Backport to Java 7

README.md

@@ -3,19 +3,19 @@
 [![Dependency Status](https://www.versioneye.com/user/projects/550195a04a1064db0e000328/badge.svg?style=flat)](https://www.versioneye.com/user/projects/550195a04a1064db0e000328)
 [![Coverage Status](https://coveralls.io/repos/lind/machineprocess/badge.svg?branch=master)](https://coveralls.io/r/lind/machineprocess?branch=master)
 
-Simple State Machine with transitions, guards, composite state.
+Simple State Machine with transitions, guards and actions.
 
-...but without sub-state machine, deferred signals, event queues...
+...but without composite state, sub-state machine, deferred signals, event queues...
 
 Define the State Machine by subclassing State Machine and using the builders in the constructor. Se tests for usage.
 
 <!-- language: lang-java -->
         State onHold = state(ON_HOLD)
-                .transition(HURL_PHONE).guardedBy(event -> PHONE_HURLED_AGAINST_WALL.equals(event.getName()))
+                .transition(HURL_PHONE).guardedBy(PHONE_HURLED_AGAINST_WALL)
                 .to(phoneDestroyed)
-                .transition(HANG_UP).guardedBy(event -> HUNG_UP.equals(event.getName()))
+                .transition(HANG_UP).guardedBy(HUNG_UP)
                 .to(offHook)
-                .transition(TAKE_OFF_HOLD).onTransition(stopMuzak).guardedBy(event -> TOOK_OFF_HOLD.equals(event.getName()))
+                .transition(TAKE_OFF_HOLD).onTransition(stopMuzak).guardedBy(TOOK_OFF_HOLD)
                 .to(connected)
                 .build();
 
@@ -24,21 +24,8 @@ Define the State Machine by subclassing State Machine and using the builders in
 ### Phone State Machine Diagram
 Inspired by [simplestatemachine](http://simplestatemachine.codeplex.com/)
 
-**Phone State Machine** (Generated from code by [Graphviz](http://www.graphviz.org/))
+Generated from code by [Graphviz](http://www.graphviz.org/) - Usage: dot -o outputfile -Tbmp inputfile.dot
 
-![Phone State Machine Diagram](PhoneStateMachine.bmp "Phone State Machine Diagram")
-
-### ATM State Machine Diagram
-Inspired by [ATM Bank](http://www.uml-diagrams.org/bank-atm-uml-state-machine-diagram-example.html)
-
-**ATM State Machine** (Generated from code by [Graphviz](http://www.graphviz.org/))
-
-![ATM State Machine](ATMStateMachine.bmp)
+See: [Graphviz command-line-invocation](http://www.graphviz.org/content/command-line-invocation)
 
-The composite state **ServingCustomer**
-
-![Serving Customer](ServingCustomer.bmp)
-
-**A model containing the ATM state machine and the inner states of the composite state** (not generated from code)
-
-![ATM State Machine Diagram](ATMStateMachineDiagram.png)
+![Phone State Machine Diagram](PhoneStateMachine.bmp "Phone State Machine Diagram")

pom.xml

@@ -10,10 +10,10 @@
     <name>Machine Process</name>
 
     <properties>
-        <assertj.version>3.0.0</assertj.version>
+        <assertj.version>3.2.0</assertj.version>
         <junit.version>4.12</junit.version>
-        <jdk.version>1.8</jdk.version>
-        <logback.version>1.1.2</logback.version>
+        <jdk.version>1.7</jdk.version>
+        <logback.version>1.1.3</logback.version>
         <slf4j.version>1.7.12</slf4j.version>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     </properties>
@@ -61,12 +61,12 @@
                 <configuration>
                     <repoToken>jxpXA5E9hYylQJWwgh1uZbcpVMMHzPiTT</repoToken>
                 </configuration>
-                <version>3.1.0</version>
+                <version>4.0.0</version>
             </plugin>
             <plugin>
                 <groupId>org.jacoco</groupId>
                 <artifactId>jacoco-maven-plugin</artifactId>
-                <version>0.7.4.201502262128</version>
+                <version>0.7.5.201505241946</version>
                 <executions>
                     <execution>
                         <id>prepare-agent</id>

src/main/java/org/nextstate/statemachine/Action.java

@@ -1,6 +1,5 @@
 package org.nextstate.statemachine;
 
