I'm at an impasse on this ever-present autocomplete widget in the Zoho app that I'm to test. It pops up on the CRM pages under test, and to handle it, I had the following util method:
public final class GeneralWebUIUtils {
// ... other utils
public static void HandleAutoComplete(TestObject textField, String input, TestObject loader, TestObject dropdownOption, boolean doScroll = false) {
WebUI.click(textField)
WebUI.setText(textField, input)
TimeLoggerUtil.LogAction({
WebUI.waitForElementVisible(loader, 3)
// TODO: somehow this is not working for state; // it ends up selecting the first dropdown value
return WebUI.waitForElementNotVisible(loader, 3)
},
"Loader",
"appear and disappear");
// TODO: do we really need if-condition here?
if (doScroll) {
this.ScrollDropdownOptionIntoView(dropdownOption)
}
WebUI.waitForElementVisible(dropdownOption, 3, FailureHandling.STOP_ON_FAILURE)
WebUI.click(dropdownOption)
}
public static void ScrollDropdownOptionIntoView(TestObject to) {
WebUI.executeJavaScript("arguments[0].scrollIntoView({block: 'center'})", [WebUiCommonHelper.findWebElement(to, 1)])
}
// ... other util methods
}
This seemed like the answer, until I have been dealing with, off and on for several month...
...it select "the wrong" dropdown option! For example, on a membership category autocomplete, we type in "Membership", and it would select [some other dropdown option with "Membership" in the name], before the first member category dropdown option became available.
Last night, I was up til 2am working on this and test cases that were using it. I ended up changing the code to:
public static void HandleAutoComplete(TestObject textField, String input, TestObject loader, TestObject dropdownOption, boolean doScroll = false) throws StepFailedException {
WebUI.click(textField)
WebUI.setText(textField, input)
TimeLoggerUtil.LogAction({
return WebUI.waitForElementNotVisible(loader, 3)
},
"Loader",
"disappear");
// TODO: do we really need if-condition here?
if (doScroll) {
this.ScrollDropdownOptionIntoView(dropdownOption)
}
TimeLoggerUtil.LogAction({
WebUI.waitForElementVisible(dropdownOption, 3);
return this.WaitForElementHasText(dropdownOption, input, 5, FailureHandling.STOP_ON_FAILURE);
},
"Dropdown option",
"become visible")
WebUI.verifyElementText(dropdownOption, input)
WebUI.click(dropdownOption)
}
public static boolean WaitForElementCondition(Closure<Boolean> onCheckCondition, TestObject to, int timeOut, FailureHandling failureHandling = FailureHandling.STOP_ON_FAILURE) {
final long startTime = System.currentTimeMillis()
boolean isConditionSatisfied = false;
while ((System.currentTimeMillis() < startTime + timeOut * 1000) && (!isConditionSatisfied)) {
isConditionSatisfied = onCheckCondition(to);
}
if ((!isConditionSatisfied) && (failureHandling.equals(FailureHandling.STOP_ON_FAILURE))) {
KeywordUtil.markFailedAndStop("Condition for TestObject '${to.getObjectId()}' not met after ${(System.currentTimeMillis() - startTime) / 1000} seconds");
}
return isConditionSatisfied;
}
public static boolean WaitForElementHasText(TestObject to, String expectedText, int timeOut, FailureHandling failureHandling = FailureHandling.STOP_ON_FAILURE) {
return this.WaitForElementCondition({ TestObject testObj ->
return WebUI.getText(testObj).contains(expectedText);
},
to,
timeOut,
failureHandling);
}
This is way the hell faster, and instead of silently doing incorrect behavior (i.e. selecting the wrong dropdown option), it will throw exception. It should just work!!! (It seems like the actual dropdown option isn't ready to be checked by the time we go to check it...)
I tried remedying it by tweaking WaitForElementHasText():
public static boolean WaitForElementHasText(TestObject to, String expectedText, int timeOut, FailureHandling failureHandling = FailureHandling.STOP_ON_FAILURE) {
return this.WaitForElementCondition({ TestObject testObj ->
return WebUI.verifyElementPresent(testObj, 1) && WebUI.getText(testObj).contains(expectedText);
},
to,
timeOut,
failureHandling);
}
No dice. It will still sometimes fail, and there doesn't seem to be a damn thing I can do about it....
....or is there?
How, outside of switching to modal view, which is more complicated to handle, can we handle the autocomplete once and for all?
