private Map<String, AttributeValue> getConsistentInternal(
String tableName, Key key, int attempt) {
GetItemRequest request = new GetItemRequest(tableName, key);
request.setConsistentRead(true);
try {
GetItemResult result = ddb.getItem(request);
Map<String, AttributeValue> attributes = result.getItem();
if (attributes == null || attributes.isEmpty()) {
return null;
}
return attributes;
} catch (AmazonServiceException e) {
if (DynamoDBUtil.AWS_ERR_CODE_RESOURCE_NOT_FOUND.equals(e.getErrorCode())) {
throw new IllegalArgumentException("no such table: " + tableName, e);
} else if (DynamoDBUtil.AWS_STATUS_CODE_SERVICE_UNAVAILABLE == e.getStatusCode()) {
// retry after a small pause
DynamoDBUtil.sleepBeforeRetry(attempt);
attempt++;
return getConsistentInternal(tableName, key, attempt);
} else {
throw new DataStoreOperationException(
"problem with table: " + tableName + ", key: " + key, e);
}
}
}
@Override
public int read(
String table, String key, Set<String> fields, HashMap<String, ByteIterator> result) {
logger.debug("readkey: " + key + " from table: " + table);
GetItemRequest req = new GetItemRequest(table, createPrimaryKey(key));
req.setAttributesToGet(fields);
req.setConsistentRead(consistentRead);
GetItemResult res = null;
try {
res = dynamoDB.getItem(req);
} catch (AmazonServiceException ex) {
logger.error(ex.getMessage());
return SERVER_ERROR;
} catch (AmazonClientException ex) {
logger.error(ex.getMessage());
return CLIENT_ERROR;
}
if (null != res.getItem()) {
result.putAll(extractResult(res.getItem()));
logger.debug("Result: " + res.toString());
}
return OK;
}
// TODO: test out put item expected and return value
@Test
public void getItemTest() {
AttributeValue hash = createItem(tableName);
GetItemRequest request = new GetItemRequest().withTableName(tableName);
request.setKey(new Key().withHashKeyElement(hash));
GetItemResult res = getClient().getItem(request);
Assert.assertNotNull(res.getItem());
Assert.assertEquals(res.getItem().get("id"), hash);
}
@Test
public void getItemWithoutKeyTest() {
GetItemRequest request = new GetItemRequest();
request.setTableName(tableName);
try {
getClient().getItem(request);
Assert.assertTrue(false); // Should have thrown an exception
} catch (AmazonServiceException ase) {
}
}
@Test
public void getItemWithoutTableNameTest() {
GetItemRequest request = new GetItemRequest();
request.setKey(new Key().withHashKeyElement(new AttributeValue().withNS("123")));
try {
getClient().getItem(request);
Assert.assertTrue(false); // Should have thrown an exception
} catch (AmazonServiceException ase) {
}
}
@Override
public int scan(
String table,
String startkey,
int recordcount,
Set<String> fields,
Vector<HashMap<String, ByteIterator>> result) {
logger.debug("scan " + recordcount + " records from key: " + startkey + " on table: " + table);
/*
* on DynamoDB's scan, startkey is *exclusive* so we need to
* getItem(startKey) and then use scan for the res
*/
GetItemRequest greq = new GetItemRequest(table, createPrimaryKey(startkey));
greq.setAttributesToGet(fields);
GetItemResult gres = null;
try {
gres = dynamoDB.getItem(greq);
} catch (AmazonServiceException ex) {
logger.error(ex.getMessage());
return SERVER_ERROR;
} catch (AmazonClientException ex) {
logger.error(ex.getMessage());
return CLIENT_ERROR;
}
if (null != gres.getItem()) {
result.add(extractResult(gres.getItem()));
}
int count = 1; // startKey is done, rest to go.
Key startKey = createPrimaryKey(startkey);
ScanRequest req = new ScanRequest(table);
req.setAttributesToGet(fields);
while (count < recordcount) {
req.setExclusiveStartKey(startKey);
req.setLimit(recordcount - count);
ScanResult res = null;
try {
res = dynamoDB.scan(req);
} catch (AmazonServiceException ex) {
logger.error(ex.getMessage());
ex.printStackTrace();
return SERVER_ERROR;
} catch (AmazonClientException ex) {
logger.error(ex.getMessage());
ex.printStackTrace();
return CLIENT_ERROR;
}
count += res.getCount();
for (Map<String, AttributeValue> items : res.getItems()) {
result.add(extractResult(items));
}
startKey = res.getLastEvaluatedKey();
}
return OK;
}