FAQ Database Discussion Community


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....

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:...

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...

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...

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...

[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 =...

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...

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...

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...

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....

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...