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I think it can be deleted. We can't check the special case where T is U. Thanks for the great work guys, and keep going ;) Cheers, /Benoit 👍 1 JΛVΛSLΛNG member danieldietrich commented Mar 24, 2016 Hi @benoitheinrich, the existing comparator is related to elements Seems to me a straightforward question. Source

For example:

 String foo = "bar"; 
Yishagerew lulie There are actually various ways to implement a comparator inside a class without implementing the comparator interface, here is one.
JΛVΛSLΛNG member danieldietrich commented Mar 24, 2016 Thank you @benoitheinrich, you are right. If no comparator is specified, we could chose a new comparator unordered. Remeber i already 99% done with the homework so you are not helping me cheating or something beside it's just a homework for SelfLearning. http://stackoverflow.com/questions/15943031/why-does-treeset-throws-classcastexception

Treeset Comparable Example

Can proliferate be applied to loyalty counters? Especially compare(o1, o2) == -1 == compare(o2, o1) in the unordered case. Regards. Who knows what this part of the catch block was supposed to be doing?

What causes this weird behaviour?3Which data structure should I use to support key-value mappings, reverse iteration and insertion ordering? I've read I need a Comparator or to implement Comparable but I don't know how to do that, and I think there might be a simpler solution (although perhaps not as extends T2, ? Treeset Example In Java It can also occur when creating empty collections without specifying a Comparator.

You need to download fresh complete dev builds to avoid untested combinations. asked 3 years ago viewed 13680 times active 3 years ago Upcoming Events 2016 Community Moderator Election ends Nov 22 Visit Chat Linked 0 ClassCastException with Java's TreeMap when using custom p = (PatientImpl) p; Boolean equal = false; //make sure p is a patient before we even compare anything if (p instanceof Patient) { Patient temp = (Patient) p; if (this.firstName.equalsIgnoreCase(temp.getFirstName())) package test; import java.util.Arrays; import java.util.SortedSet; import java.util.TreeSet; import java.util.function.BiConsumer; import java.util.function.BinaryOperator; import java.util.function.Function; import java.util.function.Supplier; import java.util.stream.Collector; public class JavaSortedSetTest { public static void main(String[] args) { SortedSet sortedSet =

public class ComparatorTest { @org.junit.Test public void compare() throws Exception { java.util.Comparator wonkyComparator = new Comparator(); // ints assertEquals(Integer.compare(5, 9), wonkyComparator.compare(5, 9)); // anon objects Object a = new Object(){ int Arraylist Is Ordered While Hashset Is Not Java's int is 32 bit, our machines address 64 bit memory. up vote 4 down vote favorite I have several arrays in the form: private static String[] patientNames = { "John Lennon", "Paul McCartney", "George Harrison", "Ringo Starr" }; Then I make You may also like ...

Java Lang Classcastexception Cannot Be Cast To Java Lang Comparable Treemap

Hot Network Questions How to handle swear words in quote / transcription? http://www.programcreek.com/2009/02/implement-comparable-for-a-treeset/ Actually, the latter would have given a compiler error since Java 5.0, but before it would have given the error. Treeset Comparable Example While they would prevent the exceptions @ruslansennov pointed out, the idea has a major flaw where if Comparable were declared at the interface or abstract class then you could end up Cannot Be Cast To Java.lang.comparable Java How can I accurately cross-cut a board that is too wide for my table saw?

danieldietrich added the design/refactoring label Mar 24, 2016 danieldietrich added this to the 2.1.0 milestone Mar 24, 2016 JΛVΛSLΛNG member danieldietrich commented Mar 24, 2016 Task: Create singleton javaslang.collection.Comparator.NoOrderComparator (see also asked 6 years ago viewed 21558 times active 3 years ago Upcoming Events 2016 Community Moderator Election ends Nov 22 Visit Chat Linked 617 What issues should be considered when overriding Polywhirl Mar 2 '14 at 3:13 The TreeSet relies on your Patient/PatientImpl equals/hashCode/compareTo methods. On the scala side, their SortedSet.flatMap returns either a Set or TreeSet depending on what you map to. Treeset Comparator Duplicates

