Merge pull request #6143 from dionisPrifti/BAEL-2441-Java-Enums-for_State-Machines

BAEL-2441: Providing example for State Machines with Enums
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Eric Martin 2019-01-20 10:59:44 -06:00 committed by GitHub
commit e4a74bd6f6
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package com.baeldung.algorithms.enumstatemachine;
public enum LeaveRequestState {
Submitted {
@Override
public LeaveRequestState nextState() {
System.out.println("Starting the Leave Request and sending to Team Leader for approval.");
return Escalated;
}
@Override
public String responsiblePerson() {
return "Employee";
}
},
Escalated {
@Override
public LeaveRequestState nextState() {
System.out.println("Reviewing the Leave Request and escalating to Department Manager.");
return Approved;
}
@Override
public String responsiblePerson() {
return "Team Leader";
}
},
Approved {
@Override
public LeaveRequestState nextState() {
System.out.println("Approving the Leave Request.");
return this;
}
@Override
public String responsiblePerson() {
return "Department Manager";
}
};
public abstract String responsiblePerson();
public abstract LeaveRequestState nextState();
}

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package com.baeldung.algorithms.enumstatemachine;
import static org.junit.Assert.assertEquals;
import org.junit.Test;
public class LeaveRequestStateUnitTest {
@Test
public void givenLeaveRequest_whenStateEscalated_thenResponsibleIsTeamLeader() {
LeaveRequestState state = LeaveRequestState.Escalated;
assertEquals(state.responsiblePerson(), "Team Leader");
}
@Test
public void givenLeaveRequest_whenStateApproved_thenResponsibleIsDepartmentManager() {
LeaveRequestState state = LeaveRequestState.Approved;
assertEquals(state.responsiblePerson(), "Department Manager");
}
@Test
public void givenLeaveRequest_whenNextStateIsCalled_thenStateIsChanged() {
LeaveRequestState state = LeaveRequestState.Submitted;
state = state.nextState();
assertEquals(state, LeaveRequestState.Escalated);
state = state.nextState();
assertEquals(state, LeaveRequestState.Approved);
state = state.nextState();
assertEquals(state, LeaveRequestState.Approved);
}
}