/**
* Executes a batch of queries. You define the queries to execute by calling 'beginBatch' and then
* invoking the desired API methods that you want to execute as part of your batch as normal.
* Invoking this method will then execute the API calls you made in the interim as a single batch
* query.
*
* @param serial set to true, and your batch queries will always execute serially, in the same
* order in which your specified them. If set to false, the Facebook API server may execute
* your queries in parallel and/or out of order in order to improve performance.
* @return a list containing the results of the batch execution. The list will be ordered such
* that the first element corresponds to the result of the first query in the batch, and the
* second element corresponds to the result of the second query, and so on. The types of the
* objects in the list will match the type normally returned by the API call being invoked (so
* calling users_getLoggedInUser as part of a batch will place a Long in the list, and calling
* friends_get will place a Document in the list, etc.).
* <p>The list may be empty, it will never be null.
* @throws FacebookException
* @throws IOException
*/
public List<? extends Object> executeBatch(boolean serial) throws FacebookException {
List<String> clientResults = client.executeBatch(serial);
List<Object> result = new ArrayList<Object>();
for (String clientResult : clientResults) {
JSONArray doc;
try {
// Must ensure that JSONArray(String) constructor
// is called. JSONArray(Object) behaves differently.
doc = new JSONArray(clientResult);
} catch (JSONException ex) {
throw new RuntimeException("Error parsing client result", ex);
}
for (int count = 0; count < doc.length(); count++) {
try {
String response = (String) doc.get(count);
Object responseObject = JsonHelper.parseCallResult(response);
result.add(responseObject);
} catch (Exception ignored) {
result.add(null);
}
}
}
return result;
}
@SuppressWarnings("unchecked")
protected <T> T parseCallResult(Class<T> type, Object rawResponse) throws FacebookException {
log.debug("Facebook response: " + rawResponse);
Object out = JsonHelper.parseCallResult(rawResponse);
if (type == JSONArray.class && out instanceof JSONObject) {
JSONArray arr = new JSONArray();
JSONObject json = (JSONObject) out;
if (json.length() > 0) {
arr.put(json);
}
out = arr;
}
return (T) out;
}
