How To Get Method Of HashMap Or Hashtable
Jul 25, 2014How get method of HashMap or Hashtable works internally in Java can any body let me know how does it work..
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HashTable Remove Method Using Arrays
Nov 1, 2014I'm writing the remove method, where you insert the key and it searches the key, if the key is found you remove the value inside the table and return that value, if they key is not found you return null. I did this method but is not returning anything in the main so I try to print inside an if to see if it was entering the condition and it appears to be looping, I'm using arrays because its an assignment
public V remove(K k) {
int key = funcionHash(k);
V key2 = (V) tabla[key].value;
int intento=1;
if(this.estatus[key]==1){
while(intento<this.tabla.length/2){
if(this.tabla[key].key.equals(k)){
[Code] ....
Which Two Method HashMap Key Object Should Implement
Jul 25, 2014Which two method HashMap key object should implement?..
View Replies View RelatedHow To Traverse Through Hashtable
Mar 12, 2014I was wondering how to traverse through a hashtable. I am stuck on how to implement an iterator for the values of some hashtable.
Java Code:
public Iterator<V> values() {
return new Iterator<V>(){
@Override
public boolean hasNext() {
// TODO Auto-generated method stub
return false;
[Code] ....
NullPointerException With Hashtable Object
Mar 1, 2014I am having some problems with some code and I need an extra set of eyes. It appears I've missed something. I am getting a NullPointerException with a Hashtable object, which I can clearly see I've created. So I'm not quite sure why it is happening. I am pretty sure it is do with the code I've posted because I've tested everything else involved.Here is the code where it happens,
Java Code:
public void siteGen(String user, String site)
throws ExcGenDatabad, ExcSiteNodomain, Exception {
System.out.println("calling siteGen, user: " + user + ", site: " + site);
String nginx_template;
String fpm_template;
[code]....
Hashtable Counting Words
Jan 1, 2015I was browsing around and I found a question asking to find how many times a word occurred in a sentence. I am using a hashtable, over kill yes but I need to use them more. However my counter is not working, not really sure why.You can see in the main method I have two repeating names but it returns 0.
package frequency;
import java.util.Hashtable;
public class CheckFrequency {
hashtable<String, Word> words = new Hashtable<String, Word>();
[code]....
HashTable Insertion - Duplicate Records
Apr 20, 2015I am having some difficulty adding a new item to the HashTable when a collision occurs. We can only use the basic utilities to code this, so we are coding a HashTable by hand. We have an array of length of 10, which each index holds or will hold a Node for a Linked List.
The code hashes fine, adds the item, but the problem exists when adding items that already been hashed. The project is much bigger, but this is the engine behind the rest, and I figured I would tackle this first.
The items we are adding are objects which are states containing different information, we hash based on the ASCII sum % tableSize.
Here is the code I am testing with to add items:
HashTable ht = new HashTable(10);
State az = new State("Arizona","AZ","W",2,"Y",2);
State fl = new State("Florida", "FL", "F", 2, "X", 2);
State hi = new State("Hawaii", "HI", "H", 3, "Z", 1);
State al = new State("Alabama", "AL", "A", 5, "W", 0);
ht.insert(hi);
[Code] ....
Double Hashing For Inserting Integer Into Hashtable?
Apr 29, 2014I'm having a problem implementing double hashing when I insert a value into the table i get this for the output:
Insert []. Is there something I'm doing wrong? I'm not getting any errors
public static int size = 0;
public static ArrayList<Integer>[] a;
public static void interactiveMode(Scanner input) {
int menuChoice = 0;
do {
System.out.println("
Interactive Mode:");
[code]....
Implement Separate-chaining Hashtable From Scratch?
Mar 19, 2014I need to implement a separate-chaining hash table from scratch and I don't need to know the code or anything I would just like an explanation of how I would go about doing the algorithm for this perhaps pseudocode and then I can figure out the rest.
View Replies View RelatedDouble Hashing For Inserting Integer Into Hashtable
Apr 26, 2014I'm having a problem with double hashing, its supposed to have the user insert an integer into the table and the integer is hashed into the table by the mod of the size of the table so say for instance table size 10 I insert 89 that inserts into 9 because 89%10=9 then i insert 18 that goes into 8 but then once i insert 69 its supposed to collide with index 9 and then uses 7-(69%7) for prime number double hashing...but it just goes into index 9 instead so in 9 it puts 89,69...there's no errors just the wrong output
System.out.print("Enter size of table: ");
int n = input.nextInt();
size=n;
a = new ArrayList[size];
for (int i = 0; i < size; i++) {
a[i] = new ArrayList<Integer>();
[code]....
