scrambler

src/edu/macalester/comp124/stringtransformer/Scrambler.java

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+package edu.macalester.comp124.stringtransformer;
+
+import acm.util.RandomGenerator;
+
+/**
+ * Created by Marcus Ulmer on 2/27/14.
+ */
+public class Scrambler extends StringTransformer{
+    @Override
+    public String transform(String s) {
+        //deals with caps
+        boolean wordHasLeadingCap = false;
+        if (Character.isUpperCase(s.charAt(0))){
+            wordHasLeadingCap = true;
+        }
+        s= s.toLowerCase();
+        RandomGenerator generator = new RandomGenerator();
+        char[] wordArray;
+        wordArray = new char[s.length()]; //following pattern from JavaDoc for array
+        char[] scrambled;
+        scrambled = new char[s.length()];
+        //puts s into an array
+        for(int i=0; i < s.length();i++){
+            wordArray[i] = s.charAt(i);
+        }
+        //picks characters at random and puts them in the new array,
+        //then puts them at the end of their array and doesn't scan that far.
+        for(int i=0; i < s.length();i++){
+            int place = generator.nextInt(0,wordArray.length - (i+1));
+            scrambled[i] = wordArray[place];
+            //code based on template from <http://stackoverflow.com/questions/13766209/effective-swapping-of-elements-of-an-array-in-java>
+            char temp = wordArray[place]; //intended idea here is to put the used letters at the end of the string and then not read them -
+            wordArray[place] = wordArray[wordArray.length - (i+1)];
+            wordArray[wordArray.length - 1] = temp;
+        }
+        String scrambledWord = "";
+        for (int i=0; i < scrambled.length; i++){
+            scrambledWord += scrambled[i];
+            //checks if the word should be capitalised
+            if (wordHasLeadingCap && i == 0){
+                scrambledWord = scrambledWord.toUpperCase();
+            }
+        }
+
+        return scrambledWord;
+    }
+    @Override
+    public String toString() {
+        return "All scrambled.";
+    }
+}

test/edu/macalester/comp124/stringtransformer/ScramblerTest.java

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+package edu.macalester.comp124.stringtransformer;
+
+import org.junit.Test;
+
+import static junit.framework.Assert.assertEquals;
+
+/**
+ * Created by Marcus Ulmer on 2/27/14.
+ */
+public class ScramblerTest {
+    private final StringTransformer scrambler = new Scrambler();
+    /*I ended up doing mostly manual testing in a console program environment:
+    I had a bunch of errors with length vs. index of arrays, so that was more suited.
+    Couldn't figure out how to use || with strings, so testing options were pretty limited
+    due to randomness.*/
+    @Test
+    public void dealsWithCaps() {
+        assertEquals(("A"), scrambler.transform("A"));
+    }
+
+    @Test
+    public void preservesString() {
+        assertEquals("a", scrambler.transform("a"));
+    }
+}