No matter how hard I tried, I couldn't solve this the traditional way: using strategy patterns.
Why? Because, when I went to log the initial states of dropdownOption and loader, they were the exact same, regardless of whether the autocomplete handler was going to end up succeeding, or failing.
It looks like I have no control over the dropdownOption "flickers" even after we wait on it to exist!
So, I had to get creative:
public static boolean WaitForElementCondition(Closure<Boolean> onCheckCondition, Closure onContinue, TestObject to, int timeOut, FailureHandling failureHandling = FailureHandling.STOP_ON_FAILURE) {
final long startTime = System.currentTimeMillis()
boolean isConditionSatisfied = false;
while ((System.currentTimeMillis() < startTime + timeOut * 1000) && (!isConditionSatisfied)) {
isConditionSatisfied = onCheckCondition(to);
onContinue(isConditionSatisfied, to);
}
if ((!isConditionSatisfied) && (failureHandling.equals(FailureHandling.STOP_ON_FAILURE))) {
KeywordUtil.markFailedAndStop("Condition for TestObject '${to.getObjectId()}' not met after ${(System.currentTimeMillis() - startTime) / 1000} seconds");
}
return isConditionSatisfied;
}
public static boolean WaitForElementHasText(TestObject to, String expectedText, int timeOut, FailureHandling failureHandling = FailureHandling.STOP_ON_FAILURE) {
return this.WaitForElementCondition({ TestObject testObj ->
return WebUI.getText(testObj).contains(expectedText);
},
{ boolean success, TestObject tObj ->
if (!success) {
WebUI.waitForElementNotPresent(tObj, 1);
WebUI.waitForElementPresent(tObj, timeOut);
}
},
to,
timeOut,
failureHandling);
}
re-ran the test several times, and all was well!
Related
I have this next class:
#Service
public class BusinessService {
#Autowired
private RedisService redisService;
private void count() {
String redisKey = "MyKey";
AtomicInteger counter = null;
if (!redisService.isExist(redisKey))
counter = new AtomicInteger(0);
else
counter = redisService.get(redisKey, AtomicInteger.class);
try {
counter.incrementAndGet();
redisService.set(redisKey, counter, false);
logger.info(String.format("Counter incremented by one. Current counter = %s", counter.get()));
} catch (JsonProcessingException e) {
logger.severe(String.format("Failed to increment counter."));
}
}
// Remaining code
}
and this this my RedisService.java class
#Service
public class RedisService {
private Logger logger = LoggerFactory.getLogger(RedisService.class);
#Autowired
private RedisConfig redisConfig;
#PostConstruct
public void postConstruct() {
try {
String redisURL = redisConfig.getUrl();
logger.info("Connecting to Redis at " + redisURL);
syncCommands = RedisClient.create(redisURL).connect().sync();
} catch (Exception e) {
logger.error("Exception connecting to Redis: " + e.getMessage(), e);
}
}
public boolean isExist(String redisKey) {
return syncCommands.exists(new String[] { redisKey }) == 1 ? true : false;
}
public <T extends Serializable> void set(String key, T object, boolean convertObjectToJson) throws JsonProcessingException {
if (convertObjectToJson)
syncCommands.set(key, writeValueAsString(object));
else
syncCommands.set(key, String.valueOf(object));
}
// Remaining code
}
and this is my test class
#Mock
private RedisService redisService;
#Spy
#InjectMocks
BusinessService businessService = new BusinessService();
#Before
public void setup() {
MockitoAnnotations.initMocks(this);
}
#Test
public void myTest() throws Exception {
for (int i = 0; i < 50; i++)
Whitebox.invokeMethod(businessService, "count");
// Remaining code
}
my problem is the counter always equals to one in logs when running tests
Counter incremented by one. Current counter = 1(printed 50 times)
and it should print:
Counter incremented by one. Current counter = 1
Counter incremented by one. Current counter = 2
...
...
Counter incremented by one. Current counter = 50
this means the Redis mock always passed as a new instance to BusinessService in each method call inside each loop, so how I can force this behavior to become only one instance used always for Redis inside the test method ??
Note: Above code is just a sample to explain my problem, but it's not a complete code.
Your conclusion that a new RedisService is somehow created in each iteration is wrong.
The problem is that it is a mock object for which you haven’t set any behaviours, so it responds with default values for each method call (null for objects, false for bools, 0 for ints etc).
