How do I get the key from Map in a List and do a get rest request in Java-CodePudding

I want to do a get request and want to get all the jobs who have the "teacher" in it. In this case the map value 2 and 3.

How do I get there if I execute the code below then I only get the value from the Map 2. The best way is over a List? But how do I do it?

I have this method.

@GET
@Path("jobs")
public Job getJobsId(@QueryParam("id") int id, @QueryParam("description") String description) {

    for (final Map.Entry<Integer, Job> entry : jobs.entrySet()) {
        if (entry.getValue().getDescription().toLowerCase().contains(description.toLowerCase())) {
            System.out.println("I DID IT");
            System.out.println(entry.getKey());
            return berufe.get(entry.getKey());
        }

    }
    return berufe.get(id);
}

and this Map:

jobs.put(1, new jobs(1, 1337, "student"));
jobs.put(2, new jobs(2, 420, "teacher"));
jobs.put(3, new jobs(3, 69, "schoolteacher"));

---------------------------------EDIT----------------------------------

If I do this:

@GET
@Path("jobs")
public Collection<Job> getJobsId(@QueryParam("id") int id, @QueryParam("description") String description) {

    final Set<Beruf> result = new HashSet<>();

    for (final Map.Entry<Integer, Job> entry : jobs.entrySet()) {
        if (entry.getValue().getDescription().toLowerCase().contains(description.toLowerCase()) == true) {

            result.add(jobs.get(entry.getKey()));
        } else {
          return jobs.values();
        }

    }
    return result;
}

I get with a discription all Map values back and without I get an Error.

What do I do wrong here?

CodePudding user response：

Your method getJobsId() returns on the first item it finds (inside the if statement), that's why you only get one result.

The usual pattern to collect a number of results would be to instantiate a suitable Collection before the for loop, and add each item that is found to this collection. Then, after the for loop, return the collection. I don't understand your code completely, but it would be something similar to the below (I'm sure it won't work if you just copy-paste, so read and understand what is going on ;-) ):

Set<Beruf> result = new HashSet<>();
for (final Map.Entry<Integer, Job> entry : jobs.entrySet()) {
  if (entry.getValue().getDescription().toLowerCase().contains(description.toLowerCase())) {
    result.add(berufe.get(entry.getKey()));
  }
}
return result;

Since Java 8, it has been much more concise (readable) to use the Streams interface and call .filter (and maybe .map) on it, then .collect the stream to a suitable collection and return that. Something similar to:

return jobs.entrySet().stream()
  .filter(entry -> (entry.getValue().getDescription().toLowerCase().contains(description.toLowerCase())))
  .map(entry -> berufe.get(entry.getKey()))
  .collect(Collectors.toSet());

CodePudding user response：

A function can return only one element. If there more than one hit, you have to return an object that can take on multiple elements. As you already mentioned a list, as an representant of a collection, can do this job. For your use case is a map a better option:

@GET
@Path("jobs")
 public Job getJobsId(@QueryParam("id") int id, @QueryParam("description") String description)
 {
    //Declare an object that can take on multiple elements
    var Map<Job> jobList = new HashMap<>();
    for (final Map.Entry<Integer, Job> entry : jobs.entrySet())
    {
        if (entry.getValue().getDescription().toLowerCase().contains(description.toLowerCase()))
        {
                System.out.println("I DID IT");
                System.out.println(entry.getKey());
                jobList.put(entry.getKey(), job.get(entry.getKey()));
        }
    
    }
    return jobList.get(id);
}

CodePudding user response：

First of all, you should do is design the API correctly, for example:

@GET
@Path("jobs")
public List<Integer> searchJobsIdByDescription(@QueryParam("description") String description) {
    ...
}

Important: you must give a suitable name to the method (f.e: searchJobsIdByDescription), your method should only do one thing, so you declare only the parameters needed to do that thing (f.e: (@QueryParam("description") String description)) and return the expected type (List<Integer>).

Pay attention to the annotation @Path("jobs"), you have to avoid matching the previous ones

Next, you should carefully read @frIV's answer