Add CustomSet as a set

Author: zevolution

src/main/java/br/com/zevolution/datastructure/set/CustomSet.java

@@ -0,0 +1,52 @@
+package br.com.zevolution.datastructure.set;
+
+import java.util.ArrayList;
+
+import br.com.zevolution.datastructure.doublylinkedlist.DoublyLinkedList;
+
+public class CustomSet {
+
+	private ArrayList<DoublyLinkedList> set = new ArrayList<>(26);
+	private int totalElements = 0;
+	
+	public CustomSet() {
+		for (int i = 0; i < 26; i++) {
+			this.set.add(new DoublyLinkedList());
+		}
+	}
+
+	public void add(String word) {
+		if (!this.has(word)) {
+			this.set.get(this.getHashCode(word)).add(word);
+			this.totalElements++;
+		}
+	}
+
+	public boolean has(String word) {
+		return this.set.get(this.getHashCode(word)).has(word);			
+	}
+
+	public void remove(String word) {
+		if (this.has(word)) {
+			this.set.get(this.getHashCode(word)).remove(word);
+			this.totalElements--;
+		}
+	}
+	
+	public int size() {
+		return this.totalElements;
+	}
+
+	@Override
+	public String toString() {
+		return this.set.toString();
+	}
+
+	private int getHashCode(String word) {
+		if (word != null) {
+			return word.toLowerCase().charAt(0) % 26;
+		} else {
+			throw new NullPointerException();
+		}
+	}
+}

src/test/java/br/com/zevolution/datastructure/set/CustomSetTest.java

@@ -0,0 +1,45 @@
+package br.com.zevolution.datastructure.set;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Test;
+
+public class CustomSetTest {
+
+	@Test
+	public void should_Contain_OneRecordInCustomSet() {
+		CustomSet set = new CustomSet();
+		set.add("José Lucas");
+		
+		assertEquals(1, set.size());
+	}
+	
+	@Test
+	public void should_Be_Empty() {
+		CustomSet set = new CustomSet();
+		set.add("José Lucas");
+		
+		set.remove("José Lucas");
+		
+		assertEquals(0, set.size());
+	}
+	
+	@Test
+	public void should_NotBe_Duplicated() {
+		CustomSet set = new CustomSet();
+		set.add("José Lucas");
+		set.add("José Lucas");
+		set.add("José Lucas");
+		
+		assertEquals(1, set.size());
+	}
+	
+	@Test
+	public void should_Has_Word() {
+		CustomSet set = new CustomSet();
+		set.add("José Lucas");
+		
+		assertEquals(true, set.has("José Lucas"));
+	}
+
+}