Final State Machine

build.gradle

@@ -0,0 +1,14 @@
+group 'ru.bvn13'
+version '1.0'
+
+apply plugin: 'java'
+
+sourceCompatibility = 1.8
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    testCompile group: 'junit', name: 'junit', version: '4.12'
+}

gradlew

@@ -0,0 +1,172 @@
+#!/usr/bin/env sh
+
+##############################################################################
+##
+##  Gradle start up script for UN*X
+##
+##############################################################################
+
+# Attempt to set APP_HOME
+# Resolve links: $0 may be a link
+PRG="$0"
+# Need this for relative symlinks.
+while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+        PRG="$link"
+    else
+        PRG=`dirname "$PRG"`"/$link"
+    fi
+done
+SAVED="`pwd`"
+cd "`dirname \"$PRG\"`/" >/dev/null
+APP_HOME="`pwd -P`"
+cd "$SAVED" >/dev/null
+
+APP_NAME="Gradle"
+APP_BASE_NAME=`basename "$0"`
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS=""
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD="maximum"
+
+warn () {
+    echo "$*"
+}
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+}
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "`uname`" in
+  CYGWIN* )
+    cygwin=true
+    ;;
+  Darwin* )
+    darwin=true
+    ;;
+  MINGW* )
+    msys=true
+    ;;
+  NONSTOP* )
+    nonstop=true
+    ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD="$JAVA_HOME/jre/sh/java"
+    else
+        JAVACMD="$JAVA_HOME/bin/java"
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD="java"
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
+    MAX_FD_LIMIT=`ulimit -H -n`
+    if [ $? -eq 0 ] ; then
+        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
+            MAX_FD="$MAX_FD_LIMIT"
+        fi
+        ulimit -n $MAX_FD
+        if [ $? -ne 0 ] ; then
+            warn "Could not set maximum file descriptor limit: $MAX_FD"
+        fi
+    else
+        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
+    fi
+fi
+
+# For Darwin, add options to specify how the application appears in the dock
+if $darwin; then
+    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
+fi
+
+# For Cygwin, switch paths to Windows format before running java
+if $cygwin ; then
+    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
+    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
+    JAVACMD=`cygpath --unix "$JAVACMD"`
+
+    # We build the pattern for arguments to be converted via cygpath
+    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
+    SEP=""
+    for dir in $ROOTDIRSRAW ; do
+        ROOTDIRS="$ROOTDIRS$SEP$dir"
+        SEP="|"
+    done
+    OURCYGPATTERN="(^($ROOTDIRS))"
+    # Add a user-defined pattern to the cygpath arguments
+    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
+        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
+    fi
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    i=0
+    for arg in "$@" ; do
+        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
+        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
+
+        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
+            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
+        else
+            eval `echo args$i`="\"$arg\""
+        fi
+        i=$((i+1))
+    done
+    case $i in
+        (0) set -- ;;
+        (1) set -- "$args0" ;;
+        (2) set -- "$args0" "$args1" ;;
+        (3) set -- "$args0" "$args1" "$args2" ;;
+        (4) set -- "$args0" "$args1" "$args2" "$args3" ;;
+        (5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
+        (6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
+        (7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
+        (8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
+        (9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+    esac
+fi
+
+# Escape application args
+save () {
+    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
+    echo " "
+}
+APP_ARGS=$(save "$@")
+
+# Collect all arguments for the java command, following the shell quoting and substitution rules
+eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+
+# by default we should be in the correct project dir, but when run from Finder on Mac, the cwd is wrong
+if [ "$(uname)" = "Darwin" ] && [ "$HOME" = "$PWD" ]; then
+  cd "$(dirname "$0")"
+fi
+
+exec "$JAVACMD" "$@"

gradlew.bat

@@ -0,0 +1,84 @@
+@if "%DEBUG%" == "" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%" == "" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS=
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if "%ERRORLEVEL%" == "0" goto init
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto init
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:init
+@rem Get command-line arguments, handling Windows variants
+
+if not "%OS%" == "Windows_NT" goto win9xME_args
+
+:win9xME_args
+@rem Slurp the command line arguments.
+set CMD_LINE_ARGS=
+set _SKIP=2
+
+:win9xME_args_slurp
+if "x%~1" == "x" goto execute
+
+set CMD_LINE_ARGS=%*
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS%
+
+:end
+@rem End local scope for the variables with windows NT shell
+if "%ERRORLEVEL%"=="0" goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega

