Retrieving multiple values from an arraylist

Question

I have saved values retrieved from a database in java to an arraylist. I have used a class to save the data to the array list as shown below.

    ArrayList<NewSms> details = new ArrayList<NewSms>();
    try{
        Statement query = conn.createStatement();
        ResultSet result = query.executeQuery("Select `senderAddress,message,linkid from sdp_smsincoming where status=0 AND smsServiceActivationNumber =1234 ");`

        while(result.next()){
            String address = result.getString("senderAddress");
            String message = result.getString("message");
            String linkid = result.getString("linkid");

            NewSms smsdetails = new NewSms();
            smsdetails.set_address(address);
            smsdetails.set_message(message);
            smsdetails.set_linkid(linkid);
            details.add(smsdetails);;
        }
    }

However i now want to retrieve the values individually per row,from another class in the program.How can i do this?By individually i mean getting the address,message and linkid per row in the arraylist.

How can you identify a row? You can use HashMap<IDENTIFIER_TYPE, NewSms> and get from map by some identifier. — BobTheBuilder
– BobTheBuilder, Commented Aug 28, 2013 at 8:31
Now you have the details arrayList.. Just return it from the function and use an iterator — Konza
– Konza, Commented Aug 28, 2013 at 8:35

Jon Skeet · Accepted Answer · 2013-08-28 09:11:14Z

5

However i now want to retrieve the values individually per row,from another class in the program.How can i do this?

You just access each NewSms in the list. To access one by index, you could use:

NewSms sms = details.get(2); // Or whatever
// Now access the properties of sms

Or to access each of them in turn, use an enhanced for loop:

for (NewSms sms : details) {
    // Now access the properties of sms
}

Note that to comply with Java naming conventions, your NewSms class should have methods such as getAddress, setAddress - not set_address.

Also note that you need to close your result set / statement / connection - if you're using Java 7, you can use a try-with-resources statement; otherwise you should use finally blocks.

EDIT: If your problem is actually just returning the list, that's easy:

public List<NewSms> loadSmsDetails() {
    // Code as before...

    return details;
}

Then just call it from your other class:

// Where repository is a reference to an instance of the class containing the above method
List<NewSms> allDetails = repository.loadSmsDetails();

edited Aug 28, 2013 at 9:11

answered Aug 28, 2013 at 8:32

Jon Skeet

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2 Comments

mungaih pk Over a year ago

Thanks for your comment Jon,but am to retrieve the vallues in a different class,details would not work here.More like a method returns the arraylist above.so when i call the method form another class,how do i retrieve the values in the arraylist?using details cannot work here.

Jon Skeet Over a year ago

@mungaihkamau: Well yes, you'd need to make this method return the ArrayList. If your question was actually about how you return a list from one method, it would have been helpful if you'd said so. Will edit my answer.

Crickcoder · Accepted Answer · 2013-08-28 08:34:27Z

0

for(NewSms smsdetails:details){ 
String address = smsdetails.get_address();
String message = smsdetails.get_message();
String linkId = smsdetails.get_linkid();
}

answered Aug 28, 2013 at 8:34

Crickcoder

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Comments

Scorpion · Accepted Answer · 2013-08-28 08:42:49Z

0

However i now want to retrieve the values individually per row,from another class in the program

You need to pass the arraylist to the another class and iterate over it there to get the individual elements. The idea is to use a common araylist - to store the values from the resultset and in another class to iterate through them.

answered Aug 28, 2013 at 8:42

Scorpion

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