CODEWITHSUNDEEP
javadesign-patternsvalidationfile-upload
Marcus Leon
Marcus Leon

Reputation: 56669

Design patterns for validating a file

We have to validate a CSV file containing various configuration parameters. Are there any standard design patterns to do this type of validation.

More details:

Upvotes: 4

Views: 2817

Answers (3)

Pierre
Pierre

Reputation: 35246

I know a friend of mine uses JBOSS DROOLS to validate this kind of files.

Upvotes: -1

sateesh
sateesh

Reputation: 28673

You can use the Strategy pattern to for validating the records. Have an abstract base class to represent a Record and you can use Factory Method ,or Simple Factory to create concrete instances of various Record types.
Your specification is not complete. Here is the code sample that implements Strategy pattern with a simplistic assumption about your record. 

interface Validator {
     // since it is not clear what are the attributes that matter for a record, 
     // this takes an instance of Record. 
     // Modify to accept relevant attribures of Record
     public boolean validate (Record r);
 }

 class ConcreteValidator implements Validator {
      // implements a validation logic
 }

// implements Comparable so that it can be used in rules that compare Records
abstract class Record implements Comparable<Record> {
    protected Validator v;
    abstract void setValidator(Validator v);
    public boolean isValid() {
        return v.validate(this);
    }
}

class ConcreteRecord extends Record {
   // alternatively accept a Validaor during the construction itself 
   // by providing a constructor that accepts a type of Validator
   // i.e. ConcreteRecord(Validator v) ...
    void setValidator(Validator v) {
        this.v = v;
    }

    // implementation of method from Comparable Interface
    public int compareTo(final Record o) {... }
}

public class Test {
    public static void main(String[] args) {
        // Store the read in Records in a List (allows duplicates)
        List<Record> recordList = new ArrayList<Record>();
        // this is simplistic. Your Record creation mode might be 
        // more complex, And you can use a Factory Method 
        // (or Simple Factory) for creation of  ConcreteRecord
        Record r = new ConcreteRecord();
        r.setValidtor(new ConcretedValidator());
        if (r.isValid()) {
            // store only valid records
            recordList.add(r);
        }

       // do further processing of Records stored in recordList
    }

}

Upvotes: 4

D.C.
D.C.

Reputation: 15588

The template pattern may help: http://en.wikipedia.org/wiki/Template_method_pattern

You set up a scaffolding for your validation in general terms, then hand off the algorithm to a delegate that knows how to handle specifics at various points.

Upvotes: 0

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