I'm getting a compiler error for this line: Collections.sort(terms, new QuerySorter_TFmaxIDF(myInteger)); My customized Comparator is pretty basic; here's the signature and constructor: public class QuerySorter_TFmaxIDF implements Comparator<Term>{ private int numberOfDocs; QuerySorter_TFmaxIDF(int n){ super(); numberOfDocs ...
Possible Duplicate: C++ struct sorting Is it possible to sort a vector in C++ according to a specified sorting method, like used in Java's Collections.sort that takes a Comparator? ...
public class PriorityQueue<T> { private PriorityNode<T> head, tail; private int numItems; public PriorityQueue(){ numItems = 0; head=null; tail=null; } public void add(int priority, T value){ PriorityNode<T> newNode = new PriorityNode<T>(priority,value); if(numItems == 0){ head = newNode; tail = n...
I want to create a TreeMap in Java with a custom sort order. The sorted keys which are string need to be sorted according to the second character. The values are also string. Sample map: Za,FOO Ab,Bar ...
I would like to sort alphanumeric strings the way a human being would sort them. I.e., "A2" comes before "A10", and "a" certainly comes before "Z"! Is there any way to do with without writing a mini-parser? Ideally it would also put "A1B1" before "A1B10". I see the question "Natural (human alpha-numeric) sort in Microsoft SQL 2005" with ...
Hello World!! :D I had a question which is pretty easy if you know the answer I guess. I read about sorting ArrayLists using a Comparator but somehow in all of the examples people used compareTo which according to some research is a method working on Strings... I wanted to sort an ArrayList of custom objects by one of their properties:...
I would like to compare lists of elements of a given type, to see which list is "bigger". new BuiltInComparer<IEnumerable<int>>().Compare( new[] {3,2,3}, new[] {1,2,3}) ...would return 1 new BuiltInComparer<IEnumerable<int>>().Compare( new[] {1,2,3}, new[] {1,2,4}) ...would return -1 etc Is there any such built i...
I learned how to use the comparable but I'm having difficulty with the Comparator. I am having a error in my code: Exception in thread "main" java.lang.ClassCastException: New.People cannot be cast to java.lang.Comparable at java.util.Arrays.mergeSort(Unknown Source) at java.util.Arrays.sort(Unknown Source) at java.util.Collections....
I've tried this a couple ways, the first is have a class that implements comparator at the bottom of the following code. When I try to pass the comparat in sortListByLastName, I get a constructor not found error and I am not sure why import java.util.*; public class OrganizeThis implements WhoDoneIt { /** Add a person to the ...
Comparable contract specifies that e.compareTo(null) must throw NullPointerException. From the API: Note that null is not an instance of any class, and e.compareTo(null) should throw a NullPointerException even though e.equals(null) returns false. On the other hand, Comparator API mentions nothing about what needs to happen when c...
If I create a single instance of a Comparator, can that instance be used across multiple threads to sort collections using Collections.sort()? Or, do I need to create a new instance of the Comparator for each call to Collections.sort() to ensure thread safety? ...
If I have a list of elements I would like to sort, Java offers two ways to go about this. For example, lets say I have a list of Movie objects and I’d like to sort them by title. One way I could do this is by calling the one-argument version of the static java.util.Collections.sort( ) method with my movie list as the single argument....
How to right this syntax correctly: if (tipoTropaPrioritaria[m] || troopsCount[m] || availableTroops[m]) == ("null" || "undefined") { ... } (to check if any of the first 3 variables is null or undefined) ...
I have a method which needs a Comparator for one of its parameters. I would like to pass a Comparator which does a normal comparison and a reverse comparator which does in reverse. java.util.Collections provides a reverseOrder() this is good for the reverse comparison, but I could not find any normal Comparator. The only solution what ...
Hi stack overflow. I need to insert some objects contained in a Node class into a LinkedList class in a sorted over. The Node class looks like: public class Node { private Card val; private Node next; public Node(Card v) { val = v; next = null; } where card implements the Comparator interface. I'm trying to...
Hi, I want an open source/free tool which can test the schema, data, user defined functions, views and stored procedures between two different databases or two different versions of the databases. I am using MySQL database. Currently I am using DB Solo which is a 30 day trail version. Thanks in advance. ...
I've written a custom comparator to compare my node classes, but the java priority queue is not returning my items in the correct order. Here is my comparator: public int compare(Node n1, Node n2){ if (n1.getF() > n2.getF()){ return +1; } else if (n1.getF() < n2.getF()){ return -1; } else { // equa...
Hello, everyone! As far as I know, things such as SortedMap or SortedSet, use compareTo (rather than equals) on Comparable<?> types for checking equality (contains, containsKey). But what if certain types are equatable by concept, but not comparable? (Hash codes, memory addresses, ...) I have to declare a Comparator<?> and override th...
Hi, I have a table called _sample_table_delme_data_files which contains some duplicates. I want to copy its records, without duplicates, into data_files: INSERT INTO data_files (SELECT distinct * FROM _sample_table_delme_data_files); ERROR: could not identify an ordering operator for type box3d HINT: Use an explicit ordering operator...
I need a comparator as part of a strategy pattern that can either use the natural ordering of the objects or some custom ordering. For the natural ordering case, I wrote a simple comparator: private static class NaturalComparator<T extends Comparable<? super T>> implements Comparator<T> { @Override public int compare(T o1, T o2)...