-@FunctionalInterface
 public interface Action {
     void perform();
 }

src/main/java/org/nextstate/statemachine/SimpleState.java

@@ -2,16 +2,15 @@
 
 import java.util.ArrayList;
 import java.util.List;
-import java.util.Optional;
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 public class SimpleState implements State {
     private final Logger log = LoggerFactory.getLogger(this.getClass());
 
-    protected Optional<Action> entry = Optional.empty();
-    protected Optional<Action> exit = Optional.empty();
+    protected Action entry = null;
+    protected Action exit = null;
 
     protected final String name;
     protected final List<Transition> transitions = new ArrayList<>();
@@ -33,42 +32,51 @@ public void addTransitions(List<Transition> transitionList) {
     }
 
     @Override public void onEntry() {
-        entry.ifPresent(Action::perform);
+        if (entry != null) {
+            entry.perform();
+        }
     }
 
     @Override public void onExit() {
-        exit.ifPresent(Action::perform);
+        if (exit != null) {
+            exit.perform();
+        }
     }
 
-    @Override public Optional<State> execute(String event) {
+    @Override public State execute(String event) {
         return stateTransition(event);
     }
 
-    public Optional<State> stateTransition(String event) {
+    public State stateTransition(String event) {
 
-        Optional<Transition> matchedTransition = transitions.stream()
-                .filter(t -> t.guardEvent == null || t.guardEvent.equals(event))
-                .findFirst();
+        Transition matchedTransition = null;
+        for (Transition t : transitions) {
+            if (t.guardEvent == null || t.guardEvent.equals(event)) {
+                matchedTransition = t;
+            }
+        }
 
-        log.debug("execute - {} event: {} ", name, event, (matchedTransition.isPresent() ?
-                " transition to state: " + matchedTransition.get().getTargetState().getName() :
+        log.debug("stateTransition state:{} - event:{} {}", name, event, (matchedTransition != null ?
+                " transition to state: " + matchedTransition.getTargetState().getName() :
                 " no transition match."));
 
-        if (!matchedTransition.isPresent()) {
-            log.debug("execute - No transition match event: {} in state: {}", event, name);
-            return Optional.empty();
+        if (matchedTransition != null) {
+            if (matchedTransition.onTransition != null) {
+                log.debug("stateTransition - Transition match event: {} in state: {}", event, name);
+                matchedTransition.onTransition.perform();
+            }
+            return matchedTransition.getTargetState();
         }
-
-        Transition transition = matchedTransition.get();
-        transition.onTransition.ifPresent(Action::perform);
-        return Optional.ofNullable(transition.getTargetState());
+        return null;
     }
 
     public boolean transitionToFinalState() {
-        Optional<Transition> transition = transitions.stream().filter(
-                t -> t.guardEvent.equals(FinalState.FINAL_EVENT)).findFirst();
-
-        return transition.isPresent() && (transition.get().getTargetState() instanceof FinalState);
+        for (Transition t : transitions) {
+            if (t.guardEvent.equals(FinalState.FINAL_EVENT)) {
+                return t.getTargetState() instanceof FinalState;
+            }
+        }
+        return false;
     }
 
     @Override public void toDot(StringBuilder sb) {
@@ -112,12 +120,12 @@ public Transition.TransitionBuilder<StateBuilder> transition(String name) {
         }
 
         public StateBuilder onEntry(Action action) {
-            state.entry = Optional.ofNullable(action);
+            state.entry = action;
             return this;
         }
 
         public StateBuilder onExit(Action action) {
-            state.exit = Optional.ofNullable(action);
+            state.exit = action;
             return this;
         }
 

src/main/java/org/nextstate/statemachine/State.java

@@ -1,14 +1,12 @@
 package org.nextstate.statemachine;
 
