Replace String Literals If/elseIf block with Enum
<p>I'm new to using Java Enums and I've read that replace IF logic that compares String literals should be replaced with an Enum.  I don't quite understand how to replace my below code with an Enum, any ideas?  Based on the col value being passed into applyEQ, I need to do a base the next method call on it's value.  I do know the possible values of col ahead of time and I'm using a constants file for now.  Should I create an Enum and place it in my Interface of Constants file?</p>

<pre><code>public class FilterHelper implements IFilterHelper {

   private final EQuery eQuery;

   public FilterHelper(EQuery query) {
      eQuery = query;
   }

    @Override
    public void applyEQ(String col, String val) throws Exception {
        int return = 0;
        if (col.equalsIgnoreCase(EConstants.NAME)) {
            ret = Sample.addName(eQuery, val);
        } else if (col.equalsIgnoreCase(EConstants.KEYWORDS)) {
            ret = Sample.addKey(eQuery, val);
        } else if (col.equalsIgnoreCase(EConstants.ROLE)) {
            ret = Sample.addRole(eQuery, val);
        }  

        if (return != 0) {
            throw new Exception("failed");
        }
    }
}
</code></pre>

<p><strong>EConstants.java</strong></p>

<pre><code>public final class EConstants {    
    public static final String NAME = "cewName";
    public static final String KEYWORDS = "cewKeywords";
    public static final String ROLE = "cewRole";
}
</code></pre>
