CODEWITHSUNDEEP
javastringarraylist
Yeliz
Yeliz

Reputation: 25

How do I check the equality of a String and one String-attribute (out of many) of an entry in an ArrayList?

I'm trying to create a registry in form of an ArrayList which shall save all kinds of books I've read. The program has only two classes. One as a template for the entries (Name: Entry) and one which manages the entries in the ArrayList (Name: Registry).

These are the attributes of Entry:

private final String title;
private final String mangaka;
private final String year;
private final String genre;
private final String volumes;
private String completelyScanlated;
private String licensedInGerman;
private String read; 
private String comments;

and thus has this constructor:

public Entry(final String title, final String mangaka, final String year, final String genre, final String volumes, 
String completelyScanlated, String licencedInGerman, String read, String comment)
{
    this.title = title;
    this.mangaka = mangaka;
    this.year = year;
    this.genre = genre;
    this.volumes = volumes;
    this.completelyScanlated = completelyScanlated;
    this.licensedInGerman = licensedInGerman;
    this.read = read;
    this.comments = comments;
}

The class "Registry" has only one attribute:

ArrayList<Entry> entries = new ArrayList<Entry>();

The user creates an entry via 'Scanner' therefore by typing Strings into the console. The created object is saved in the ArrayList via:

Entry object = new Entry(title, mangaka, year, genre, volumes, completelyScanlated, licensedInGerman, read, comments);
    entries.add(object);

Now I want to check whether a String (which is also created with a console input) is equal to the attribute "title". I could check the equality of an input with the method ".contains()" but this method would compare all attributes. Is there a way to check only one attribute?

Here is the non-working code:

public void findEntry()
{
    Scanner input = new Scanner(System.in);

    System.out.println("Which title do you want to search for?");
    String searchedEntry = input.nextLine();
    System.out.println();
    if (entries.contains(searchedEntry)) {
        int x = entries.indexOf(searchedEntry);
        entries.get(x);
        //Entry.showDetails();
    }
}

The result is to given out via the console (that code is working though).

Thanks in advance

Upvotes: 1

Views: 65

Answers (2)

Paulo
Paulo

Reputation: 1498

Instead of 

if (entries.contains(searchedEntry)) {
    int x = entries.indexOf(searchedEntry);
    entries.get(x);
    //Entry.showDetails();
}

You can iterate through entries. Something like this:

for(Entry entry: entries) {
    if(entry.getTitle().equals(searchedEntry)) {
        // Do whatever it has to do.
    }
}

If title doesn't need to match the case, you can use:

if(entry.getTitle().equalsIgnoreCase(searchedEntry))

Upvotes: 0

ArcticLord
ArcticLord

Reputation: 4039

I assume you have a getter for your Title in your Entry class. Something like getTitle(). Then iterate over all entries and check if its title contains the search string.

public void findEntry(){
    Scanner input = new Scanner(System.in);

    System.out.println("Which title do you want to search for?");
    String searchedEntry = input.nextLine();
    System.out.println();
    for(Entry entry : entries){
        if(entry.getTitle().contains(input))
            entry.showDetails();   // or Whatever
    }
}

Even better whould it be to convert the title and the search string to lower cases befor.

if(entry.getTitle().toLowerCase().contains(input.toLowerCase()))

So you can search for "lord of THE rings" and will find "The Lord of the Rings: The Fellowship of the Ring".

Upvotes: 1

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