settings.gradle

@@ -0,0 +1,2 @@
+rootProject.name = 'FinalStateMachine'
+

src/main/java/ru/bvn13/fsm/Condition.java

@@ -0,0 +1,17 @@
+package ru.bvn13.fsm;
+
+/**
+ * Created by bvn13 on 28.12.2017.
+ */
+public class Condition implements ConditionBehaviour {
+
+    private FSM fsm;
+    protected void setFSM(FSM fsm) {
+        this.fsm = fsm;
+    }
+
+    @Override
+    public boolean check() {
+        return false;
+    }
+}

src/main/java/ru/bvn13/fsm/ConditionBehaviour.java

@@ -0,0 +1,8 @@
+package ru.bvn13.fsm;
+
+/**
+ * Created by bvn13 on 28.12.2017.
+ */
+public interface ConditionBehaviour {
+    boolean check();
+}

src/main/java/ru/bvn13/fsm/Exceptions/AmbiguousTransitionException.java

@@ -0,0 +1,20 @@
+package ru.bvn13.fsm.Exceptions;
+
+import java.util.List;
+
+/**
+ * Created by bvn13 on 28.12.2017.
+ */
+public class AmbiguousTransitionException extends FSMException {
+    public AmbiguousTransitionException(String message) {
+        super(message);
+    }
+    public AmbiguousTransitionException(String from, List<String> next) {
+        super("");
+        String msg = "";
+        for (String to : next) {
+            msg += (msg.length() > 0 ? ", " : "") + to;
+        }
+        this.message = String.format("Ambiguous transition from state %s. Candidates are: %s", from, msg);
+    }
+}

src/main/java/ru/bvn13/fsm/Exceptions/BrokenTransitionException.java

@@ -0,0 +1,10 @@
+package ru.bvn13.fsm.Exceptions;
+
+/**
+ * Created by bvn13 on 28.12.2017.
+ */
+public class BrokenTransitionException extends FSMException {
+    public BrokenTransitionException(String from) {
+        super("Broken transition from: "+from);
+    }
+}

src/main/java/ru/bvn13/fsm/Exceptions/ConditionExistsException.java

@@ -0,0 +1,10 @@
+package ru.bvn13.fsm.Exceptions;
+
+/**
+ * Created by bvn13 on 28.12.2017.
+ */
+public class ConditionExistsException extends FSMException {
+    public ConditionExistsException(String from, String to) {
+        super(String.format("Condition exists: %s -> %s", from, to));
+    }
+}

src/main/java/ru/bvn13/fsm/Exceptions/FSMException.java

@@ -0,0 +1,23 @@
+package ru.bvn13.fsm.Exceptions;
+
+import java.io.PrintWriter;
+import java.io.StringWriter;
+
+/**
+ * Created by bvn13 on 28.12.2017.
+ */
+public class FSMException extends Exception {
+    protected String message;
+    public FSMException(String message) {
+        this.message = message;
+    }
+    protected String getStackTraceString() {
+        StringWriter sw = new StringWriter();
+        PrintWriter pw = new PrintWriter(sw);
+        this.printStackTrace(pw);
+        return sw.toString();
+    }
+    public void printStackTrace() {
+        System.out.println(String.format("FSMException: %s / %s", message, getStackTraceString()));
+    }
+}

src/main/java/ru/bvn13/fsm/Exceptions/NotInitedException.java

@@ -0,0 +1,13 @@
+package ru.bvn13.fsm.Exceptions;
+
+/**
+ * Created by bvn13 on 28.12.2017.
+ */
+public class NotInitedException extends FSMException {
+    public NotInitedException(String message) {
+        super(message);
+    }
+    public NotInitedException() {
+        super("FSM is not inited");
+    }
+}

src/main/java/ru/bvn13/fsm/Exceptions/StateExistsException.java

@@ -0,0 +1,10 @@
+package ru.bvn13.fsm.Exceptions;
+
+/**
+ * Created by bvn13 on 28.12.2017.
+ */
+public class StateExistsException extends FSMException {
+    public StateExistsException(String stateName) {
+        super(String.format("State exist: %s", stateName));
+    }
+}

src/main/java/ru/bvn13/fsm/Exceptions/TransitionMissedException.java

@@ -0,0 +1,10 @@
+package ru.bvn13.fsm.Exceptions;
+
+/**
+ * Created by bvn13 on 28.12.2017.
+ */
+public class TransitionMissedException extends FSMException {
+    public TransitionMissedException(String from) {
+        super(String.format("Missed conditions from: %s", from));
+    }
+}

