info(ie);
                throw new RuntimeException(ie);
            }
        }
    }
}
 

protected Map<String, AttributeValue> getItem(String tableName, Map<String, AttributeValue> key) {
    GetItemResult result = dynamodb.getItem(new GetItemRequest()
        .withTableName(tableName)
        .withKey(key)
        .withReturnConsumedCapacity(ReturnConsumedCapacity.TOTAL)
        .withConsistentRead(true));
    return result.getItem();
}
 

protected static Map<String, AttributeValue> getItem(TransactionManager txManager, String tableName, Map<String, AttributeValue> key) {
    GetItemRequest getRequest = new GetItemRequest()
        .withTableName(tableName)
        .withConsistentRead(true)
        .withKey(key);
    GetItemResult getResult = txManager.getClient().getItem(getRequest);
    return getResult.getItem();
}
 

private void checkExpectedValues(String tableName,
        Map<String, AttributeValue> itemKey,
        Map<String, ExpectedAttributeValue> expectedValues) {
    if (expectedValues != null && !expectedValues.isEmpty()) {
        for (Map.Entry<String, ExpectedAttributeValue> entry : expectedValues.entrySet()) {
            if ((entry.getValue().isExists() == null || entry.getValue().isExists() == true)
                    && entry.getValue().getValue() == null) {
                throw new IllegalArgumentException("An explicit value is required when Exists is null or true, "
                        + "but none was found in expected values for item with key " + itemKey +
                        ": " + expectedValues);
            }
        }

        // simulate by loading the item and checking the values;
        // this also has the effect of locking the item, which gives the
        // same behavior
        GetItemResult result = getItem(new GetItemRequest()
                .withAttributesToGet(expectedValues.keySet())
                .withKey(itemKey)
                .withTableName(tableName));
        Map<String, AttributeValue> item = result.getItem();
        try {
            checkExpectedValues(expectedValues, item);
        } catch (ConditionalCheckFailedException e) {
            throw new ConditionalCheckFailedException("Item " + itemKey + " had unexpected attributes: " + e.getMessage());
        }
    }
}