Re: Array reference in for loop

From:
Patricia Shanahan <pats@acm.org>
Newsgroups:
comp.lang.java.programmer
Date:
Tue, 14 Aug 2007 13:31:24 -0700
Message-ID:
<f9t3hm$v5$1@ihnp4.ucsd.edu>
Daniel Pitts wrote:

On Aug 14, 9:15 am, Patricia Shanahan <p...@acm.org> wrote:

IchBin wrote:

tes...@hotmail.com wrote:

I have a validate method in a bean class that works and now I want to
condense it into a for loop.

Here is what I have:

//firstname and lastname are declared earlier
public boolean validate()
{
   boolean allOk=true;
   if (firstName.equals("")) {
     errors.put("firstName","Please enter your first name");
     allOk=false;
   }
   if (lastName.equals("")) {
     errors.put("lastName","Please enter your last name");
     allOk=false;
   }
   return allOk;
 }

My attempt doesnt work because I cant seem to figure out how to put
the array reference in the key part of the errors.put method:

public boolean validate()
{
   boolean allOk=true;
   String [] myarray = {firstname, lastname}
   for(int i=0;i < myarray.length;i++)
   {
   if (myarray[i].equals("")) {
     errors.put(myarray[i],"Please enter your " + myarray[i]);
     allOk=false;
   }
   }
   return allOk;
 }

The results dont validate any of my data so I assume I have something
wrong with my array. Please advise.


Quick and dirty:

   public boolean validate()
   {
       boolean allOk=true;
       String [] myarray = {firstName, lastName,
                           "first Name","last Name"};
       for(int i=0;i < myarray.length;i++){
           if (myarray[i].equals("")) {
               errors.put(myarray[i] + " Please enter your " +
                                         myarray[i+2]);
               allOk=false;
           }
       }
       return allOk;
   }


There are two needs for a String array, providing the labels for using
in the message and holding the input. Why not use two arrays, one for
each job?

    public boolean validate()
    {
        boolean allOk=true;
        String[] input = {firstName, lastName};
        String[] labels = {"first Name","last Name"};
        for(int i=0;i < input.length;i++){
            if (input[i].equals("")) {
                errors.put(input[i] + " Please enter your " +
                                          labels[i]);
                allOk=false;
            }
        }
        return allOk;
    }

I don't like names like "myarray", because they are often associated
with constructs that do not have a single clear purpose.

Patricia


I don't like parallel arrays myself, and I don't think this is a job
for an array actually.

public void validateHelper(String fieldName, String fieldValue, String
message) {
   if (fieldValue == null || fieldValue.equals("")) {
       errors.put(fieldName, fieldMessage);
   }
}

public void validate() {
   validateHelper("firstName", firstName, "Please enter your first
name.");
   validateHelper("lastName", lastName, "Please enter your last
name.");
}


Yes, that is a better design.

Patricia

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