Why do I get compiler errors with this Java code?
1 public List<? extends Foo> getFoos()
2 {
3 List<? extends Foo> foos = new ArrayList<? extends Foo>();
4 ...
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private ArrayList<String> colors = new ArrayList<String>();
Looking at the example above, it seems the main point of generics is to enforce type on a collection. So, instead of having an array of ... |
I am getting confused as and when i come across a generic method of this sort?
public static <T> T addAndReturn(T element, Collection<T> collection){
collection.add(element);
return ...
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Given a List of POJO's, if I serialize them with XStream I get:
<list>
<pojo>
<a>a</a>
<b>b</b>
</pojo>
<pojo>
...
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I have a collection of elements of type B and C, which all extends A. I need to filter the collection to get elements of only B type.
Is there any ... |
How can I create a Set in java, and then add objects to it when it is constructed. I want to do something like:
testCollision(getObject(), new HashSet<MazeState>(){add(thing);});
But that doesn't seem quite right.
... |
I have the following kind of situation:
Set<Element> set = getSetFromSomewhere();
if (set.size() == 1) {
// return the only element
} else {
throw new Exception("Something is ...
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I am wondering how to add a specialized object to a generic collection
I am using the following code
Collection<T> c;
Class1 object1 = new Class1()
c.add((T)object1)
Is this the correct way?
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Is there a standard idiom for getting a set of each unique pair of elements in a given Collection?
For our purposes, the set of (a,b) is equivalent to (b,a), ... |
Hello Friends IS there any collections available in jakarta commons or in java sdk which will help me do validation as we enter values into it. I am looking to store account no/sortcode in a collection and if are trying to insert the same accountno/sortcode combination again i should get validation errors. Wer can have duplicate sortcodes but account numbers is ... |
Modifiying collection elements (Java in General forum at JavaRanch) A friendly place for programming greenhorns! Register / Login Java Forums Java Java in General Modifiying collection elements Post by: Nicholas Jordan, Ranch Hand on Jul 01, 2007 18:27:00 When originally concepting my main class, I wrote data items to a file as a means of passing collections of data ... |
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Orederid Offerid offername OfferTotal productId productName productTerm ProductDesc 1 1 Biz1 10 11 landline 1 landline 1 1 Biz1 10 22 wireless 3 wireless 1 1 Biz1 10 33 cellphone 4 cellphone 1 2 Biz2 15 44 TV 3 TV 1 2 Biz2 15 77 Cable connection 2 Cable connection 1 2 Biz2 15 22 wireless 1 wireless 1 3 Biz3 ... |
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What about a while loop? While its true it will continue going through your code, if the boolean ever becomes false or if you reach the end of your array list using an iterator you can insert a break statement. Then check outside of the loop if your boolean is true, and if it is then run code00. I'm a bit ... |
Greetings knowledgeable Java people. I've hit a wall again, and I'm afraid I'll sink deeper into your debts. please consider with me, the following collection. Let's say it is of type ArrayList (I don't think it matters too much what type of collection it is). What would be the best approach to take if I wanted to check the ArrayList and ... |
I wouldn't use an iterator in this scenario. I would use a for loop because you are probably going to throw a ConcurrentModificationException or just have bad results if your trying to add things while iterating. Also, consider a different approach to the problem like using a Queue and polling from that. |
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