You need to use Mockito.when to set behaviour on your mocks.
There is some additional complexity caused by the fact that:
you run the loop multiple times, and behaviour of the mocks differ between first and subsequent iterations
you create cached object in method under test. I used doAnswer to capture it.
You need to use doAnswer().when() instead of when().thenAnswer as set method returns void
and finally, atomicInt variable is modified from within the lambda. I made it a field of the class.
As the atomicInt is modified each time, I again used thenAnswer instead of thenReturn for get method.
class BusinessServiceTest {
#Mock
private RedisService redisService;
#InjectMocks
BusinessService businessService = new BusinessService();
AtomicInteger atomicInt = null;
#BeforeEach
public void setup() {
MockitoAnnotations.initMocks(this);
}
#Test
public void myTest() throws Exception {
// given
Mockito.when(redisService.isExist("MyKey"))
.thenReturn(false)
.thenReturn(true);
Mockito.doAnswer((Answer<Void>) invocation -> {
atomicInt = invocation.getArgument(1);
return null;
}).when(redisService).set(eq("MyKey"), any(AtomicInteger.class), eq(false));
Mockito.when(redisService.get("MyKey", AtomicInteger.class))
.thenAnswer(invocation -> atomicInt);
// when
for (int i = 0; i < 50; i++) {
Whitebox.invokeMethod(businessService, "count");
}
// Remaining code
}
}
Having said that, I still find your code questionable.
You store AtomicInteger in Redis cache (by serializing it to String). This class is designed to be used by multiple threads in a process, and the threads using it the same counter need to share the same instance. By serializing it and deserializing on get, you are getting multiple instances of the (conceptually) same counter, which, to my eyes, looks like a bug.
smaller issue: You shouldn't normally test private methods
2 small ones: there is no need to instantiate the field annotated with #InjectMocks. You don't need #Spy as well.
I'm pretty new with concurency and I'v hit the wall several times already.
Code pretty much describes everything, but just to clarify: user press the button, application send query to db and in the meantime statusLabel is set to:
Veryfing.
200ms
Veryfing..
200ms
Veryfing...
200ms
Result of query
I'v managed to achieve that, but now, I need to use result of query in another class (if it succeed, another window is opened), but It never does. I came to conclusion that it just checks the result before Task is finished so result is always false, I have no idea how to work around this, so another class checks condition once Task is done.
First, my Authorization class
public class Authorization {
private static String query = "";
private static boolean isValid;
private static Task<Void> task;
public static void verifyLogin(String username, String password) throws SQLException{
Status.get().unbind();
isValid = false;
task = new Task<Void>() {
#Override
protected Void call() throws SQLException {
while(!isCancelled()) {
try {
updateMessage("Weryfikacja.");
Thread.sleep(200);
updateMessage("Weryfikacja..");
Thread.sleep(200);
updateMessage("Weryfikacja...");
Thread.sleep(200);
if(username.equals("") || password.equals("")) {
task.cancel();
updateMessage("Pola nie mogą być puste");
} else {
query = "SELECT login FROM users WHERE login = ?";
Query.execute(query, username);
if(!Query.resultSet.next()) {
task.cancel();
updateMessage("Nie ma takiego użytkownika");
} else {
query = "SELECT password FROM users WHERE login = ?";
Query.execute(query, username);
if(Query.resultSet.next()) {
String passwordValue = Query.resultSet.getString(1);
if(!password.equals(passwordValue)) {
task.cancel();
updateMessage("Podane hasło jest błędne");
} else {
task.cancel();
updateMessage("");
isValid = true;
}
}
}
}
} catch(InterruptedException e) {
if(isCancelled()) {
break;
}
}
}
return null;
}
};
Status.get().bind(task.messageProperty());
new Thread(task).start();
}
public static boolean isValid() {
return isValid;
}
}
called from another class
private void login() {
if( SqlConnection.isConnected()) {
try{
Authorization.verifyLogin(String.valueOf(loginInput.getText()), String.valueOf(passwordInput.getText()));
if(Authorization.isValid()) {
//should go to next menu
//but never does
}
} catch (SQLException e) {
e.printStackTrace();
Debug.log(e.toString());
}
}
}
edit#
Sorry for polish in updateMessage().
