Develop Reference

Finding duplicates in an ArrayList(JFrame)

I'm trying to do a swing application which adds names to an ArrayList and then displays it in Jcombobox.I already did the window and everything but I can't seem to get the hang off detecting duplicate names.
I tried
btnnext.addActionListener(new ActionListener() {
Override
public void actionPerformed(ActionEvent e) {
if(checkDuplicate(names)==true)
{
names.add(txtname.getText());
txtname.setText("");
}
else {
JOptionPane.showMessageDialog(null,"DUPLICATE! do not add");
}
}
});
public static boolean checkDuplicate(ArrayList<String> list) {
HashSet set = new HashSet();
for (int i = 0; i < list.size(); i++) {
boolean val = set.add(list.get(i));
if (val == false) {
return val;
}
}
return true;
}
It only says that I have duplicate when I already add it to the ArrayList and when I get the message I can't add anything else.
input example:
test
test
and then it stops accepting new Strings and only displays the message DUPLICATE! do not add

As I said in my comment:
This happens because you are basically creating a Set view of your ArrayList every time you call checkDuplicate rather than comparing the item you're trying to add with the existing list. In other words your checkDuplicate is written such that it only returns true when a duplicate already exists within the list. You need to compare the new item with the list instead. Step through your logic carefully either with a debugger or by manually writing down the values of your variables and you will see the problem.
You could simply change this line:
if(checkDuplicate(names)==true)
to this:
if(!names.contains(txtname.getText()))
You don't really need checkDuplicate since it's "reinventing the wheel" so to speak. ArrayList already provides a contains method that you can use to your advantage.

Java adding an ArrayList to Existing Object

I'm having some trouble with one of my methods. A brief overview of what my method is supposed to do. Here's what I have so far.
public boolean addGame(String team1, String team2) {
boolean result;
if (team1.equals(team2))
result = false;
}
if (a game between two parameter teams has previously been added by
earlier call to addGame){
result = false;
}
else {
result = true;
}
I want my method to return false if a game between two parameter teams has previously been added to the conference object by an earlier call to addGame and
if the name of team1 and team2 are the same name.
My issue is the syntax for what's inside of my second if statement. Not sure how to go about it.
Thanks in advance for all the help.

Depends on how long you plan on saving the information. If it is just in the runtime, you can do something such as saving the two teams to an array.
If you want to save it for a longer time, you need some way of persisting the information, possibly a table in a database?
Then, you can query to data and check if the combination existed already.

You can create a history of the added teams:
ArrayList<String> history = new ArrayList<String>();
//As you add the teams
history.add(teamName); //add to history as well
//To check if teams already exist or added before
if(history.contains(team1) || history.contains(team2)){
return false;
}

If you have an ArrayList called games, and the games are stored in the format "team1;team2", then you can do games.indexOf(team1 + ";" + team2) == -1 for the if statement.

How to compare group of Strings

I have the following code..
WorkPackage spack=(WorkPackage)primaryBusinessObject;
WTSet res;
WTPart spart=null;
String state=null;
res=wt.facade.persistedcollection.PersistedCollectionHelper.service.getAllMembers(spack);
System.out.println("the values are "+res);
java.util.Iterator iter=res.persistableIterator();
while(iter.hasNext())
{
spart=(wt.part.WTPart) iter.next();
wt.lifecycle.LifeCycleState st=spart.getState();
String state=st.toString(); //Lifecycle state of part object
}
if(state.contains("APPROVED"))
result="Proceed";
In the above code I'm passing a windchill package and it may have muliple number of WTPart objects.Each part may have different life cycle states.What I want is if every part state is "APPROVED" means it should proceed in my workflow.
For eg.
LifeCycle states of
Part1=IN WORK
Part2=IN REVIEW
Part3=APPROVED
Part4=APPROVED
Part5=CANCELED
I want to compare all the objects from my package is APPROVED I can store these in vector or a arraylist and I don't know how to compare all the objects from that.My above code will pass if any one of objects state is APPROVED.I know this question not related to windchill.Somebody help me out of it

If you store all of the states in an ArrayList<String> states then you can test if they are all APPROVED using something like:
boolean allApproved = true;
for(int i = 0; i < states.size(); i++) {
if(!states.get(i).equals("APPROVED") {
allApproved = false;
}
}
At the end of the for loop, if allApproved is still true, you're good to go.

