@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;
}
@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;
}