Your verifyLogin() method simply starts the verification process in another thread, and then exits immediately. The isValid flag will not be changed until that thread completes, which happens quite a lot later. If you want to do the verification process and then do something else, it doesn't really make sense to manage the threads in verifyLogin().
I don't really understand a lot of what your code is supposed to be doing; you have a while(...) loop, which as far as I can tell can only be executed once (so is redundant). You also seem to execute two SQL queries which are essentially the same. (The first checks to see if there is a row with a certain condition, then if there is, the second retrieves that row. Why not just retrieve the row and check if it is there?)
I would refactor this so that the validateLogin() method doesn't handle the threading at all, and just returns the result of the validation (e.g. a status string, but maybe something else would be appropriate).
/**
* #return An empty string if the login is valid, or an error message otherwise
*/
public static String verifyLogin(String username, String password) throws SQLException{
isValid = false ;
if(username.equals("") || password.equals("")) {
return "Pola nie mogą być puste";
}
query = "SELECT login, password FROM users WHERE login = ?";
Query.execute(query, username);
if(!Query.resultSet.next()) {
return "Nie ma takiego użytkownika";
}
String passwordValue = Query.resultSet.getString(2);
if(!password.equals(passwordValue)) {
return "Podane hasło jest błędne" ;
}
isValid = true;
return "" ;
}
Now I would manage the threads from the login() method. That way you can use the task's onSucceeded handler to execute code when the task completes:
private void login() {
if( SqlConnection.isConnected()) {
Task<String> verifyTask = new Task<String>() {
#Override
protected String call() throws SQLException {
return Authorization.verifyLogin(loginInput.getText(), passwordInput.getText());
}
};
// probably better to use a progress indicator or similar here, but:
Animation animation = new Timeline(
new KeyFrame(Duration.ZERO, e -> Status.get().set("Weryfikacja.")),
new KeyFrame(Duration.millis(200), e -> Status.get().set("Weryfikacja..")),
new KeyFrame(Duration.millis(400), e -> Status.get().set("Weryfikacja...")),
new KeyFrame(Duration.millis(600)));
animation.setCycleCount(Animation.INDEFINITE);
verifyTask.setOnSucceeded(event -> {
animation.stop();
Status.get().set(verifyTask.getValue());
if(Authorization.isValid()) { // or if (verifyTask.getValue().isEmpty())
// go to next menu
}
});
verifyTask.setOnFailed(event -> {
animation.stop();
verifyTask.getException().printStackTrace();
Debug.log(verifyTask.getException().toString());
}
animation.play();
new Thread(verifyTask()).start();
}
}
I'm attempting to instrument a cassandra driver and in particular need to modify a ResultSet class to hang on to some information. In order to do this I need to modify the code where the instance is being allocated, which is a static method in another class. The code has this snippet in it:
return r.metadata.pagingState == null
? new SinglePage(columnDefs, tokenFactory, protocolVersion, columnDefs.codecRegistry, r.data, info)
: new MultiPage(columnDefs, tokenFactory, protocolVersion, columnDefs.codecRegistry, r.data, info, r.metadata.pagingState, session);
It also has other returns within the method. So my thought was to use an AdviceAdapter on this method and use the onMethodExit(). However, my method was never called. That seems absurd since.. the method has to be returning! After a little debugging, I find the visitInsn() in the AdviceAdapter class is being called just once, with an opcode of IALOAD (load an int from an array?).
I guess my question is.. what the hell is going on? Heh.. sorry, bonked my head on my desk a few too many times today.
EDIT: I changed my class to be a simple MethodVisitor just to see if could see more opcodes, and indeed I do! I see it all! I just no longer have access to dup(). :(
I have used an EmailAdviceAdaptor (for javax/mail/Transport) in one of my project, Code is given below. Hope this code will help to resolve your issue.