  1. Browse other questions tagged java collections treemap or ask your own question.
  2. Perhaps something like what @benoitheinrich proposed, but with additional constraints where in a.compareTo(b) b must be an instance of a.getClass().
  3. Was it legal to rant against trick or treating via loudspeaker during halloween?
  4. like this: O------------------------ / \ T extends Comparable T' / \ / \ T1 T2 T3 T4 Example: Set set = Set.of(t1, t2, t3, t4); where t1 of type T1, t2
  5. N.
  6. more stack exchange communities company blog Stack Exchange Inbox Reputation and Badges sign up log in tour help Tour Start here for a quick overview of the site Help Center Detailed
  7. I think in practice it will be a rare case.

In the cod i am working on i would like MyOwnClass to be compared to the string properties so how can i do it? extends R> mapper); @Override SortedSet> zipAll(Iterablehave a peek here Employee cannot be cast to java.lang.Comparable is the problem.

JΛVΛSLΛNG member ruslansennov commented Mar 24, 2016 Do you think this could work? Java Implement Comparable So, again, this bug is not related to OSGi, and MM seems not to be the source for OSGi problems: The problems seem to be caused by dependency checking in AU Join them; it only takes a minute: Sign up Why does TreeSet throws ClassCastException up vote 6 down vote favorite 2 In below code I am trying to add two employee

Join them; it only takes a minute: Sign up Why does my TreeSet not add anything beyond the first element?

You said you implement compareTo from the Comparable interface, but in your comment you say that you didn't, so am I correct in assuming that you just return 0; in the Just ran into this exact same issue and agree with most of what's been said here. The type comparison is fast and we may safe a second equals check, which may be cost-intensive. How Treeset Works Internally In Java LinkedHashSet A simple TreeSet example Comparable vs.

The contract requires that: sgn(x.compareTo(y)) == -sgn(y.compareTo(x)) it's transitive: x.compareTo(y)>0 && y.compareTo(z)>0 implies x.compareTo(z)>0 x.compareTo(y)==0 implies that sgn(x.compareTo(z)) == sgn(y.compareTo(z)) for all z Additionally, it recommends that: (x.compareTo(y)==0) == (x.equals(y)), i.e. So what do you think the problem is? that was really quick ;) In fact your right, I was doing another test scenario to check how that new comparator would work and indeed, it applies to the mapped type Check This Out TreeSet is only appropriate if you need the Set sorted, either by the Object's implementation of Comparable or by a custom Comparator passed to the TreeSet's constructor.

posted 6 years ago The TreeSet orders it's elements. Does calling a function that mutates static local variables twice in the same expression lead to undefined behavior? Set s = new TreeSet(); s.add(new Employee(1001)); Or Set s = new HashSet(); s.add(new Employee(1001)); s.add(new Employee(1002)); Then result is success there is no exception. You > need to download fresh complete dev builds to avoid untested combinations. > Otherwise you are on your own: you can expect sundry exceptions and need to be > evaluating

Browse other questions tagged java set treeset or ask your own question. Perhaps my story / rant is a bit over complex for this discussion. Do you think this could work? can you give me an example Please.

Does Intel sell CPUs in ribbons? Remember, TreeMap implements SortedSet, so it has to know how to order the elements one way or another. You can add only one element into TreeSet which does not implement Comparable because it does not need to be compared with other elements. share|improve this answer answered Sep 23 '15 at 1:35 Flavio H.

The static factory methods, e.g. Lam, 2013ISBN0992023300, 9780992023300Length716 pagesSubjectsComputers›Programming›Object OrientedComputers / Programming / GeneralComputers / Programming / Object Oriented  Export CitationBiBTeXEndNoteRefManAbout Google Books - Privacy Policy - TermsofService - Blog - Information for Publishers - Report an The mind is a strange and wonderful thing. Join them; it only takes a minute: Sign up List to TreeSet conversion produces: “java.lang.ClassCastException: MyClass cannot be cast to java.lang.Comparable” up vote 11 down vote favorite 2 List myclassList =

posted 7 years ago Depends--how do you want MyOwnClass to be compared to other instances?