i am going to type my code here and then I will explain my problem below.
for (int i = 0; i < sales.totalSales(); i++) {
EntidadGeo gec = sales.getSale(i).getCustomer();
EntidadGeo get = sales.getSale(i).getStore();
int[] c = geo.georeferenciar(sales.getSale(i).getCustomer().getCP(), ventas.getVenta(i).getCCustomer().getCalle(), ventas.getVenta(i).getCCustomer().getProvincia());
gec.setX(c[0]);
gec.setY(c[1]);
int[] c2 = geo.georeferenciar(ventas.getSale(i).getStore().getCP(), ventas.getVenta(i).getStore().getCalle(), ventas.getSale(i).getStore().getProvincia());
get.setX(c2[0]);
get.setY(c2[1]);
mapaventas.representar(gec, get);
}
I have that for loop, what i want to do in my project is to print in a map. The point is what I need to draw in the map are customers and stores and one store can sell to many customers at the same time. In my project I am using MVC pattern, this part belongs to Controller part, and in the model part i draw the map.
It works now but the problem is that my project draw one customer and one store instead of 4 customers per 1 store.
Thanks
Your problem is here:
mapaventas.representar(gec, get);
So it looks like you have a Map<Vendor, Client> which will only associate only one client per vendor. I have to guess at this because we have no knowledge what the method above does. If I am correct a better solution perhaps is to use a Map<Vendor, ArrayList<Client>>. so that a Vendor can be associated with multiple clients. Then you would do something like
ArrayList<Client> getList = mapaventas.get(gec);
// if the above is null, create the arraylist first and put it
// and the gec into the map.
getList.add(get);
Note that my variable names and types will not be the same as yours, but hopefully you will understand the concept I'm trying to get across. If not, please ask.
It sounds like your database has a one-to-many relation between Store and Customer. A corresponding object model might be List<Map<Store, List<Customer>>>. Because a Customer may trade at more than one Store, you want "to check there if there is an IdStore already drawn, and then I don't want to draw it."
One approach would be to iterate through the List and add entries to a Set<Location>. Because implementations of Set reject duplicate elements, only one copy would be present, and no explicit check would be required. As a concrete example using JMapViewer, you would add a MapMarker to the mapViewer for each Location in the Set, as shown here.
Related
I'm creating an extension for rapidminer using java. I have an array of elements of type Example and I need to covert it to a dataset of type ExampleSet.
Rapidminer's ExampleSet definition looks like this:
public interface ExampleSet extends ResultObject, Cloneable, Iterable<Example>
I need to pick certain elements from dataset and send it back, still as ExampleSet, however casting is not working and I can't simply create new ExampleSet object since it's an interface.
private ExampleSet generateSet(ExampleSet dataset){
List<Example> list = new ArrayList<Example>();
// pick elements from sent dataset and add them to newly created list above
return (ExampleSet)list;
}
You will need more than a simple explicit cast.
In RapidMiner, an ExampleSet is not just a collection of Example. It contains more complex information and logic.
Therefore, you need another approach to work with ExampleSets. Like you already said, it is just the interface, which lead us to choice of the right subtype.
For starters, (Since: 7.3) simply use one of ExampleSets class's methods .
You also need to define each Attribute this ExampleSet is going to have, namely the columns.
Below, I create one with a single Attribute called First
Attribute attributeFirst = AttributeFactory.createAttribute("First", Ontology.POLYNOMINAL);
ExampleSetBuilder builder = ExampleSets.from(attributeFirst);
builder.addDataRow(example.getDataRow());
ExampleSet result = builder.build();
You can also get the Attributes in a more generic way using:
Attribute[] attributes = example.getAttributes().createRegularAttributeArray();
ExampleSetBuilder builder = ExampleSets.from(attributes);
...
If you have many cases where you have to create or alter ExampleSet, I encourage you to write your own ExampleSetBuilder since the original implementation have many drawbacks.
You can also try searching for other extensions, which may already meet your requirements, and you do not need to create one of your own (belive me, it's not Headache-free).
the ExampleSet class is getting deprecated (but still perfectly fine to use).
You might want to consider switching over to the newer data set API called Belt (https://github.com/rapidminer/belt). It's faster and more intuitive to use. It's still actively developed, so feedback is also welcome.
Also if you have more specific questions, feel free to drop by the RapidMiner community (https://community.rapidminer.com/), where also many of the developers are very active.
I am new to java, learning Map from java oracle Docs,it says
What happens when you start mixing keys and values in the same bulk operation? Suppose you have a Map, managers, that maps each employee in a company to the employee's manager. We'll be deliberately vague about the types of the key and the value objects. It doesn't matter, as long as they're the same. Now suppose you want to know who all the "individual contributors" (or nonmanagers) are. The following snippet tells you exactly what you want to know.
Set<Employee> individualContributors = new HashSet<Employee>(managers.keySet());
individualContributors.removeAll(managers.values());
I am trying to code for above query,but i am not able to implement class Manager and Employee and its relation and put in a map and fetch managers.values()? Can someone give me example template for creating classes for above query with example?
