Should there be any specific order in which I should write the following :
public static void main() ?
In other words, can I re-shuffle public,static,void in any order ?
Why or Why not ?
I need to do a search in a map of maps and return the keys this element belong.
I think this implementation is very slow, can you help me to optimize it?.
I need to use TreeSet and I can't use contains because they use compareTo, and equals/compareTo pair are implemented in an incompatible way and I can't change that.
(sorry my bad english)
Map m = new TreeSet();
public String getKeys(Element element) {
for(Entry e : m.entrySet()) {
mapSubKey = e.getValue();
for(Entry e2 : mapSubKey.entrySet()) {
setElements = e2.getValue();
for(Element elem : setElements)
if(elem.equals(element)) return "Key: " + e.getKey() + " SubKey: " + e2.getKey();
}
}
}
Hello,
I have an object of CalendarEntry
I know that http://www.google.com/calendar/feeds/[email protected]/allcalendars/full is the feed url of all calendars
but how I can get this feed url from CalendarEntry instance?
Because I wanna post a new entry in a specified calendar and I need this url.
Thanks!
Hi All,
I have a text file with Tag - Value format data. I want to parse this file to form a Trie. What will be the best approach?
Sample of File: (String inside "" is a tag and '#' is used to comment the line.)
#Hi, this is a sample file.
"abcd" = 12;
"abcde" = 16;
"http" = 32;
"sip" = 21;
Process p;
String line;
String path;
String[] params = new String [3];
params[0] = "D:\\prog.exe";
params[1] = picA+".jpg";
params[2] = picB+".jpg";
try {
p = Runtime.getRuntime().exec(params);
BufferedReader input =
new BufferedReader
(new InputStreamReader(p.getInputStream()));
while ((line = input.readLine()) != null)
System.out.println(line);
input.close();
} catch (IOException e) {System.out.println(" procccess not read"+e);}
i don't get any error, just nothing
in cmd.exe prog.exe is working fine
What to improve in order to make this code working?
public static void main(String[] args) {
int x = 1 + + + + + + + + + 2;
System.out.println(x);
}
I can compile above method. Is there any explanation about the allowed multiple "+" operator?
Good Morning - it is school assignment, I am not asking for any source code (if you can provide any pesudo code it would be awesome).
Here is the problem :(
I have to create a term frequency table. It is not pure TF, I just need to count the words and write down.
I know basic steps to do it
1 - extract all terms (I can do it with file reader)
2 - remove repeating terms (I can do it with TreeMap)
The output of 2nd step would be
Niga, ponga, dinga, bitlo, etc.
3 - Now I have to see if there is any word in current file from above terms or not, if yes then I will count.
Now this is my problem, I stucked on step 3 :(
I have some idea how to count words with TreeMap (treemap.containskey etc.) but it would be global count not local count for each file :(
Any pseudo code?
I have one Map that contains some names and numbers
Map<String,Integer> abc = new TreeMap<String,Integer>();
It works fine. I can put some values in it but when I call it in different class it gives me wrong order. For example:
I putted
abc.put("a",1);
abc.put("b",5);
abc.put("c",3);
some time it returns the order (b,a,c) and some time (a,c,b).
What is wrong with it? Is there any step that I am missing when I call this map?
I am trying to proccess a queue of tasks from a database table as fast as possible while also limiting the number of threads to process the tasks.
I am using a fixed sized thread pool with Executors.newFixedThreadPool(N);
I want to know if there is a way of knowing if the thread pool is full, by that I mean are there currently 50 threads running, if so then I'll wait for a thread to be available before starting a new one instead of sleeping the main thread.
Code of what I would like to do:
ExecutorService executor = Executors.newFixedThreadPool(N);
ResultSet results;
while( true ) {
results = getWaitingTasksStmt.executeQuery();
while( results.next() && executor.notFull() ) {
executor.submit( new thread( new runnableInheritedClass(results) ) );
}
}
I have a cookie that is formatted like partA:partB. The colon is not escaped in any fashion. I need to read this cookie in a JSP script, and request.getCookies() is only returning partA. I can't change the cookie because it is used in multiple applications, and fixing the cookie would break production code. Any ideas how I can read the full value of this cookie?
Why is the following syntax correct:
x = y+++y;
(Where it means y++ + y or y + ++y which both mean y * 2 + 1)
But this is not valid syntax:
x = y+++++y;
(Which should mean y++ + ++y, which must mean y and increase y and then add ++y which increases y thus y * 2 + 2)
Is there a reason for this?
