Develop Reference

Index in for method is not increasing

Ok this might seem easy but its been bugging my mind for days and I honestly don't know why it the index wont increase and get the other data. I dont know where to but the return. I placed it in 2 lines and the first one only gives the first row of data from the database and the second one only gives the last one from the database. (See commented out lines below). How to get each row that fits the if-statements?
Here's my code:
public Object[] populateTable(ArrayList<Outlet> outletList, String selection, int size, int monthCtr, String selDay){
for(int i = 0; i<outletList.size(); i++){
if(outletList.get(i).getCity().equalsIgnoreCase(selection)){
if(outletList.get(i).getStatus().equals("ACTIVE")){
bar = outletList.get(i).getBarangay();
code = Integer.toString(outletList.get(i).getCode());
name = outletList.get(i).getName();
data = new Object[]{bar, name, code};
//return data ->gives the first one in the database
}
}
}
}
//return data -> gives the last one in the database
}

You need to save all your results in another array and return that instead.
public Object[] populateTable(ArrayList<Outlet> outletList, String selection, int size, int monthCtr, String selDay)
{
List<object> result = new List<object>();
for(int i = 0; i<outletList.size(); i++)
{
if(outletList.get(i).getCity().equalsIgnoreCase(selection))
{
if(outletList.get(i).getStatus().equals("ACTIVE"))
{
bar = outletList.get(i).getBarangay();
code = Integer.toString(outletList.get(i).getCode());
name = outletList.get(i).getName();
data = new Object[]{bar, name, code};
result.Add(data);
}
}
}
return result.ToArray();
}

try this:
public List<Outlet> populateTable(ArrayList<Outlet> outletList, String selection, int size, int monthCtr, String selDay){
List<Outlet> data = new ArrayList<Outlet>();
for(int i = 0; i < outletList.size(); i++){
if(outletList.get(i).getCity().equalsIgnoreCase(selection) &&
outletList.get(i).getStatus().equals("ACTIVE")){
data.add(outletList.get(i));
}
}
return data;
}

Your problem here is as follow:
Your first return statement, will exit the for loop, and return
the first object, as your results have shown.
Your second return statement, will, as you have explained, only
return the last record that was iterated over in the for loop.
Your third problem is on this line data = new Object[]{bar, name,
code};. After every loop, you instantiate the data object to a new
array of objects, instead of adding the values to the array, so essentially, you are always creating an array of objects with 1 item in it, the last one that was iterated.
If you want to return all objects in the array, you should try the following:
public Object[] populateTable(ArrayList<Outlet> outletList, String selection, int size, int monthCtr, String selDay)
{
Object[] result = new Object[outletList.size()];
for (int i = 0; i < outletList.size(); i++)
{
if (outletList.get(i).getCity().equalsIgnoreCase(selection))
{
if (outletList.get(i).getStatus().equals("ACTIVE"))
{
bar = outletList.get(i).getBarangay();
code = Integer.toString(outletList.get(i).getCode());
name = outletList.get(i).getName();
var data = new { bar, name, code };
result[i] = data;
}
}
}
return result;
}

traversing a 2d array and adding indexs to a stack

I have a project for school to take my current pacman program and have pacman traverse the 2-d char array to find a pattern to complete the maze.
I am trying to use a stack and add specific index of my maze to the stack so when pacman reaches the index it pops off and he chooses a direction randomly to another index and so forth until all dots are eaten. My issue is taking my 2d array and finding the index values of the intersections and then adding them to a stack.
I am new to java and not really sure how to approach this I posted my maze I have and some code that will use the stack to find the sequence. Thanks in advanced.
private void create() {
String[] tier = new String[tall];
tier[0] = "|======================================|";
tier[1] = "|......................................|";
tier[2] = "|.====.==========================.====.|";
tier[3] = "|.||||............................||||.|";
tier[4] = "|.====.==========================.====.|";
tier[5] = "|......................................|";
tier[6] = "|.====================================.|";
tier[7] = "|......................................|";
tier[8] = "|.====.======.====----====.======.====.|";
tier[9] = "|.||||........|| ||........||||.|";
tier[10] = "|.||||.======.|| ||.======.||||.|";
tier[11] = "|.||||........|| ||....... ||||.|";
tier[12] = "|.====.======.============.======.====.|";
tier[13] = "|......................................|";
tier[14] = "|.===========..............===========.|";
tier[15] = "|.............===== =====.............|";
tier[16] = "|.=======.===.||$ $||.===.=======.|";
tier[17] = "|.|||||||.===.===== =====.===.|||||||.|";
tier[18] = "|.|||||||......................|||||||.|";
tier[19] = "|.|||||||.====================.|||||||.|";
tier[20] = "|.=======......................=======.|";
tier[21] = "|.==......====================......==.|";
tier[22] = "|.==.====.======........======.====.==.|";
tier[23] = "|....====........======........====....|";
tier[24] = "|======================================|";
for (int i = 0; i < tall; i++) {
array[i] = tier[i].toCharArray();
}
}
public boolean isPattern(Spot b, Spot e) {
Stack<Spot> ss = new Stack<Spot>();
Spot topPost, nextPost;
allOld();
ss.push(b);
markOld(b);
topPost = ss.peek();
while (!ss.empty() && (topPost.compareTo(e) != 0)) {
nextPost = getNextSpot(topPost);
if (nextPost == null) {
ss.pop();
} else {
ss.push(nextPost);
markOld(nextPost);
}
topPost = ss.peek();
}
if (ss.empty()) {
return false;
} else {
return true;
}
}
public void index(int x, int y, int dx, int dy){
x=array.length;
y=array[x].length;
for( int i=0;i <x;i++){
for(int j =0; j<y;j++){
if(array[i].get(i))//this should determine if its aninersection and then add to the stack
}
}
}
}
the last method is where i am getting stuck. I dont know how to get the specific index values. I guess i can enter them manually but I am sure there is an easier way. Please comment if need more context on the problem and Thanks again.