src/main/java/ru/bvn13/fsm/FSM.java

@@ -0,0 +1,124 @@
+package ru.bvn13.fsm;
+
+import ru.bvn13.fsm.Exceptions.*;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Created by bvn13 on 28.12.2017.
+ */
+public class FSM {
+
+    private boolean done = false;
+    private State initialState;
+    private State currentState;
+    private Map<String, State> states;
+    private Map<String, Map<String, ConditionBehaviour>> transitions;
+
+    public FSM() {
+        this.states = new HashMap<>();
+        this.transitions = new HashMap<>();
+    }
+
+    private void checkStateExist(String name) throws StateExistsException {
+        if (this.states.containsKey(name)) {
+            throw new StateExistsException(name);
+        }
+    }
+
+    public void init() throws NotInitedException {
+        currentState = initialState;
+        if (currentState == null) {
+            throw new NotInitedException();
+        }
+        done = false;
+        currentState.beforeEvent();
+        currentState.process();
+    }
+
+    public State getCurrentState() {
+        return currentState;
+    }
+
+
+    public void next() throws FSMException {
+        if (done) {
+            return;
+        }
+        currentState.afterEvent();
+        if (currentState.isFinish()) {
+            done = true;
+            return;
+        }
+        if (!transitions.containsKey(currentState.getName())) {
+            throw new TransitionMissedException(currentState.getName());
+        }
+        Map<String, ConditionBehaviour> conditions = transitions.get(currentState.getName());
+        List<String> nextStates = new ArrayList<>();
+        for (String key : conditions.keySet()) {
+            if (conditions.get(key) == null) {
+                nextStates.add(key);
+            } else if(conditions.get(key).check()) {
+                nextStates.add(key);
+            }
+        }
+        if (nextStates.size() > 1) {
+            throw new AmbiguousTransitionException(currentState.getName(), nextStates);
+        }
+        if (nextStates.size() == 0) {
+            throw new BrokenTransitionException(currentState.getName());
+        }
+        State nextState = states.get(nextStates.get(0));
+        nextState(nextState);
+    }
+
+    private void nextState(State state) {
+        state.beforeEvent();
+        currentState = state;
+        currentState.process();
+    }
+
+    public void initState(State state) throws FSMException {
+        state.setFSM(this);
+        addState(state);
+        initialState = state;
+    }
+
+    public void addState(State state) throws FSMException {
+        checkStateExist(state.getName());
+        this.states.put(state.getName(), state);
+    }
+
+    public void addTransition(String fromState, String toState) throws FSMException {
+        storeTransition(fromState, toState, null);
+    }
+
+    public void addTransition(String fromState, String toState, Condition condition) throws FSMException {
+        condition.setFSM(this);
+        storeTransition(fromState, toState, condition);
+    }
+
+    public void addTransition(String fromState, State toState) throws FSMException {
+        addState(toState);
+        addTransition(fromState, toState.getName());
+    }
+
+    public void addTransition(String fromState, State toState, Condition condition) throws FSMException {
+        addState(toState);
+        addTransition(fromState, toState.getName(), condition);
+    }
+
+    private void storeTransition(String fromState, String toState, Condition condition) throws FSMException {
+        if (!transitions.containsKey(fromState)) {
+            transitions.put(fromState, new HashMap<>());
+        }
+        if (transitions.get(fromState).containsKey(toState)) {
+            throw new ConditionExistsException(fromState, toState);
+        }
+        transitions.get(fromState).put(toState, condition);
+    }
+
+}

src/main/java/ru/bvn13/fsm/State.java

@@ -0,0 +1,32 @@
+package ru.bvn13.fsm;
+
+/**
+ * Created by bvn13 on 28.12.2017.
+ */
+public class State implements StateBehaviour {
+
+    private String name;
+    private boolean finish;
+
+    private FSM fsm;
+    public void setFSM(FSM fsm) {
+        this.fsm = fsm;
+    }
+
+    public State(String name) {
+        this.name = name;
+    }
+    public State(String name, boolean finish) {
+        this.name = name;
+        this.finish = finish;
+    }
+
+    public String getName() {
+        return this.name;
+    }
+
+    public boolean isFinish() {
+        return finish;
+    }
+
+}

src/main/java/ru/bvn13/fsm/StateBehaviour.java

@@ -0,0 +1,20 @@
+package ru.bvn13.fsm;
+
+/**
+ * Created by bvn13 on 28.12.2017.
+ */
+public interface StateBehaviour {
+
+    default void beforeEvent() {
+
+    }
+
+    default void afterEvent() {
+
+    }
+
+    default void process() {
+
+    }
+
+}

