Example usage for com.amazonaws.services.dynamodbv2.document DynamoDB batchGetItem

Introduction

In this page you can find the example usage for com.amazonaws.services.dynamodbv2.document DynamoDB batchGetItem.

Prototype

@Override
    public BatchGetItemOutcome batchGetItem(BatchGetItemSpec spec) 

Source Link

Usage

From source file:org.apache.nifi.processors.aws.dynamodb.GetDynamoDB.java

License:Apache License

@Override
public void onTrigger(final ProcessContext context, final ProcessSession session) {
    List<FlowFile> flowFiles = session
            .get(context.getProperty(BATCH_SIZE).evaluateAttributeExpressions().asInteger());
    if (flowFiles == null || flowFiles.size() == 0) {
        return;/*from ww  w  .  j  av  a  2s  . co m*/
    }

    Map<ItemKeys, FlowFile> keysToFlowFileMap = new HashMap<>();

    final String table = context.getProperty(TABLE).evaluateAttributeExpressions().getValue();
    TableKeysAndAttributes tableKeysAndAttributes = new TableKeysAndAttributes(table);

    final String hashKeyName = context.getProperty(HASH_KEY_NAME).evaluateAttributeExpressions().getValue();
    final String rangeKeyName = context.getProperty(RANGE_KEY_NAME).evaluateAttributeExpressions().getValue();
    final String jsonDocument = context.getProperty(JSON_DOCUMENT).evaluateAttributeExpressions().getValue();

    for (FlowFile flowFile : flowFiles) {
        final Object hashKeyValue = getValue(context, HASH_KEY_VALUE_TYPE, HASH_KEY_VALUE, flowFile);
        final Object rangeKeyValue = getValue(context, RANGE_KEY_VALUE_TYPE, RANGE_KEY_VALUE, flowFile);

        if (!isHashKeyValueConsistent(hashKeyName, hashKeyValue, session, flowFile)) {
            continue;
        }

        if (!isRangeKeyValueConsistent(rangeKeyName, rangeKeyValue, session, flowFile)) {
            continue;
        }

        keysToFlowFileMap.put(new ItemKeys(hashKeyValue, rangeKeyValue), flowFile);

        if (rangeKeyValue == null || StringUtils.isBlank(rangeKeyValue.toString())) {
            tableKeysAndAttributes.addHashOnlyPrimaryKey(hashKeyName, hashKeyValue);
        } else {
            tableKeysAndAttributes.addHashAndRangePrimaryKey(hashKeyName, hashKeyValue, rangeKeyName,
                    rangeKeyValue);
        }
    }

    if (keysToFlowFileMap.isEmpty()) {
        return;
    }

    final DynamoDB dynamoDB = getDynamoDB();

    try {
        BatchGetItemOutcome result = dynamoDB.batchGetItem(tableKeysAndAttributes);

        // Handle processed items and get the json document
        List<Item> items = result.getTableItems().get(table);
        for (Item item : items) {
            ItemKeys itemKeys = new ItemKeys(item.get(hashKeyName), item.get(rangeKeyName));
            FlowFile flowFile = keysToFlowFileMap.get(itemKeys);

            if (item.get(jsonDocument) != null) {
                ByteArrayInputStream bais = new ByteArrayInputStream(item.getJSON(jsonDocument).getBytes());
                flowFile = session.importFrom(bais, flowFile);
            }

            session.transfer(flowFile, REL_SUCCESS);
            keysToFlowFileMap.remove(itemKeys);
        }

        // Handle unprocessed keys
        Map<String, KeysAndAttributes> unprocessedKeys = result.getUnprocessedKeys();
        if (unprocessedKeys != null && unprocessedKeys.size() > 0) {
            KeysAndAttributes keysAndAttributes = unprocessedKeys.get(table);
            List<Map<String, AttributeValue>> keys = keysAndAttributes.getKeys();

            for (Map<String, AttributeValue> unprocessedKey : keys) {
                Object hashKeyValue = getAttributeValue(context, HASH_KEY_VALUE_TYPE,
                        unprocessedKey.get(hashKeyName));
                Object rangeKeyValue = getAttributeValue(context, RANGE_KEY_VALUE_TYPE,
                        unprocessedKey.get(rangeKeyName));
                sendUnprocessedToUnprocessedRelationship(session, keysToFlowFileMap, hashKeyValue,
                        rangeKeyValue);
            }
        }

        // Handle any remaining items
        for (ItemKeys key : keysToFlowFileMap.keySet()) {
            FlowFile flowFile = keysToFlowFileMap.get(key);
            flowFile = session.putAttribute(flowFile, DYNAMODB_KEY_ERROR_NOT_FOUND,
                    DYNAMODB_KEY_ERROR_NOT_FOUND_MESSAGE + key.toString());
            session.transfer(flowFile, REL_NOT_FOUND);
            keysToFlowFileMap.remove(key);
        }

    } catch (AmazonServiceException exception) {
        getLogger().error("Could not process flowFiles due to service exception : " + exception.getMessage());
        List<FlowFile> failedFlowFiles = processServiceException(session, flowFiles, exception);
        session.transfer(failedFlowFiles, REL_FAILURE);
    } catch (AmazonClientException exception) {
        getLogger().error("Could not process flowFiles due to client exception : " + exception.getMessage());
        List<FlowFile> failedFlowFiles = processClientException(session, flowFiles, exception);
        session.transfer(failedFlowFiles, REL_FAILURE);
    } catch (Exception exception) {
        getLogger().error("Could not process flowFiles due to exception : " + exception.getMessage());
        List<FlowFile> failedFlowFiles = processException(session, flowFiles, exception);
        session.transfer(failedFlowFiles, REL_FAILURE);
    }
}

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