Adding element to array of array

I have an array of arrays with color variable
Color [] [] bin = new Color [64] [];
afterwards I want to insert colors into this array
Im looping through a list of colors and tmpColor is the particular color in the loop. I need to insert it into the specific loop it belongs.
int idx = 16* (tmpColor.getRed()/64) + 4*(tmpColor.getGreen()/64) + (tmpColor.getBlue()/64);
bin[idx].push(tmpColor);
However this doesn't seem to work. How do I add a color into the array in the specific index?

How I solve it is the following: instead of creating an array of arrays I created and array of ArrayLists
int size = 64;
ArrayList<Color>[] lists = new ArrayList[size];
for( int i = 0; i < size; i++) {
lists[i] = new ArrayList<Color>();
}
After that I pushed the elements to their particular bin ( in this case in lists)
lists[idx].add(tmpColor);
Afterwards getting the lenght and the first color in the array is s follows:
for (ArrayList<Color> p : lists){
System.out.println("size of bin" + p.size());
if (p.isEmpty())
continue;
else {
System.out.println("list" + p.get(0));
}
}

If you need a List of colors for your index you can use a Map:
private Map<Integer, List<Color>> bin = new HashMap<Integer, List<Color>>();
int idx = 16* (tmpColor.getRed()/64) + 4*(tmpColor.getGreen()/64) + (tmpColor.getBlue()/64);
if(bin.get(idx)==null) bin.put(idx, new ArrayList<Color>());
bin.get(idx).add(tmpColor); //This should be exactly what you need
You can use also different structures like List<List<Color>> or List<Color>[]. Every structure relays on a List since List can be updated and created without knowing the initial length.
What I would do is create a separate class for color bin and some useful methods within:
public class Bin{
private List<Color> colors = new ArrayList<Color>();
public void addColor(Color col){
this.colors.add(col);
}
public List<Color> getColors(){
return this.colors;
}
public boolean hasColor(Color col){
return colors.contains(col);
}
//and so on...
}
And the best structure for your goal now is a map with lazy initialization:
private Map<Integer, Bin> myBinsOfColors = new HashMap<Integer, Bin>();
int idx = 16* (tmpColor.getRed()/64) + 4*(tmpColor.getGreen()/64) + (tmpColor.getBlue()/64);
if(myBinsOfColors.get(idx)==null) myBinsOfColors.put(idx, new Bin()); //Lazy
myBinsOfColors.get(idx).addColor(tmpColor); //This should be exactly what you need
To get the avarage and the number of colors you can implement two methods in the Bin class:
public class Bin{
private List<Color> colors = new ArrayList<Color>();
//As above.
public Color calculateAverage() {
Integer red = 0;
Integer blue = 0;
Integer green = 0;
if(!colors.isEmpty()) {
for (Color col : colors) {
red+= col.getRed();
green+= col.getGreen();
blue+= col.getBlue();
}
return new Color(red/colors.size(), green/colors.size(), blue/colors.size());
}
return null;
}
public int getColorCount(){
return this.colors.size();
}
//and so on...
}