package com.mail.agent.adapter;
import com.mail.jtm.BTMConstants;
import com.mail.org.objectweb.asm.Label;
import com.mail.org.objectweb.asm.MethodVisitor;
import com.mail.org.objectweb.asm.Opcodes;
import com.mail.org.objectweb.asm.Type;
import com.mail.org.objectweb.asm.commons.AdviceAdapter;
public class MyEmailAdviceAdapter extends AdviceAdapter {
private String methodName;
private String className;
private String description;
private static final String MAIL_SEND_METHOD1_DESC="(Ljavax/mail/Message;)V";
private static final String MAIL_SEND_METHOD2_DESC="(Ljavax/mail/Message;[Ljavax/mail/Address;)V";
private static final String MAIL_SENDMESSAGE_METHOD_DESC="(Ljavax/mail/Message;[Ljavax/mail/Address;)V";
private boolean isSendMethod;
private int okFlag = newLocal(Type.BOOLEAN_TYPE);
Label startFinally = new Label();
public MyEmailAdviceAdapter(int access , MethodVisitor mv , String methodName, String description, String className, int classFileVersion){
super(Opcodes.ASM5 , mv, access, methodName, description);
this.className = className;
this.methodName = methodName;
this.description = description;
this.isSendMethod = false;
if(methodName.equals("send")){
if( description.equals(MAIL_SEND_METHOD1_DESC) || description.equals(MAIL_SEND_METHOD2_DESC)){
isSendMethod = true;
}
}
else if(methodName.equals("sendMessage") && description.equals(MAIL_SENDMESSAGE_METHOD_DESC)){
isSendMethod = true;
}
}
public void visitCode() {
super.visitCode();
mv.visitLabel(startFinally);
}
protected void onMethodEnter(){
if(isSendMethod) {
mv.visitInsn(Opcodes.ICONST_0);
mv.visitVarInsn(ISTORE, okFlag);
mv.visitVarInsn(Opcodes.ALOAD, 0);
mv.visitLdcInsn(className);
mv.visitLdcInsn(methodName);
mv.visitLdcInsn(description);
mv.visitMethodInsn(Opcodes.INVOKESTATIC, "com/mail/agent/trace/MailTracer", "mailMethodBegin", "(Ljava/lang/Object;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;)Z"; , false);
mv.visitVarInsn(ISTORE, okFlag);
}
}
protected void onMethodExit(int opcode){
if(opcode!=ATHROW) {
onFinally(opcode);
}
}
public void visitMaxs(int maxStack, int maxLocals){
Label endFinally = new Label();
mv.visitTryCatchBlock(startFinally, endFinally, endFinally, null);
mv.visitLabel(endFinally);
onFinally(ATHROW);
mv.visitInsn(ATHROW);
mv.visitMaxs(maxStack, maxLocals);
}
private void onFinally(int opcode){
if(isSendMethod){
// If the method throws any exception
if(opcode == ATHROW){
mv.visitInsn(Opcodes.DUP);
mv.visitLdcInsn(className);
mv.visitLdcInsn(methodName);
mv.visitLdcInsn(description);
mv.visitVarInsn(ILOAD, okFlag);
mv.visitMethodInsn(Opcodes.INVOKESTATIC, "com/mail/agent/trace/MailTracer", "recordException", "(Ljava/lang/Object;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Z)V", false);
}
mv.visitLdcInsn(className);
mv.visitLdcInsn(methodName);
mv.visitLdcInsn(description);
mv.visitVarInsn(ILOAD, okFlag);
mv.visitLdcInsn(opcode);
mv.visitMethodInsn(Opcodes.INVOKESTATIC, "com/mail/agent/trace/MailTracer", "mailMethodEnd", "(Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;ZI)V", false);
}
}
}
How to navigate to the next page based on the return value from the method called inside the action attribute of the command button.
<af:button id="tt_b2"
rendered="#{attrs.nextRendered}"
partialSubmit="true"
action="#{attrs.backingBean.nextAction}"
text="Next"
disabled="#{attrs.nextDisabled}"/>
private static final String NEXT_NAVIGATION_ACTION = "controllerContext.currentViewPort.taskFlowContext.trainModel.getNext";
public String nextAction() {
if (validate()) {
updateModel();
return NEXT_NAVIGATION_ACTION;
}
return null;
}
The use case is done for train model, which is implemented based on this blog : http://javacollectibles.blogspot.co.uk/2014/10/adf-train-template.html
We need to define a generic next action in the template but the action should be called conditionally, based on whether all the validation checks has been passed on not.