Hi, I have some classes and I'm trying to fill the objects of this class. Here is what i've tried. (Question is at the below)
public class Team
{
private String clubName;
private String preName;
private ArrayList<String> branches;
public Team(String clubName, String preName)
{
this.clubName = clubName;
this.preName = preName;
branches = new ArrayList<String>();
}
public Team() {
// TODO Auto-generated constructor stub
}
public String getClubName() { return clubName; }
public String getPreName() { return preName; }
public ArrayList<String> getBranches() { return branches; }
public void setClubName(String clubName) { this.clubName = clubName; }
public void setPreName(String preName) { this.preName = preName; }
public void setBranches(ArrayList<String> branches) { this.branches = branches; }
}
public class Branch
{
private ArrayList<Player> players = new ArrayList<Player>();
String brName;
public Branch() {}
public void setBr(String brName){this.brName = brName;}
public String getBr(){return brName;}
public ArrayList<Player> getPlayers() { return players; }
public void setPlayers(ArrayList<Player> players) { this.players = players; }
}
//TEST CLASS
public class test {
/**
* @param args
* @throws IOException
*/
public static void main(String[] args) throws IOException {
String a,b,c;
String q = "q";
int brCount = 0, tCount = 0;
BufferedReader input = new BufferedReader(new InputStreamReader(System.in));
Team[] teams = new Team[30];
Branch[] myBranch = new Branch[30];
for(int z = 0 ; z <30 ;z++)
{
teams[z] = new Team();
myBranch[z] = new Branch();
}
ArrayList<String> tmp = new ArrayList<String>();
int k = 0;
int secim = Integer.parseInt(input.readLine());
while(secim != 0)
{
if(k!=0)
secim = Integer.parseInt(input.readLine());
k++;
switch(secim)
{
case 1 :
brCount = 0;
a = input.readLine();
teams[tCount].setClubName(a);
b= input.readLine();
teams[tCount].setPreName(b);
c = input.readLine();
while(c.equals(q) == false)
{
if(brCount != 0)
{c = input.readLine();}
if(c.equals(q)== false){
myBranch[brCount].brName = c;
tmp.add(myBranch[brCount].brName);
brCount++;
}
System.out.println(brCount);
}
teams[tCount].setBranches(tmp);
for(int i=0;i<=tCount;i++ ){
System.out.print("a :" + teams[i].getClubName()+ " " + teams[i].getPreName()+ " ");
System.out.println(teams[i].getBranches());}
tCount++;
break;
case 2:
String src = input.readLine();//LATERRRRRRRr
}
}
}
}
The problem is one of my class elements. I have an arraylist as an element of a class.
When i enter:
AAA as preName
BBB as clubName
c
d
e as Branches
Then as a second element
www as preName
GGG as clubName
a
b as branches
The result is coming like:
AAA BBB c,d,e,a,b
GGG www c,d,e,a,b
Which means ArrayList part of the class is putting it on and on. I tried to use clear() method but caused problems. Any ideas.
I´ve been searching for it and I found Encog and Neuroph but I don´t know if any about them... I've to do a final project and I need a litle feedback from humans, sometimes google is not enough XD
Is it a good practice to set stream references to null after closing them? Would this release resources in any way?
Example:
BufferedReader input= new BufferedReader(new FileReader("myfile.txt"));
// code
input.close();
input = null;
// possible more code
Hi. I'm writing an application to analyse a MySQL database, and I need to execute several DMLs simmultaneously; for example:
// In ResultSet rsA: Select * from A;
rsA.beforeFirst();
while (rsA.next()) {
id = rsA.getInt("id");
// Retrieve data from table B: Select * from B where B.Id=" + id;
// Crunch some numbers using the data from B
// Close resultset B
}
I'm declaring an array of data objects, each with its own Connection to the database, which in turn calls several methods for the data analysis. The problem is all threads use the same connection, thus all tasks throw exceptios: "Lock wait timeout exceeded; try restarting transaction"
I believe there is a way to write the code in such a way that any given object has its own connection and executes the required tasks independent from any other object. For example:
DataObject dataObject[0] = new DataObject(id[0]);
DataObject dataObject[1] = new DataObject(id[1]);
DataObject dataObject[2] = new DataObject(id[2]);
...
DataObject dataObject[N] = new DataObject(id[N]);
// The 'DataObject' class has its own connection to the database,
// so each instance of the object should use its own connection.
// It also has a "run" method, which contains all the tasks required.
Executor ex = Executors.newFixedThreadPool(10);
for(i=0;i<=N;i++) {
ex.execute(dataObject[i]);
}
// Here where the problem is: Each instance creates a new connection,
// but every DML from any of the objects is cluttered in just one connection
// (in MySQL command line, "SHOW PROCESSLIST;" throws every connection, and all but
// one are idle).
