FAQ Database Discussion Community


Filter duplicates of type Object from List in Java

java,dictionary,filter,duplicates,linkedhashmap
I got a LinkedHashMap that has some duplicates in the output. The map looks like this: Map<Object, List<Object>> myMap= new LinkedHashMap<Object, List<Object>>(); When I sysout this map the result looks like this: Test.example.id = [Source.table1.id, Source.table2.id], Test.example.name = [Source.table1.name, Source.table1.name] Now I'd like to filter out all the duplicates on...

How to retrieve all the values from LinkedHashMap in java while using ResulSet.absolute() method

java,resultset,linkedhashmap
I have to retrieve only some specific rows from the ResultSet ,for that I have absolute() method of ResultSet and have put the values of that row in a LinkedHashMap. But when I execute the code ,only last row is being printed not all the specified rows. The code is:...

Efficient alternative to Map in Java, with regards to autoboxing?

java,android,linkedhashmap,autoboxing,unboxing
I'm using a LinkedHashMap<Integer, Integer> to store values of layers on a tile in a 2D game. Higher numbers are drawn over the lower numbers. In my draw function, I iterate through the value set and draw each one. This means I'm unboxing values (width * height * numLayers) times....

The operator > is undefined for the argument type(s) Object, int

java,collections,linkedhashmap
I am writing a code to find first duplicate character in a string with following code package collectionsExample; import java.util.*; class LinkedHashMap1 { public static void main(String args[]) { String word = "Hare Krishna"; char[] characters = word.toCharArray(); // build HashMap with character and number of times they appear in...

Map put not working Java

hashmap,put,jsonobject,linkedhashmap
I have a Map with some values, and I need to put a new entry into it, the problem is that the put "lost" the Object, and I have only the new Key into it. Here is the code public void addSeries(SerieInterface serieObject) { Map<String, Object> series = this.getSeries(); if...

In memory cache using concurrentHashmap

java,caching,concurrenthashmap,linkedhashmap
6 currently. I am creating a map in my java memory to keep last excessed data. I used concurrenthashmap for the purpose. Use case is as follows: static ConcurrentHashMap<String, Map<Long, Map<String, Object>>> concurrentCache = new ConcurrentHashMap<String, Map<Long, Map<String, Object>>>(); As you see concurrent hash map contains a key n map....

How to populate the dropdown list from sql server database using LinkedHashMap in java

java,sql-server,jstl,html.dropdownlistfor,linkedhashmap
In SQL Server database I have a table which has three columns namely Ref_Name,Ref_from and Ref_to.Now I want a dropdown list to hold values row-wise i.e all column values of the row should be in the dropdown list in following way:- Reference-1(2014-10-10 07:17:00.000 to 2014-10-10 08:46:00.000) Reference-2(2014-09-01 10:00:00.000 to 2014-09-01...

Visualization of TreeMap and LinkedHashMap in Java

java,data-structures,treemap,linkedhashmap
I am trying to understand how these data structures actually are visualized. It is said that TreeMap puts the entries in natural order [of keys] and LinkedHashMap puts entries in the order in which they are inserted. My question is, does the iteration over each of these data structures mean...

Jsoup ArrayList and LinkedHashMap Combo

java,android,arraylist,linkedhashmap
The code I've written uses jsoup to go to a site, views all the paragraph headings, then saves them to an ArrayList called headingList. Here's the tricky part. I've got a map that takes Strings as the keys and ArrayLists as the values. The code is designed in a way...

[GAE - Objectify]: LinkedHashMap doesn't respect key's order

google-app-engine,objectify,linkedhashmap
I'm working with Objectify to access DataStore in a Google App Engine application. I have 2 Entities: @Entity public class Client { @Id String id; } @Entity public class Queue { @Index @Id String name; @Load LinkedHashMap<String,Ref<Client>> clientsInQueue; } In a transaction, i do something like this: Client newClient =...

Add Elements to ArrayList that is inside LinkedHashMap [Android]

java,android,arraylist,linkedhashmap
I have a list of Users, each with a list of their Groups. Something like this: John -->[GroupA] Peter --> [GroupB, GroupC] Bob --> [GroupC] Tom --> [GroupA,GroupB] Jack --> [] Then I have my own list of groups: Me -->[GroupA, GroupB, GroupC]. So what I want is to put...

LinkedHashMap vs ArrayList with Bluetooth Scanning and ListView

java,listview,arraylist,linkedhashmap
I have a little bit of a confusion when it comes to what is considered the better implementation. One the one hand, LinkedHashMap provides the following benefits: Prevents duplicate items (I need to be able to prevent a scanned Bluetooth device to not repeatedly enter the list.) Provides easy access...