#111 Implementation of Step Builder pattern

step-builder/src/main/java/com/iluwatar/stepbuilder/CharacterStepBuilder.java

@@ -0,0 +1,168 @@
+package com.iluwatar.stepbuilder;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * The Step Builder class.
+ */
+
+public class CharacterStepBuilder {
+
+	private CharacterStepBuilder() {
+	}
+
+	public static NameStep newBuilder() {
+		return new CharacterSteps();
+	}
+
+	/**
+	 * First Builder Step in charge of the Character name.
+	 * Next Step available : ClassStep
+	 */
+	public interface NameStep {
+		ClassStep name(String name);
+	}
+
+	/**
+	 * This step is in charge of setting the Character class (fighter or wizard).
+	 * Fighter choice : Next Step available : WeaponStep
+	 * Wizard choice : Next Step available : SpellStep
+	 */
+	public interface ClassStep {
+		WeaponStep fighterClass(String fighterClass);
+		SpellStep wizardClass(String wizardClass);
+	}
+
+	/**
+	 * This step is in charge of the weapon.
+	 * Weapon choice : Next Step available : AbilityStep
+	 * No weapon choice : Next Step available : BuildStep
+	 */
+	public interface WeaponStep {
+		AbilityStep withWeapon(String weapon);
+		BuildStep noWeapon();
+	}
+
+	/**
+	 * This step is in charge of the spell.
+	 * Spell choice : Next Step available : AbilityStep
+	 * No spell choice : Next Step available : BuildStep
+	 */
+	public interface SpellStep {
+		AbilityStep withSpell(String spell);
+		BuildStep noSpell();
+	}
+
+	/**
+	 * This step is in charge of abilities.
+	 * Next Step available : BuildStep
+	 */
+	public interface AbilityStep {
+		AbilityStep withAbility(String ability);
+		BuildStep noMoreAbilities();
+		BuildStep noAbilities();
+	}
+
+	/**
+	 * This is the final step in charge of building the Character Object.
+	 * Validation should be here.
+	 */
+	public interface BuildStep {
+		Character build();
+	}
+
+
+	/**
+	 * Step Builder implementation.
+	 */
+	private static class CharacterSteps
+	    implements NameStep, ClassStep, WeaponStep, SpellStep, AbilityStep, BuildStep {
+
+		private String name;
+		private String fighterClass;
+		private String wizardClass;
+		private String weapon;
+		private String spell;
+		private List<String> abilities = new ArrayList<>();
+
+		@Override
+		public ClassStep name(String name) {
+			this.name = name;
+			return this;
+		}
+
+		@Override
+		public WeaponStep fighterClass(String fighterClass) {
+			this.fighterClass = fighterClass;
+			return this;
+		}
+
+		@Override
+		public SpellStep wizardClass(String wizardClass) {
+			this.wizardClass = wizardClass;
+			return this;
+		}
+
+		@Override
+		public AbilityStep withWeapon(String weapon) {
+			this.weapon = weapon;
+			return this;
+		}
+
+		@Override
+		public BuildStep noWeapon() {
+			return this;
+		}
+
+		@Override
+		public AbilityStep withSpell(String spell) {
+			this.spell = spell;
+			return this;
+		}
+
+		@Override
+		public BuildStep noSpell() {
+			return this;
+		}
+
+		@Override
+		public AbilityStep withAbility(String ability) {
+			this.abilities.add(ability);
+			return this;
+		}
+
+		@Override
+		public BuildStep noMoreAbilities() {
+			return this;
+		}
+
+		@Override
+		public BuildStep noAbilities() {
+			return this;
+		}
+
+		@Override
+		public Character build() {
+			Character character = new Character(name);
+
+			if (fighterClass != null) {
+				character.setFighterClass(fighterClass);
+			} else {
+				character.setWizardClass(wizardClass);
+			}
+
+			if (weapon != null) {
+				character.setWeapon(weapon);
+			} else {
+				character.setSpell(spell);
+			}
+
+			if (!abilities.isEmpty()) {
+				character.setAbilities(abilities);
+			}
+
+			return character;
+		}
+	}
+}