Can you point me in the right direction?
Thanks
I have about 4 threads. One thread keeps checking some data that the other thread is updating. The others are doing some processing in the background. All have been started at this point.
My question is when the checking thread sees that the data has not been updated yet I currently sleep for a little bit but is there any way for me to tell the system to back to executing the thread that does the updating?
That or is there any way I can put something like a listener on the data(a String) and once its updated an event will fire that will do what it needs to do?
I tried using yield() and it seemed to just keep returning to the thread I called yield() from.
Thanks
public static MySingleton getInstance() {
if (_instance==null) {
synchronized (MySingleton.class) {
_instance = new MySingleton();
}
}
return _instance;
}
1.is there a flaw with the above implementation of the getInstance method?
2.What is the difference between the two implementations.?
public static synchronized MySingleton getInstance() {
if (_instance==null) {
_instance = new MySingleton();
}
return _instance;
}
I have seen a lot of answers on the singleton pattern in stackoverflow but the question I have posted is to know mainly difference of 'synchronize' at method and block level in this particular case.
I'm having some trouble with a hw assignment. In one assignment, we had to create a Person class. Mine was:
public class Person
{
String firstName;
String lastName;
String telephone;
String email;
public Person()
{
firstName = "";
lastName = "";
telephone = "";
email = "";
}
public Person(String firstName)
{
this.firstName = firstName;
}
public Person(String firstName, String lastName, String telephone, String email)
{
this.firstName = firstName;
this.lastName = lastName;
this.telephone = telephone;
this.email = email;
}
public String getFirstName()
{
return firstName;
}
public void setFirstName(String firstName)
{
this.firstName = firstName;
}
public String getLastName()
{
return lastName;
}
public void setLastName(String lastName)
{
this.lastName = lastName;
}
public String getTelephone()
{
return telephone;
}
public void setTelephone(String telephone)
{
this.telephone = telephone;
}
public String getEmail()
{
return email;
}
public void setEmail(String email)
{
this.email = email;
}
public boolean equals(Object otherObject)
{
// a quick test to see if the objects are identical
if (this == otherObject) {
return true;
}
// must return false if the explicit parameter is null
if (otherObject == null) {
return false;
}
if (!(otherObject instanceof Person)) {
return false;
}
Person other = (Person) otherObject;
return firstName.equals(other.firstName) && lastName.equals(other.lastName) &&
telephone.equals(other.telephone) && email.equals(other.email);
}
public int hashCode()
{
return 7 * firstName.hashCode() +
11 * lastName.hashCode() +
13 * telephone.hashCode() +
15 * email.hashCode();
}
public String toString()
{
return getClass().getName() + "[firstName = " + firstName + '\n'
+ "lastName = " + lastName + '\n'
+ "telephone = " + telephone + '\n'
+ "email = " + email + "]";
}
}
Now we have to extend that class and use that class in our constructor. The function protoype is:
public CarLoan(Person client, double vehiclePrice, double downPayment, double salesTax,
double interestRate, CAR_LOAN_TERMS length)
I'm confused on how I use the Person constructor from the superclass. I cannot necessarily do
super(client);
in my constructor which is what the book did with some primitive types in their example. Not sure what the correct thing to do is... Any thoughts? Thanks!
J2EE has ServletRequest.getParameterValues().
On non-EE platforms, URL.getQuery() simply returns a string.
What's the normal way to properly parse the query string in a URL when not on J2EE?
defined variable:
LinkedList list1=new LinkedList();
Object get() in list1 obtains a node of list1
Object remove() in list1 deletes a node of list1
count() is length of list1
for(int i=1;i<list1.count();i++){
if(list1.get(i).startsWith('"',0)) //Error here
list1.remove(i);
}
Error: cannot find symbol
symbol: method charAt(int)
location: class Object
how to fix this problem?
I would like to delete the node in list1 which starts with (").
I am trying to convert my Android app to iOS. This will be my first iOS app. I can't seem to translate this code properly. If someone wouldn't mind showing me how its done, that would be greatly appreciated.
//scrambBase20 is a Byte array
String descramble(String input){
char[] ret;
ret = input.toCharArray();
int offset = -scrambBase20.length;
for(int i=0;i<input.length();i++){
if(i%scrambBase20.length==0)
offset+=scrambBase20.length;
ret[scrambBase20[i%scrambBase20.length]+offset]=(char) ((byte) (input.charAt(i))^0x45);
}
String realRet = "";
for (char x : ret){
realRet+=x;
}
realRet = realRet.trim();
return realRet;
}