Try using ADFUtils.invokeEl
public String nextAction() {
if (validate()) {
updateModel();
return (String)ADFUtils.invokeEL(NEXT_NAVIGATION_ACTION);
}
return null;
}
Its ain't necessary to hardcode any steps, you can query TaskFlowTrainModel
/**
* Navigates to the next stop in a train
* #return outcome string
*/
public String navigateNextStop() {
String nextStopAction = null;
ControllerContext controllerContext = ControllerContext.getInstance();
ViewPortContext currentViewPortCtx = controllerContext.getCurrentViewPort();
TaskFlowContext taskFlowCtx = currentViewPortCtx.getTaskFlowContext();
TaskFlowTrainModel taskFlowTrainModel = taskFlowCtx.getTaskFlowTrainModel();
TaskFlowTrainStopModel currentStop = taskFlowTrainModel.getCurrentStop();
TaskFlowTrainStopModel nextStop = taskFlowTrainModel.getNextStop(currentStop);
//is either null or has the value of outcome
return nextStopAction;
}
Full code of the sample can be found on the ADF Code Corner.
To navigate by taskflow outcomes you just need to provide exact outcome String as return of your method:
private static final String NEXT_NAVIGATION_ACTION = "next";
public String nextAction() {
if (validate()) {
updateModel();
return NEXT_NAVIGATION_ACTION;
}
return null;
}
Can you verify, you can do it in through phase listener.
Verify you condition in the phase listener and allow it to move ahead if it validates else stop the thread execution.
Below is the sample phase listener code.
public class MyPhaseListener implements PagePhaseListener{
public MyPhaseListener() {
super();
}
#Override
public void afterPhase(PagePhaseEvent pagePhaseEvent) {
if (pagePhaseEvent.getPhaseId() == Lifecycle.PREPARE_RENDER_ID ) {
// DO your logic here
}
}
#Override
public void beforePhase(PagePhaseEvent pagePhaseEvent) {
}
}
I got some questions regarding the use of threads, specially when you have to wait for a thread to be finished so you can perform other operations.
In my app, I use threads for operations such as http connections or when I read from or write to a RecordStore.
For example in the following class that I use to initialize my thread, I retrieve some customers from a webservice using the method called HttpQueryCustomers.
public class thrLoadCustomers implements Runnable {
private RMSCustomer mRMSCustomer;
private String mUrl;
public thrLoadCustomers(RMSCustomer rmsCust, String url) {
mRMSCustomer = rmsCust;
mUrl = url;
}
public void run() {
String jsonResultados = "";
try {
jsonResultados = HttpQueryCustomers();
} catch (IOException ex) {
//How to show a message from here??
} catch (SecurityException se) {
//How to show a message here??
} catch (NullPointerException npe) {
//How to show a message from here??
}
if (!jsonResultados.equals("")) {
try {
mRMSCustomer.save(jsonResultados);
} catch (RecordStoreException ex) {
//How to show a message from here???
}
}
}
public String HttpQueryCustomers() throws IOException,SecurityException,NullPointerException {
StringBuffer stringBuffer = new StringBuffer();
HttpConnection hc = null;
InputStream is = null;
System.out.println(mUrl);
try {
hc = (HttpConnection) Connector.open(mUrl);
if (hc.getResponseCode() == HttpConnection.HTTP_OK) {
is = hc.openInputStream();
int ch;
while ((ch = is.read()) != -1) {
stringBuffer.append((char) ch);
}
}
} finally {
is.close();
hc.close();
}
String jsonData = stringBuffer.toString();
return jsonData.toString();
}
}
Notice in the above class that I pass a parameter called rmsCust of the type RMSCustomer
RMSCustomer is a class that I use to handle all the operations related to RMS:
public class RMSCustomer {
private String mRecordStoreName;
private Customer[] mCustomerList;
public RMSCustomer(String recordStoreName) {
mRecordStoreName = recordStoreName;
}
public Customer[] getCustomers() {
return mCustomerList;
}
public Customer get(int index) {
return mCustomerList[index];
}
public void save(String data) throws RecordStoreException,JSONException,NullPointerException {
RecordStore rs = null;
int idNuevoRegistro;
String stringJSON;
try {
rs = RecordStore.openRecordStore(mRecordStoreName, true);
JSONArray js = new JSONArray(data);
//Set the size of the array
mCustomerList = new Customer[js.length()];
for (int i = 0; i < js.length(); i++) {
JSONObject jsObj = js.getJSONObject(i);
stringJSON = jsObj.toString();
idNuevoRegistro = addRecord(stringJSON, rs);
//Add a new Customer to the array
mCustomerList[i] = initializeCustomer(stringJSON, idNuevoRegistro);
}
} finally {
if (rs != null) {
rs.closeRecordStore();
}
}
}
public int addRecord(String stringJSON, RecordStore rs) throws JSONException,RecordStoreException {
byte[] raw = stringJSON.getBytes();
int idNuevoRegistro = rs.addRecord(raw, 0, raw.length);
return idNuevoRegistro;
}
public Customer initializeCustomer(String stringJSON, int idRecord) throws JSONException {
Customer c = new Customer();
JSONObject jsonObj = new JSONObject(stringJSON);
// Set Customer properties
//...