In this example, the types for the managers and other employees are irrelevent. The managerial relationships between them are managed using the "managers" map. For example, you could set up the map using strings with code like this:
Map<String> managers = new HashMap<>();
managers.put("SoftwareEngineer1", "SoftwareEngineeringTeamManager");
managers.put("SoftwareEngineer2", "SoftwareEngineeringTeamManager");
managers.put("SoftwareEngineeringTeamManager", "MidLevelManager");
managers.put("MidLevelManager", "Executive");
managers.put("Executive", null);
This sets up two software engineers managed by a software engineer team manager, who is in turn managed by some mid level manager, who is in turn managed by some executive, who is managed by no one. The keyset in the map is
["SoftwareEngineer1", "SoftwareEngineer2", "SoftwareEngineeringTeamManager", "MidLevelManager", "Executive"]
And the values are
["SoftwareEngineeringTeamManager", "MidLevelManager", "Executive", null]
In the code sample you posted, the values are subtracted from the key set, so you end up with
["SoftwareEngineer1", "SoftwareEngineer2"]
These are the individual contributors you are looking for.
I've got loads of the following to implement.
validateParameter(field_name, field_type, field_validationMessage, visibleBoolean);
Instead of having 50-60 of these in a row, is there some form of nested hashmap/4d array I can use to build it up and loop through them?
Whats the best approach for doing something like that?
Thanks!
EDIT: Was 4 items.
What you could do is create a new Class that holds three values. (The type, the boolean, and name, or the fourth value (you didn't list it)). Then, when creating the HashMap, all you have to do is call the method to get your three values. It may seem like more work, but all you would have to do is create a simple loop to go through all of the values you need. Since I don't know exactly what it is that you're trying to do, all I can do is provide an example of what I'm trying to do. Hope it applies to your problem.
Anyways, creating the Class to hold the three(or four) values you need.
For example,
Class Fields{
String field_name;
Integer field_type;
Boolean validationMessageVisible;
Fields(String name, Integer type, Boolean mv) {
// this.field_name = name;
this.field_type = type;
this.validationMessageVisible = mv;
}
Then put them in a HashMap somewhat like this:
HashMap map = new HashMap<String, Triple>();
map.put(LOCAL STRING FOR NAME OF FIELD, new Field(new Integer(YOUR INTEGER),new Boolean(YOUR BOOLEAN)));
NOTE: This is only going to work as long as these three or four values can all be stored together. For example if you need all of the values to be stored separately for whatever reason it may be, then this won't work. Only if they can be grouped together without it affecting the function of the program, that this will work.
This was a quick brainstorm. Not sure if it will work, but think along these lines and I believe it should work out for you.
You may have to make a few edits, but this should get you in the right direction
P.S. Sorry for it being so wordy, just tried to get as many details out as possible.
The other answer is close but you don't need a key in this case.
Just define a class to contain your three fields. Create a List or array of that class. Loop over the list or array calling the method for each combination.
The approach I'd use is to create a POJO (or some POJOs) to store the values as attributes and validate attribute by attribute.
Since many times you're going to have the same validation per attribute type (e.g. dates and numbers can be validated by range, strings can be validated to ensure they´re not null or empty, etc), you could just iterate on these attributes using reflection (or even better, using annotations).
If you need to validate on the POJO level, you can still reuse these attribute-level validators via composition, while you add more specific validations are you´re going up in the abstraction level (going up means basic attributes -> pojos -> pojos that contain other pojos -> etc).
Passing several basic types as parameters of the same method is not good because the parameters themselves don't tell much and you can easily exchange two parameters of the same type by accident in the method call.
I'm reading in a set of data from serializable and as a result I get 2 sets of data, the old one that was already there and the new one that I've just loaded in. I managed to create a separate set of data and it kind of works but it's not the ideal solution here. I'm loading stuff into ArrayLists but that just seems to make the entries null rather than deleting them. So I was wondering how do I overwrite with serializable? Here is my current code that I use to load in the data:
//students.clear();
//modules.clear();
Model m = new Model();
m=Model.readModule("out.ser");
m.findStudent();
Like I said this created a new instance of Model, but I would rather have it replace the current instance but I'm unsure on how to do that.
If you have students and modules array lists then you can do:
students.clear();
modules.clear();
Model m = Model.readModule("out.ser");
students.addAll(m.getStudentsList());
modules.addAll(m.getModulesList());
Hope this helps.
I am quite new to java currently working on a not-so-simple web browser application in which I would like to record a permanent history file with a 2D array setup with 3 columns containing "Date Viewed", "URL", "How many times this URL has been viewed before".
Currently I have a temporary solution that only saves "URL" which is also used for "Back, Foward" features using an ArrayList.
private List tempHistory = new ArrayList();
I am reading through the Java documentation but I cannot put together a solution, unless I am missing the obvious there is no 2D array as flexible a ArrayList like in Python?
From your description it doesn't sound like you need a 2D array. You just have one dimension -- but of complex data types, right?
So define a HistoryItem class or something with a Date property for date viewed, URL for URL, int for view count.
Then you just want a List<HistoryItem> history = new ArrayList<HistoryItem>().
The reason I don't think you really want a 2D array-like thing is that it could only hold one data type, and you clearly have several data types at work here, like a date and a count. But if you really want a table-like abstraction, try Guava's Table.
No, there is no built-in 2D array type in Java (unless you use primitive arrays).
You could just use a list of lists (List<List>) - however, I think it is almost always better to use a custom type that you put into the list. In your case, you'd create a class HistoryEntry (with fields for "Date viewed", URL etc.), and use List<HistoryEntry>. That way, you get all the benefits a proper type gives you (typechecking, completion in an IDE, ability to put methods into the class etc.).
How do you plan to browse the history then? If you want to search the history for each url later on then ArrayList approach might not be efficient.
I would rather prefer a Map with URL as key.
Map<Url,UrlHistory> browseHistory = new HahMap<Url,UrlHistory> ();
UrlHistory will contains all the fields you want to associate with a url like no. of times page was accessed and all.