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POBetter way to call common method on randomly selected object in java
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  1. POBetter way to call common method on randomly selected object in java
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    copied!<p>Nice day to everybody.</p> <p>I have an abstract class with the method runRandomExercise(), and several classes that extends it to add different kind of exercise. </p> <p>I now want to chose a random type exercise, so I need to randomly choose one of the classes, and call runRandomExercise() on that.</p> <p>For now I am manually coding this, which is not the very best solution I think. However, I can’t store just the classes in the array since the class type is different, and if I use object[] I can’t call the runRandomExercise() method. Any smart way to handle this?</p> <p>Here is my code till now. It works, but it’s gonna be a pain to add other classes...</p> <pre><code>/*Specific classes that extend abstract class TrainingClass with the runRandomExercise() method*/ private MatheMagic mMathMag; private Mnemonics mMnemonics; private String[] mTrainingClasses; /*Initialize classes*/ mMathMag = new MatheMagic(); mMnemonics = new Mnemonics(); /*Manually store classe names*/ mTrainingClasses = new String[2]; mTrainingClasses[0] = "mMathMag"; mTrainingClasses[1] = "mMnemonics"; /*Return random exercise*/ public String[] RandomExercise() { Random aGenerator = new Random(); /*Get random class name*/ int rnd = aGenerator.nextInt(mTrainingClasses.length); String aChosen = mTrainingClasses[rnd]; String[] aRes = new String[2]; if (aChosen == "mMathMag") { aRes = mMathMag.runRandomExercise(); } else if (aChosen == "mMnemonics") { aRes = mMnemonics.runRandomExercise(); } return aRes; } </code></pre> <p>EDIT Here is how TrainingClass is defined: </p> <pre><code>/** Common interface for all exercises */ public interface Exercise { public String[] run(); } /** Common interface for all training classes */ public abstract class TrainingClass { private Random mRandGen = new Random(); public ArrayList&lt;Exercise&gt; mExerciseTypes = new ArrayList&lt;Exercise&gt;(); /** Run a random exercise */ public String[] runRandomExercise() { int i = mRandGen.nextInt(mExerciseTypes.size()); return mExerciseTypes.get(i).run(); } } /*Specific training class*/ public class MatheMagic extends TrainingClass { public MatheMagic() { class SomeExercise implements Exercise { public String[] run() { String[] mRes = new String[2]; mRes[0] = "Question type 1"; mRes[1] = "Answer type 1"; return mRes; } } class SomeOtherExercise implements Exercise { public String[] run() { String[] mRes = new String[2]; mRes[0] = "Question type 2"; mRes[1] = "Answer type 2"; return mRes; } } SomeExercise mN = new SomeExercise(); SomeOtherExercise mS = new SomeOtherExercise(); mExerciseTypes.add(mN); mExerciseTypes.add(mS); } } </code></pre>
 

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