-import java.util.Optional;
-
 public interface State {
 
     String getName();
 
     boolean transitionToFinalState();
 
-    Optional<State> execute(String event);
+    State execute(String event);
 
     void onEntry();
 

src/main/java/org/nextstate/statemachine/StateMachine.java

@@ -2,7 +2,6 @@
 
 import java.util.ArrayList;
 import java.util.List;
-import java.util.Optional;
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -56,12 +55,15 @@ public String getActiveStateConfiguration() {
 
     public void activeStateConfiguration(String stateName) {
 
-        Optional<State> state = states.stream().filter(s -> stateName.equals(s.getName())).findFirst();
-        state.orElseThrow(() -> new IllegalStateException("No state named " + stateName
-                + " exists. Add all states to the StateMachine before setting active state configuration."));
-
-        activeState = state.get();
-        log.debug("activeStateConfiguration - active state: {}", activeState.getName());
+        for (State state : states) {
+            if (state.getName().equals(stateName)) {
+                activeState = state;
+                log.debug("activeStateConfiguration - active state: {}", activeState.getName());
+                return;
+            }
+        }
+        throw new IllegalStateException("No state named " + stateName
+                + " exists. Add all states to the StateMachine before setting active state configuration.");
     }
 
     public void execute(String event) {
@@ -70,12 +72,12 @@ public void execute(String event) {
         }
         log.debug("execute - activeState: " + activeState.getName() + " event: " + event);
 
-        Optional<State> state = activeState.execute(event);
+        State state = activeState.execute(event);
 
         // Check if new active state and execute onExit on the old and onEntry on the new ...
-        if (state.isPresent()) {
+        if (state != null) {
             activeState.onExit();
-            activeState = state.get();
+            activeState = state;
             activeState.onEntry();
             log.debug("execute - new active state: {}", activeState.getName());
         }
@@ -109,15 +111,17 @@ public String toDot(boolean showActiveState) {
 
         getActiveState().toDot(sb);
 
-        getStates().stream().filter(state -> state != getActiveState()).forEach(state -> {
+        for (State state :states){
+            if (state != activeState) {
             sb.append(state.getName().replaceAll("\\s+", "_"));
             sb.append("[label=\"");
             sb.append(state.getName());
             sb.append("\"");
             sb.append("];");
             sb.append(System.lineSeparator());
             state.toDot(sb);
-        });
+            }
+        }
         sb.append("} ");
         sb.append(System.lineSeparator());
         return sb.toString();

src/main/java/org/nextstate/statemachine/Transition.java

@@ -2,13 +2,12 @@
 
 import java.util.ArrayList;
 import java.util.List;
-import java.util.Optional;
 
 public class Transition {
     private final String name;
     private State targetState;
     protected String guardEvent;
-    protected Optional<Action> onTransition;
+    protected Action onTransition;
 
     public Transition(String guardEvent, State state, String name, Action onTransition) {
         if (state == null) {
@@ -20,7 +19,7 @@ public Transition(String guardEvent, State state, String name, Action onTransiti
         this.guardEvent = guardEvent;
         this.targetState = state;
         this.name = name;
-        this.onTransition = Optional.ofNullable(onTransition);
+        this.onTransition = onTransition;
     }
 
     public State getTargetState() {

src/test/java/org/nextstate/statemachine/PhoneStateMachine.java

@@ -64,41 +64,44 @@ class PhoneStateMachine extends StateMachine {
     private static final String TAKE_OFF_HOLD = "TakeOffHold";
     private static final String HURL_PHONE = "HurlPhone";
 