Converting a MATLAB Javabuilder output object element to an array

I've been issued the task of using MATLAB Builder to convert a MATLAB function into a Java class, now I have gotten to a point where I have the results from one class being fed into another and since the MATLAB builder will only output an object, I'm having issues.
import java.util.*;
import com.mathworks.toolbox.javabuilder.*;
public class mainKrigTau {
public static void main(String[] args) {
Object[] resultT = null;
Object[] resultK = null;
Object[] resultB = null;
krigingTau Tau = null;
krigingTau Krig = null;
Branin branin = null;
try {
Tau = new krigingTau();
Krig = new krigingTau();
branin = new Branin();
resultT = Tau.LPtau(1, 100, 2, 1234);
List<Object> X = Arrays.asList(resultT[0]);
System.out.println(X);
System.out.println((X.size()));
} catch (MWException e)
{
e.printStackTrace();
} finally
{
}
So basically the output of the Tau class is a 2D array, so the array is embedded into the resultT[] object, how to I get access to this array? One method I have tried is as above, changing it into an array list, X outputs the array, but I can't access the components of the array. X.size = 1, not 100 which is the actual size of the array. edit - just to add, all the examples I can find just output the result object and display it, rather than do anything with it.

Okay a software engineer nearby came to the rescue. It's a bit of a roundabout way but it works.
try {
Tau = new krigingTau();
Krig = new krigingTau();
branin = new Branin();
resultT = Tau.LPtau(1, 100, 2, 1234);
List<Object> X = Arrays.asList(resultT[0]);
if (X.get(0) instanceof MWNumericArray) {
MWNumericArray mw= (MWNumericArray) X.get(0);
ArrayList<Point> lists = new ArrayList<Point>();
for(int i = 1; i <= mw.numberOfElements()/2; i++){
Object o = mw.get(i);
System.out.println(o);
Double x = (Double) mw.get(i);
Double y = (Double) mw.get((mw.numberOfElements()/2)+i);
Point p = new Point(x.doubleValue(),y.doubleValue());
lists.add(p);
}
for(int i = 1; i < mw.numberOfElements()/2; i++)
{
resultB = branin.branin(1, lists.get(i).array);
System.out.println(resultB[0]);
}
where point sets the values of x and y into an array, so set it to an new MWNumericArray and do Object.get(i) but this flattens the array which is not ideal.

I have to return a value from a function that is called multiple times and I am unable to do that

I am stuck.
The following function is supposed to return currVm, an integer. But if I make a return I will break the loop and next time when this function is called,the same process will begin again.
What shall I do, so that I continue from where I left off ? I tried making static variables but I that didn't help me.
#Override
public int getNextAvailableVm() {
Set<String> dataCenters = confMap.keySet();
for (String dataCenter : dataCenters) {
LinkedList<DepConfAttr> list = confMap.get(dataCenter);
Collections.sort(list, new MemoryComparator());
int size = list.size() - 1;
int count = 0;
while(size >= 0) {
DepConfAttr dca = (DepConfAttr)list.get(count);
int currVm = dca.getVmCount();
int c = 0;
while(c <= currVm) {
allocatedVm(currVm);
c++;
return currVm;
}
count++;
size--;
}
}
return 0;
}
The for-each loop assigns a new data center that acts as a key for the confMap.The list that I get as a value, is sorted.Then a loop is run till it escapes its size.Inside this while loop, another while loop is run from where a function named allocatedVm of the inherited class is called. A parameter named currVm is passed to it.
This is the variable that I need to return. What shall I do to return this variable ? I have to start from I left off. I mean the next call should appear to be the next step, whatever it was, while executing the loop.

Add List<Integer> object to your class, and change your method as follows:
private Iterator<Integer> availableVms = null;
#Override
public int getNextAvailableVm() {
if (availableVms != null) {
if (availableVms.hasNext()) {
return availableVms.next();
}
return 0;
}
List<Integer> tmp = new ArrayList<Integer>();
Set<String> dataCenters = confMap.keySet();
for (String dataCenter : dataCenters) {
LinkedList<DepConfAttr> list = confMap.get(dataCenter);
Collections.sort(list, new MemoryComparator());
int size = list.size() - 1;
int count = 0;
while(size >= 0) {
DepConfAttr dca = (DepConfAttr)list.get(count);
int currVm = dca.getVmCount();
int c = 0;
while(c <= currVm) {
allocatedVm(currVm);
c++;
tmp.add(currVm);
}
count++;
size--;
}
}
availableVms = tmp.iterator();
return availableVms.hasNext() ? availableVms.next() : 0;
}
The idea is to pre-generate the entire list, and store its iterator for future use. Before entering the method you check if the availableVms iterator has been prepared. If it has been prepared, grab the next item off of it if it's available; otherwise, return zero.
If the list has not been prepared yet, run your algorithm, and add the results to a temporary list tmp. Once the list is ready, grab its iterator, and use it for subsequent invocations.