Buffered Image - Color Palette Hashtable
Feb 12, 2014How can I write a BufferredImage to an 8-bit .bmp using indexed colors stored in a <String,Color> Hashtable?
I've never used Hashtables before, and I didn't know color indexing existed until now, but I can do most other things in java fairly well.
I'm not looking for code, just the concept, as I really don't know how Hashtables work (although I could figure it out), and how color indexing does. I know how to write image files, just not indexed or with a specific number of bits. I am using Hashtables generated from GIMP.
EDIT: I mainly want to know how to save a BufferedImage as an indexed .bmp.
Accessing ArrayList Elements (Integer / String) And Put Them Into Hashtable
Mar 4, 2014I have a data structure such as: ArrayList<ArrayList<Integer,String>
The data looks as [[1,2,3] [3,4] [99,98,40,32,45,65,1]]
I am trying to access each element and put them into a hashtable such as:
Hashtable<Integer,String>
With what I am doing below I am getting an out of bound error but can't see any other way of accessing the element
public static void hash(ArrayList<ArrayList<String>> list)
{
for(int i = 0; i < list.size(); i++)
{
int cnt = 0;
for(int y = 0; y < list.size(); y++)
{
if (! hashMap.containsValue(list.get(i).get(y)))
{
hashMap.put(cnt, list.get(i).get(y));
cnt++;
}
...
JSP :: Generate Hashtable And Display Its Key Value Pairs Back To Browser - How To Prevent Timeout
Jun 24, 2004I have a jsp page that generate a hashtable and display its key-value pairs back to the browser. The problem is that it takes on an average about 15 minutes to build this hashtable, and as a result, I always get a timeout error. What can I do to avoid getting the timeout error without changing the server configuration for timeout
View Replies View RelatedHow To Get Value For Key In Hashmap
Sep 26, 2014In my code I read in a file of states and statecapitals then store them into a hashmap. I then ask the user what the capital is for the random state displayed.The problem I am having is getting the value for the random generated state. When I enter the correct capital for the state, it is still being marked incorrect. Here is my code.
Java Code: try {
Scanner scanner = new Scanner(file);
String[] values;
[code]....
Add Key-Value Of One HashMap As Value In Another HashMAp
Jul 30, 2014I have two Hasmaps as
Map<String,String> componentValueMap = new HashMap<String,String>();
Map<String,Map<String,String>> componentNameValueMap = new HashMap<String,Map<String,String>>();
I have for loop which are getting values from XML
XML structure as
<Raj>
<user>raj</user>
<password>123</password>
</Raj>
<Dazy>
<user>dazy</user>
<password>123</password>
</Dazy>
Now during first loop it will put user and password in map and after that put map refernce in another map. Same procedure for another values. But during iterating componentNameValueMap , i am getting Raj, Dazy as Key but not getting different values for them. I am getting latest values of Dazy in both Keys.
Because put method of Map<String,String> componentValueMap is replacing values. But I don't to replace them and want to get different values for different keys.
Getting Object From HashMap
Oct 23, 2014I am trying to retrieve a object from a hashMap not I am not sure what is wrong. I am trying to calculate if a car was speeding. They're 5 cameras and as they pass each camera I can calculate the speed. They key is camera number and I am sending in a Vehicle object.
Now I am trying to retrieve variables from the Vehicle so I can do the calculations. I am getting the error in the loop in void calculateSpeeding(). The loop is only for testing at the moment.
package online.practice.averageSpeed;
import java.util.Arrays;
import java.util.HashMap;
public class Vehicle {
String licensePlates;
[Code] ....
Printing A Key And A Value From HashMap
Mar 28, 2014I have a hashmap of the form HashMap <String, Set<String>>I am trying to create a method with one argument. The argument is a key for the hashmap, if it exists it should print out the key and the associated values. I'm falling over at even getting it to print the key, it keeps printing all the keys from within the hashmap as I don't know how to load the argument into it. I have this so far
Java Code:
public void printValue(String club)
{
boolean result = clubMap.containsKey(club);
if (result)
{
String key = clubMap.keySet(club).toString();
System.out.println(key );
[code]....
How To Find Particular Objects In HashMap
Dec 25, 2014Suppose i have a hashMap which includes instances of class Employees and instances of class Customers.
How can i get the employees objects only?
