Created
September 28, 2017 23:17
-
-
Save btforsythe/eb89f81c4aa12f6a5c2c7f31947e3808 to your computer and use it in GitHub Desktop.
Dorothy's Fears
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
package oz; | |
import java.util.Iterator; | |
public class AnimalsIterator implements Iterator<String> { | |
private String[] animals; | |
int index; // defaults to zero | |
public AnimalsIterator(String... animals) { | |
this.animals = animals; | |
} | |
@Override | |
public String next() { | |
// you would usually see this as: | |
// return animals[index++]; | |
String currentAnimal = animals[index]; | |
index++; | |
return currentAnimal; | |
} | |
@Override | |
public boolean hasNext() { | |
return index < animals.length; | |
} | |
} |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
package oz; | |
import static org.junit.Assert.assertEquals; | |
import static org.junit.Assert.assertFalse; | |
import static org.junit.Assert.assertTrue; | |
import java.util.Iterator; | |
import org.junit.Assert; | |
import org.junit.Test; | |
public class AnimalsIteratorTest { | |
@Test | |
public void shouldReturnTheFirstElement() { | |
// arrange | |
AnimalsIterator underTest = new AnimalsIterator("Lions"); | |
// act | |
String result = underTest.next(); | |
// assert | |
assertEquals("Lions", result); | |
} | |
@Test | |
public void shouldReturnSecondElement() { | |
String[] animals = { "Lions", "Tigers" }; | |
AnimalsIterator underTest = new AnimalsIterator(animals); | |
underTest.next(); // Lions | |
String result = underTest.next(); | |
assertEquals("Tigers", result); | |
} | |
@Test | |
public void shouldHaveNext() { /// start with the positive case | |
AnimalsIterator underTest = new AnimalsIterator("Ducks"); | |
boolean result = underTest.hasNext(); | |
assertTrue(result); | |
} | |
@Test | |
public void shouldNotHaveNext() { | |
AnimalsIterator underTest = new AnimalsIterator(); | |
boolean result = underTest.hasNext(); | |
assertFalse(result); | |
} | |
@Test | |
public void shouldBeAnIterator() { | |
AnimalsIterator underTest = new AnimalsIterator(); | |
boolean isAnIterator = (underTest instanceof Iterator); | |
assertTrue(isAnIterator); | |
} | |
} |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
package oz; | |
import java.util.Iterator; | |
public class DorothysFears implements Iterable<String> { | |
private String[] fears = { "Lions", "Tigers", "Bears" }; | |
@Override | |
public Iterator<String> iterator() { | |
return new AnimalsIterator(fears); | |
} | |
} |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
package oz; | |
public class OzApp { | |
public static void main(String[] args) { | |
DorothysFears fears = new DorothysFears(); | |
System.out.println("Dorothy's fears are"); | |
for(String f: fears) { | |
System.out.println(f); | |
} | |
System.out.println("Oh my."); | |
} | |
} |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment