CODEWITHSUNDEEP
javaarraylisthashmapsorting
Saurabh
Saurabh

Reputation: 157

Sorting an arraylist of hashmap according to a value field of the hashmap

Basically, I have an arraylist declared like : 

private ArrayList<HashMap<String, String>> songsList = 
                             new ArrayList<HashMap<String, String>>();

now what I want to do is that for each key I want to give two value fields. Can it be done??

Secondly I want to sort the key-value pair according to the value pair. So how can it be achieved?

Upvotes: 0

Views: 1070

Answers (2)

David Grant
David Grant

Reputation: 14223

That's a lot of String objects. Have you considered encapsulating your data structure using an Object, rather than a complex collection of strings? For example, assuming your map key is a song:

public Song implements Comparable<Song> {
    private String title;
    private String artist;
    private String album;

    public Song(String title, String artist, String album) {
       ...
    }

    public int compareTo(Song s) {
        // sorting logic
    }

    ... // getters, setters, equals & hashCode
}

Then, create your list of songs:

List<Song> songs = new ArrayList<Song>();
songs.add(new Song("Dancing Queen", "Abba", "Arrival"); // I had to find this on Wikipedia
...

Then sort them:

Collections.sort(songs);

Upvotes: 1

aa8y
aa8y

Reputation: 3942

You can implement the comparable interface for the sorting problem of yours. And for having multiple values for a value in a map, create a class with the required values with getters and setters. And use the class as a value against the key.

Upvotes: 0

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