And would it be possible to find the oldest staff by comparing the ages stored in the age fields of the staff objects.
HashMap / How To Get Size Of Value And NOT The Keys
Apr 5, 2014I am asked in my assignment to make a program that accepts a text file as an example a novel and i have to sort each word as a PERSON or ORGANIZATION or LOCATION or O as in Other , example :
Microsoft/ORGANIZATION ,/O Nelly/PERSON !/O '/O
Now we notice that microsoft is and organitzation and "," is Other and Nelly is a person's name and so on ..
Now I am asked to return the numbers of tags in the text which is 4 in our case because we have (ORGANIZATION,PERSON,LOCATION,OTHER)
My question here is my logic true ? And since i made a map of String,String ; Is there any way that i can get the size of the values in our case the values are the organization etc.. ?
import java.io.File;
import java.io.FileNotFoundException;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
[code].....
Getting Keys From Values In Hashmap
Feb 9, 2014I have one doubt.In HashMap if keys contains 1,2,3,4 and values are a,b,c,d we can get values using get(key) method like 1 will A,2 will return B and so on. Can we get the keys from values like A will get 1 and also if in key if there is a String like 1,2,3,Z and value is A,B,C,7 Z should get me 7. Here I am not using any generics.
View Replies View RelatedHashmap Slower After Deserialization?
Feb 15, 2015I have a pretty large Hashmap (~250MB). Creating it takes about 50-55 seconds, so I decided to serialize it and save it to a file. Reading from the file takes about 16-17 seconds now.
The only problem is that lookups seems to be slower this way. I always thought that the hashmap is read from the file into the memory, so the performance should be the same compared to the case when I create the hashmap myself, right? Here is the code I am using to read the hashmap into a file:
File file = new File("omaha.ser");
FileInputStream f = new FileInputStream(file);
ObjectInputStream s = new ObjectInputStream(new BufferedInputStream(f));
omahaMap = (HashMap<Long, Integer>) s.readObject();
s.close();
300 million lookups take about 3.1 seconds when I create the hashmap myself, and about 8.5 seconds when I read the hashmap from file.
Removing A Key From Hasmap Within Hashmap
Dec 1, 2014SO my current code creates a graph with vertices and weighted edges. This data is stored in a hashmap. The key of the hashmap is the vertex and the value is a second hashmap. This second hashmap contains the edges with the vertex it connected to as the key and the weight as the value. My current problem is that when i try to remove vertices they are removed from the key set but they stay in the value(the second hashmap) as the key for that hashmap. IS THERE A WAY TO REMOVE THE VERTEX FROM THE KEYSET OF THE SECOND HASHMAP.
Code is as follows
constructor{
adjacencyMap = new HashMap<V, HashMap<V, Integer>>();
dataMap = new HashSet<V>();
}
removal method{
if(dataMap.contains(vertex)){
[Code]...
Which Is Efficient Arraylist Or Hashmap
Jan 30, 2014my project flow is html,css,js<--->ajax<-->jsp<--->jdbc(.java)<--->mysql. In that jdbc i am returning the records from the database and fill into the resultset. From the resultset i put all records in arraylist and passed to jsp then i am displaying data in the screen.Whether i can use arraylist, hashmap or treetable?
View Replies View RelatedJSP :: Iterating Hashmap Using Value Of Dropdown As Key
Jul 2, 2014I have a a hashmap in request attribute which is available to jsp file where i have a dropdown. Hashmap kay= value of this dropdown. As and when I select CLT i want to perform some opertation depending on value associated with that key in hashmap.
View Replies View RelatedAccessing HashMap With JSTL
Aug 18, 2014I have a HashMap returned from the server. There are two conditions
1. HashMap returned with only one set of key value pair or
2. HashMap with multiple set of data key value pairs.
Now in UI I have to display either text box or drop down box depending upon the size of map for that I am using length method
Java Code:
<c:choose>
<c:when test="${fn:length(myDto.mayMapInDto) eq 1}">
display text box
</c:when>
<c:otherwise>
display drop box
</c:otherwise>
</c:choose> mh_sh_highlight_all('java');
I can display drop box by looping but not sure how I can get only one element for text box. Tricky is I can't use key value to access since UI don't know what key will be returned.
How To Store Three Variables In HashMap
Feb 10, 2014So I just want to store a Key in a HashMap which can related to two values. For example, the Key "ABC" related to "Fire" which in turn relates to "Heat".
How can I code this in a HashMap?