return c;
}
}
This class is used to show a list of customer and ,as you can see, it extends the List class and receives an array of Customers as a parameter.
public class ListCustomers extends List {
private final Customer[] mData;
public static ListCustomers create(Customer[] data) {
int i = 0;
for (; i < data.length; i++) {
if (data[i] == null) {
break;
}
}
String[] names = new String[i];
for (int j = 0; j < i; j++) {
names[j] = data[j].name;
}
return new ListCustomers(names, data);
}
protected ListCustomers(String names[], Customer[] data) {
super("List of Customer", IMPLICIT, names, null);
mData = data;
}
public Customer getSelectedObject() {
return mData[this.getSelectedIndex()];
}
}
Finally this is how I call the thread from the MIDlet (using all the 3 previous classes) when I want to show a List of Customers:
private void showCustomerList(String url) {
showWaitForm();
if (scrCustomerList == null) {
rmsCustomers = new RMSCustomer("rmsCustomers");
thrLoadCustomers load = new thrLoadCustomers(rmsCustomers, url);
Thread t = new Thread(load);
t.start();
try {
t.join();
} catch (InterruptedException ex) {
}
scrCustomerList = ListCustomers.create(rmsCustomers.getCustomers());
scrCustomerList.addCommand(cmdSelect);
scrCustomerList.addCommand(cmdBack);
scrCustomerList.setCommandListener(this);
}
mDisplay.setCurrent(scrCustomerList);
}
Now here's the problems I have :
The showWaitForm() doesn't work (it sets a form with a Gauge as the
Current form)
I don't know how to show all the exceptions that might be thrown from
within the thrLoadCustomers class.
I don't know whether using t.join() is the best choice
The last question is about something the book I'm reading says :
Threads, in particular, can be a scarce commodity. The MSA
specification requires that an application must be allowed to create
ten threads. Just because you can doesn’t mean you should. In general,
try to use the fewest resources possible so that your application will
run as smoothly as possible
This is the first time a use threads, and in my app I might have up to 10 threads (classes). However, I will only execute once thread at the time, will I be going against what the previous quotation says??
I hope I'm not asking too many questions. Thank you very much for your help.
P.D Much of the code I posted here wouldn't have been possible with the help of Gregor Ophey
Question #1 is about a different problem not related to threading, and for which very little code is shown. I'd suggest you to post a new dedicated question with proper explanation of the issue.
Questions #2 and #3: You could define a wrapper class like this:
public class WSResult {
private boolean success; //true if the WS call went ok, false otherwise
private String errorMessage; //Error message to display if the WS call failed.
private Object result; //Result, only if the WS call succeeded.
private boolean completed = false;
//TODO getter and setters methods here
}
In your screen, you can create an instance of result and wait for it:
WSResult result = new WSResult();
//Start thread here
new Thread(new LoadCustomersTask(result)).start();
//This is old school thread sync.
synchronized(result){
while(!result.isCompleted()){
result.wait();
}
}
//Here the thread has returned, and we can diaplay the error message if any
if(result.isSuccess()){
} else {
//Display result.getErrorMessage()
}
Then your runnable would be like this:
class LoadCustomersTask implements Runnable {
private final WSResult result;
public LoadCustomersTask(WSResult res){
result = res;
}
public void run(){
//Do the WS call
//If it went well
result.setSuccess(true);
result.setResult(jsonResultados);
//Else
result.setSuccess(false);
result.setErrorMessage("Your error message");
//In any case, mark as completed
result.setcompleted(true);
//And notify awaiting threads
synchronized(result){
result.notifyAll();
}
}
}
You can also do it with thread.join, but wait/notify is better because you not making the screen depend on the particular thread where the runnable runs. You can wait/notify on the result instance, as shown, or on the runnable if it is intended for a single use.
Question #4: Yes threads must not be abused, specially in JavaME where programs usually run in single core CPUs with a frecuency in the order of MHz. Try not to have more than 1-3 threads running at the same time. If you really need to, consider using a single thread for running all background tasks (a blocking queue).