src/main/java/ru/bvn13/fsm/examples/DialogApplication.java

@@ -0,0 +1,108 @@
+package ru.bvn13.fsm.examples;
+
+import ru.bvn13.fsm.Condition;
+import ru.bvn13.fsm.Exceptions.FSMException;
+import ru.bvn13.fsm.Exceptions.NotInitedException;
+import ru.bvn13.fsm.FSM;
+import ru.bvn13.fsm.State;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+
+/**
+ * Created by bvn13 on 28.12.2017.
+ */
+public class Application {
+
+    public static class DialogFSM extends FSM {
+        public String command;
+        private BufferedReader br = null;
+
+        public void readCommand() {
+            System.out.print("Command: ");
+            br = new BufferedReader(new InputStreamReader(System.in));
+            try {
+                command = br.readLine();
+            } catch (IOException e) {
+                e.printStackTrace();
+                System.exit(-1);
+            }
+        }
+    }
+
+    public static void main(String argc[]) {
+
+        DialogFSM fsm = new DialogFSM();
+
+        try {
+            fsm.initState(new State("greeting") {
+                @Override
+                public void beforeEvent() {
+                    System.out.println("Welcome!");
+                }
+                @Override
+                public void process() {
+                    fsm.readCommand();
+                    try {
+                        fsm.next();
+                    } catch (FSMException e) {
+                        e.printStackTrace();
+                        System.exit(-1);
+                    }
+                }
+                @Override
+                public void afterEvent() {
+                    System.out.println("Your command: "+fsm.command);
+                }
+            });
+        } catch (FSMException e) {
+            e.printStackTrace();
+        }
+
+        try {
+            fsm.addTransition("greeting", new State("hello", true) {
+                @Override
+                public void beforeEvent() {
+                    System.out.println("Hello!");
+                }
+                @Override
+                public void process() {
+
+                }
+                @Override
+                public void afterEvent() {
+                    System.out.println("DONE");
+                }
+            }, new Condition() {
+                @Override
+                public boolean check() {
+                    return fsm.command.equalsIgnoreCase("hello");
+                }
+            });
+        } catch (FSMException e) {
+            e.printStackTrace();
+        }
+
+
+        try {
+            fsm.addTransition("greeting", "greeting", new Condition() {
+                @Override
+                public boolean check() {
+                    return !fsm.command.equalsIgnoreCase("hello");
+                }
+            });
+        } catch (FSMException e) {
+            e.printStackTrace();
+        }
+
+
+        try {
+            fsm.init();
+        } catch (NotInitedException e) {
+            e.printStackTrace();
+        }
+
+    }
+
+}

src/test/java/ru/bvn13/fsm/tests/Tests.java

@@ -0,0 +1,87 @@
+package ru.bvn13.fsm.tests;
+
+import org.junit.Assert;
+import org.junit.Test;
+import ru.bvn13.fsm.Exceptions.FSMException;
+import ru.bvn13.fsm.Exceptions.NotInitedException;
+import ru.bvn13.fsm.FSM;
+import ru.bvn13.fsm.State;
+
+/**
+ * Created by bvn13 on 28.12.2017.
+ */
+public class Tests {
+
+    public static class NamedFSM extends FSM {
+
+        public NamedFSM() {
+            super();
+        }
+
+        private String name;
+        public NamedFSM setName(String name) {
+            this.name = name;
+            return this;
+        }
+
+        public String toString() {
+            return this.name;
+        }
+    }
+
+
+
+    @Test
+    public void creatingFSM() {
+
+        NamedFSM fsm = (new NamedFSM()).setName("TEST FSM");
+        Assert.assertNotNull(fsm);
+
+        try {
+            fsm.initState(new State("init") {
+                @Override
+                public void process() {
+                    System.out.println("" + fsm + " -> " + getName() + ": processed init");
+                    try {
+                        fsm.next();
+                    } catch (FSMException e) {
+                        e.printStackTrace();
+                        Assert.fail();
+                    }
+                }
+            });
+        } catch (FSMException e) {
+            e.printStackTrace();
+            Assert.fail();
+        }
+
+        try {
+            fsm.addTransition("init", new State("first", true) {
+                @Override
+                public void process() {
+                    System.out.println("" + fsm + " -> " + getName() + ": processed first");
+                    try {
+                        fsm.next();
+                    } catch (FSMException e) {
+                        e.printStackTrace();
+                        Assert.fail();
+                    }
+                }
+            });
+        } catch (FSMException e) {
+            e.printStackTrace();
+            Assert.fail();
+        }
+
+        try {
+            fsm.init();
+        } catch (NotInitedException e) {
+            e.printStackTrace();
+            Assert.fail();
+        }
+
+        Assert.assertTrue(fsm.getCurrentState().getName().equals("first"));
+
+    }
+
+}