Advice on Java program

My java project required that I create an array of objects(items), populate the array of items, and then create a main method that asks a user to enter the item code which spits back the corresponding item.
It took me a while to figure out, but I ended up "cheating" by using a public variable to avoid passing/referencing the object between classes.
Please help me properly pass the object back.
This is the class with most of my methods including insert and the find method.
public class Catalog {
private Item[] itemlist;
private int size;
private int nextInsert;
public Item queriedItem;
public Catalog (int max) {
itemlist = new Item[max];
size = 0;
}
public void insert (Item item) {
itemlist[nextInsert] = item;
++nextInsert;
++size;
}
public Item find (int key) {
queriedItem = null;
for (int posn = 0; posn < size; ++posn) {
if (itemlist[posn].getKey() == key) queriedItem = itemlist[posn];
}{
return queriedItem;
}
}
}
This is my main class:
import java.util.*;
public class Program {
public static void main (String[] args) {
Scanner kbd = new Scanner (System.in);
Catalog store;
int key = 1;
store = new Catalog (8);
store.insert(new Item(10, "food", 2.00));
store.insert(new Item(20, "drink", 1.00));
while (key != 0) {
System.out.printf("Item number (0 to quit) ?%n");
key = kbd.nextInt();
if (key == 0) {
System.out.printf("Exiting program now!");
System.exit(0);
}
store.find(key);
if (store.queriedItem != null) {
store.queriedItem.print();
}
else System.out.printf("No Item found for %d%n", key);
}
}
}
Thanks I appreciate the help!!!!!!

store.find(key); returns an Item you should use it and delete the public field from Catalog
public Item find (int key) {
Item queriedItem = null;
//....
}
Item searched = store.find(key);
if (searched != null)
searched.print();
else
System.out.printf("No Item found for %d%n", key);

Remove your use of queriedItem entirely and just return the item from find: Replace
store.find(key);
if (store.queriedItem != null){store.queriedItem.print();}else System.out.printf("No Item found for %d%n", key);
With
Item foundItem = store.find(key);
if (foundItem != null) {
foundItem.print();
} else System.out.printf("No Item found for %d%n", key);

Well, here are some suggesetions (choose complexity at your own discretion, but all of them is highly recommended):
Research Properties, for example here. Or XML. You could populate the array with values from a configuration file for greater flexibility.
Use constanst for literals in your code (where they are necessary).
Create an ApplicationFactory the initializes the whole application for you. Things like this need to be separated from your domain logic.
Create a UserInputProvider interface so you can easily change the way the input of the user is read without affecting anything else. Implement it with a ConsoleInputProvider class for example.
In general, try using interfaces for everything that's not a pure domain object (here, the only one you have is probably Item).
Try to keep your methods as short as possible. Instead of doing many things in a method, have it invoke other methods (grouping related logic) named appropriately to tell what it is doing.
If you're not allowed to cheat and use List or a Map, devise your own implementation of one, separating data structure and handling from the logic represented by Catalog (i.e. Catalog in turn will delegate to, for example, Map.get or equivalent method of your data structure implementation)
Your main should basically just have ApplicationFactory (or an IoC framework) to build and initialize your application, invoke the UserInputProvider (it should not know the exact implementation it is using) to get user input, validate and convert the data as required, invoke Catalog to find the appropriate Item and then (similarly to the input interface) send the result (the exact data it got, not some string or alike) to some implementation of a SearchResultView interface that decides how to display this result (in this case it will be a console-based implementation, that prints a string representing the Item it got).
Generally, the higher the level of decoupling you can achieve, the better your program will be.
The Single Responsibility Principle states: " every class should have a single responsibility, and that responsibility should be entirely encapsulated by the class". This is also true for methods: they should have one and only one well defined task without any side effects.

Skip a record in LoadFunc.getNext()

I'm extending the LoadFunc. In the getNext function I'd like to skip returning a tuple under certain conditions - this way I could only load a sample of the data file. I tried returning null for the rows I don't want to return but the problem is that the method terminates after the first null Tuple is returned.
Does anyone know of a way to do this? Should I do it in a different method?
Thanks in advance.

(Assuming you mean LoadFunc in Pig ... )
I would suggest writing a new method that does what you want simply to not break the original documented use of the getNext() method.
You should look at the source for the Pig classes that extend LoadFunc and see how they implement getNext(). For example: TextLoader
From there it should be fairly trivial to do what you're trying to do.
Edit to try and offer a little more detailed help:
(This is using the TextReader as an example)
The getNext() method is reading from a RecordReader. It does this by calling RecordReader.nextKeyValue() to advance to the next record. You check to see if that's true (meaning it read a record) and if it is, you call RecordReader.getCurrentValue() to retrieve the value.
Lets say you only wanted every fifth one as a sample in getNext():
int count = 0;
Text myText = null;
whlie(myRecordReader.nextKeyValue() == true)
{
if (count == 4)
{
myText = (Text) myRecordReader.getCurrentValue();
break;
}
count++;
}
if (myText != null) // we didn't hit the end; we have a record
{
... // create the tuple
return myTuple;
}
else
return null;
(corrected my silly off-by-one mistake)