-    {
-        Action playMuzak = () -> System.out.println("PlayMuzak");
-        Action stopMuzak = () -> System.out.println("StopMuzak");
+    Action playMuzak = new Action() {
+        @Override public void perform() {
+            System.out.println("PlayMuzak");
+        }
+    };
+    Action stopMuzak = new Action() {
+        @Override public void perform() {
+            System.out.println("StopMuzak");
+        }
+    };
 
+    {
         SimpleState offHook = state(OFF_HOOK)
-                .onEntry(() -> System.out.println("In Sysout Action!")).build();
+                .onEntry(new Action() {
+                    @Override public void perform() {
+                        System.out.println("In Sysout Action!");
+                    }}).build();
         State phoneDestroyed = state(PHONE_DESTROYED).build();
         SimpleState connected = state(CONNECTED).build();
         State onHold = state(ON_HOLD)
                 .transition(HURL_PHONE).guardedBy(PHONE_HURLED_AGAINST_WALL)
                 .to(phoneDestroyed)
                 .transition(HANG_UP).guardedBy(HUNG_UP)
                 .to(offHook)
-                .transition(TAKE_OFF_HOLD).onTransition(stopMuzak)
-                .guardedBy(TOOK_OFF_HOLD)
+                .transition(TAKE_OFF_HOLD).onTransition(stopMuzak).guardedBy(TOOK_OFF_HOLD)
                 .to(connected)
                 .build();
         connected.addTransitions(transitions()
-                .transition(PLACE_ON_HOLD)
-                .onTransition(playMuzak).guardedBy(PLACED_ON_HOLD)
-                .to(onHold)
-                .transition(HANG_UP).guardedBy(HUNG_UP)
-                .to(offHook)
-                .transition(LEAVE_MESSAGE).guardedBy(MESSAGE_LEFT)
-                .to(offHook)
+                .transition(PLACE_ON_HOLD).onTransition(playMuzak).guardedBy(PLACED_ON_HOLD).to(onHold)
+                .transition(HANG_UP).guardedBy(HUNG_UP).to(offHook)
+                .transition(LEAVE_MESSAGE).guardedBy(MESSAGE_LEFT).to(offHook)
                 .build());
         State ringing = state(RINGING)
-                .transition(CONNECT_CALL).guardedBy(CALL_CONNECTED)
-                .to(connected)
-                .transition(HANG_UP).guardedBy(HUNG_UP)
-                .to(offHook)
+                .transition(CONNECT_CALL).guardedBy(CALL_CONNECTED).to(connected)
+                .transition(HANG_UP).guardedBy(HUNG_UP).to(offHook)
                 .build();
         offHook.addTransitions(transitions()
-                .transition(CALL_DIAL).guardedBy(CALL_DIALED)
-                .to(ringing).build());
+                .transition(CALL_DIAL).guardedBy(CALL_DIALED).to(ringing).build());
         addStates(Arrays.asList(offHook, phoneDestroyed, onHold, connected, ringing));
         activeState(offHook);
         validate();

src/test/java/org/nextstate/statemachine/PhoneStateMachineTest.java

@@ -15,6 +15,7 @@ public void one_transition() {
         // Given
         StateMachine phone = new PhoneStateMachine();
 
+        System.out.println(phone.toDot(false));
         // When
         phone.execute(PhoneStateMachine.CALL_DIALED);
 

src/test/java/org/nextstate/statemachine/StateTest.java

@@ -3,8 +3,6 @@
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.nextstate.statemachine.Transition.transitions;
 
-import java.util.Optional;
-
 import org.junit.Test;
 
 public class StateTest {
@@ -20,10 +18,10 @@ public void transition_match() {
                 .transition(CALL_DIAL).guardedBy(CALL_DIALED)
                 .to(to).build());
 
-        Optional<State> target = from.execute(CALL_DIALED);
+        State target = from.execute(CALL_DIALED);
 
-        assertThat(target.isPresent());
-        assertThat(target.get().getName()).isEqualTo("To");
+        assertThat(target).isNotNull();
+        assertThat(target.getName()).isEqualTo("To");
     }
 
     @Test