java/src/org/apache/qetest/Datalet.java

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/*
 *
 * Datalet.java
 *
 */
package org.apache.qetest;

import java.util.Hashtable;

/**
 * Minimal interface defining a datalet, a single set of data 
 * for a simple test case.
 * <p>A Datalet defines a single group of data that a matching 
 * Testlet needs to execute it's simple test case.  Normally,
 * Testlets and Datalets are matched.</p>
 *
 * <p>This makes creating data-driven tests simpler, by separating 
 * the test algorithim from the definition of the test data.  Note 
 * that logging what happened during the test is already separated 
 * out into the Logger interface.</p>
 *
 * <p>Normally Datalets will simply be collections of public members
 * that can be written or read by anyone.  An enclosing test can 
 * simply create or load a number of Datalets and then pass them 
 * to a Testlet to execute the whole bunch of them.</p>
 *
 * <p>One way to look at a Datalet is basically an intelligent 
 * Properties / Hashtable / InputSource, designed for a 
 * specific set of data.  They can be loaded from a variety of 
 * inputs and will intelligently create the right kind of data 
 * that their corresponding Testlet is expecting.
 * For example, and DOM-based InputSource Datalet might be 
 * loaded from a number of Strings denoting filenames or URLs.
 * The Datalet would then know how to parse each of the files 
 * into a DOM, which a Testlet could then use directly.</p>
 *
 * <p>//@todo what metaphor is best? I.e. Should Datalets break OO
 * paradigms and just have public members, or should they work more 
 * like a Hashtable with some Properties-like features thrown in?
 * Or: what are the most important 
 * things to optimize: syntactic sugar-like simplicity for callers; 
 * more functionality for different datatypes; ease of use by 
 * inexperienced coders (perhaps testers who are just learning Java);
 * ease of use by experienced coders?</p>
 * 
 *
 * <p>//@todo Should we add a getParameterInfo() method?</p>
 * @author Shane_Curcuru@lotus.com
 * @version $Id$
 */
public interface Datalet
{

    /**
     * Accesor method for a brief description of this Datalet.  
     *
     * @return String describing the specific set of data 
     * this Datalet contains (can often be used as the description
     * of any check() calls made from the Testlet).
     */
    public abstract String getDescription();


    /**
     * Accesor method for a brief description of this Datalet.  
     * Datalets must have this as a read/write property, since many 
     * users will programmatically construct Datalets.
     *
     * @param s description to use for this Datalet.
     */
    public abstract void setDescription(String s);


    /**
     * Load fields of this Datalet from a Hashtable.
     * Note many datalets might take in a Properties block 
     * instead for simple String-valued data.
     *
     * @param Hashtable to load; Datalet should attempt to fill 
     * in as many member variables as possible from this, leaving 
     * any non-specified variables null or some default; behavior 
     * if null is passed is undefined
     */
    public abstract void load(Hashtable h);


    /**
     * Load fields of this Datalet from an array.
     * This allows most Datalets to be initialized from a main()
     * command line or the like.  For any String-valued types, or 
     * types that can easily be derived from a String, this makes 
     * running ad-hoc tests very easy.
     *
     * @param args array of Strings, as if from the command line;
     * Datalet should attempt to fill in as many member variables 
     * as possible from this, defining the order itself, leaving 
     * any non-specified variables null or some default; behavior 
     * if null is passed is undefined
     */
    public abstract void load(String[] args);

}  // end of class Datalet