public boolean deleteAllItems(String tableName) throws DataAccessException {
ScanRequest request = new ScanRequest().withTableName(tableName);
boolean deleted = false;
ScanResult result = ddb.scan(request);
for (Map<String, AttributeValue> item : result.getItems()) {
Key key = DynamoDBUtil.getIdKey(item);
deleteItem(tableName, key);
deleted = true;
}
// keep repeating until we get through all matched items
Key lastKeyEvaluated = null;
do {
lastKeyEvaluated = result.getLastEvaluatedKey();
if (lastKeyEvaluated != null) {
request = new ScanRequest(tableName).withExclusiveStartKey(lastKeyEvaluated);
result = ddb.scan(request);
for (Map<String, AttributeValue> item : result.getItems()) {
Key key = DynamoDBUtil.getIdKey(item);
deleteItem(tableName, key);
deleted = true;
}
}
} while (lastKeyEvaluated != null);
return deleted;
}
@Override
public void onScanResult(int callbackType, ScanResult result) {
Log.i("callbackType", String.valueOf(callbackType));
Log.i("result", result.toString());
BluetoothDevice btDevice = result.getDevice();
connectToDevice(btDevice);
}
private List<Map<String, AttributeValue>> scanInternal(
String tableName, Map<String, Condition> filter, int max, int attempt) {
LinkedList<Map<String, AttributeValue>> items = new LinkedList<Map<String, AttributeValue>>();
try {
ScanRequest request = new ScanRequest(tableName).withScanFilter(filter);
ScanResult result = ddb.scan(request);
items.addAll(result.getItems());
// keep repeating until we get through all matched items
Key lastKeyEvaluated = null;
do {
lastKeyEvaluated = result.getLastEvaluatedKey();
if (lastKeyEvaluated != null) {
request =
new ScanRequest(tableName)
.withScanFilter(filter)
.withExclusiveStartKey(lastKeyEvaluated);
result = ddb.scan(request);
items.addAll(result.getItems());
}
} while (lastKeyEvaluated != null && items.size() < max);
// truncate if needed
while (items.size() > max) {
items.removeLast();
}
return items;
} 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 scanInternal(tableName, filter, max, attempt);
} else {
throw new DataStoreOperationException(
"problem with table: " + tableName + ", filter: " + filter, e);
}
}
}
@Override
protected void innerScanContainerShallow(
final BeanObjectContainer container, final ScanResult result) {
for (final Field field : container.getType().getType().getFields()) {
result.addPropertyField(
new SimplePropertyBeanPathElement(
getContext(), container, new BeanObjectAccessor(getContext(), container, field)));
}
for (final Method method : container.getType().getType().getMethods()) {
if (BeanPathStrings.startsWithAny(
method.getName(), BeanPathReflections.PROPERTY_METHOD_PREFIXES)) {
result.addPropertyMethod(
new SimplePropertyBeanPathElement(
getContext(), container, new BeanObjectAccessor(getContext(), container, method)));
} else {
result.addActionMethod(
new SimpleActionBeanPathElement(
getContext(), container, new BeanObjectAccessor(getContext(), container, method)));
}
}
}
@Override
public void onBatchScanResults(List<ScanResult> results) {
for (ScanResult sr : results) {
Log.i("ScanResult - Results", sr.toString());
}
}
/** @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) */
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String category = request.getParameter("category");
HashMap<String, Condition> scanFilter = new HashMap<String, Condition>();
Condition condition =
new Condition()
.withComparisonOperator(ComparisonOperator.NE.toString())
.withAttributeValueList(new AttributeValue().withN("0"));
Condition condition2 =
new Condition()
.withComparisonOperator(ComparisonOperator.NE.toString())
.withAttributeValueList(new AttributeValue().withN("0"));
Condition condition3 = new Condition().withComparisonOperator(ComparisonOperator.CONTAINS);
scanFilter.put("geoLat", condition);
scanFilter.put("geoLng", condition2);
if (category != null && !category.isEmpty()) {
condition3.withAttributeValueList(new AttributeValue().withS(category));
scanFilter.put("category", condition3);
}
// String queueUrl = SQS.getQueueUrl(new GetQueueUrlRequest(SQS_QUEUE_NAME)).getQueueUrl();
String tableName = DYNAMODB_TABLE_NAME;
ScanRequest scanRequest = new ScanRequest(tableName).withScanFilter(scanFilter);
ScanResult scanResult = DYNAMODB.scan(scanRequest);
int size = scanResult.getItems().size();
ArrayList<HashMap<String, String>> tweets = new ArrayList<HashMap<String, String>>();
for (int i = 0; i < size; i++) {
// Get latitude, longitude, content, username, created (long), category, sentiment
String categorydb = "no category";
String sentiment = "no sentiment";
if (scanResult.getItems().get(i).get("category") != null) {
categorydb = scanResult.getItems().get(i).get("category").getS();
sentiment = scanResult.getItems().get(i).get("sentiment").getS();
String lat = scanResult.getItems().get(i).get("geoLat").getN();
String lng = scanResult.getItems().get(i).get("geoLng").getN();
String content = scanResult.getItems().get(i).get("content").getS();
String username = scanResult.getItems().get(i).get("username").getS();
String created = scanResult.getItems().get(i).get("createdLong").getN();
String createdDate = scanResult.getItems().get(i).get("createdDate").getS();
// Format date.
DateFormat fromFormat = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");
DateFormat toFormat = new SimpleDateFormat("MMM dd · k:mm z");
Date date;
String createdstr;
try {
date = fromFormat.parse(createdDate);
createdstr = toFormat.format(date);
} catch (ParseException e) {
createdstr = createdDate;
}
// Create tweet hash.
HashMap<String, String> tweet = new HashMap<String, String>();
tweet.put("lat", lat);
tweet.put("lng", lng);
tweet.put("content", content);
tweet.put("username", username);
tweet.put("category", categorydb);
tweet.put("sentiment", sentiment);
tweet.put("created", created);
tweet.put("createdstr", createdstr);
// Order tweet by time created. Most recent at the top of the list.
int position = 0;
while (position < tweets.size()
&& Long.parseLong(tweets.get(position).get("created")) > Long.parseLong(created)) {
position++;
}
tweets.add(position, tweet);
}
// else {
// Send tweet with blank category for sentimental processing
// String id = scanResult.getItems().get(i).get("id").getS();
// SQS.sendMessage(new SendMessageRequest(queueUrl, id));
// }
}
// Log result.
System.out.println("Successfully handled GET request.");
if (category != null) {
System.out.println("category:" + category);
}
System.out.println("size: " + tweets.size());
// Convert object to JSON format.
String json = new Gson().toJson(tweets);
response.setContentType("application/json");
response.setCharacterEncoding("UTF-8");
response.getWriter().write(json);
}