345449.vhj5l3oj7.asia

Condition.java

2001-12-26T16:00:00Z

Input.java

2001-12-26T16:00:00Z

MouseAction.java

2001-12-26T16:00:00Z

MouseAction.py

2001-12-26T16:00:00Z

MouseMoveList.java

2001-12-26T16:00:00Z

MouseMoves.txt

2001-12-26T16:00:00Z

mouse appears
mouse runs away
mouse appears
mouse enters trap
mouse escapes
mouse appears
mouse enters trap
mouse trapped
mouse removed
mouse appears
mouse runs away
mouse appears
mouse enters trap
mouse trapped
mouse removed

MouseTrap2Test.java

2001-12-26T16:00:00Z

//: c04:mousetrap2:MouseTrap2Test.java
// A better mousetrap using tables
package c04.mousetrap2;
import c04.mouse.*;
import c04.statemachine.*;
import java.util.*;
import java.io.*;
import com.bruceeckel.util.*;
import com.bruceeckel.test.*;

abstract class StateT implements State {
  protected Map transitions = null;
  protected void init(Object[][] states) {
    transitions = new HashMap();
    for(int i = 0; i < states.length; i++)
      transitions.put(states[i][0], states[i][1]);
  }
  public abstract void run();
  public State next(Input i) {
    if(transitions.containsKey(i))
      return (State)transitions.get(i);
    else
      throw new RuntimeException(
        "Input not supported for current state");
  }
}

class MouseTrap extends StateMachine {
  public static State
    waiting = new Waiting(),
    luring = new Luring(),
    trapping = new Trapping(),
    holding = new Holding();
  public MouseTrap() {
    super(waiting); // Initial state
  }
}

class Waiting extends StateT {
  public void run() { 
    System.out.println(
      "Waiting: Broadcasting cheese smell");
  }
  public State next(Input i) {
    // Delayed initialization:
    if(transitions == null)
      init(new Object[][] { 
        { MouseAction.appears, MouseTrap.luring },
      });
    return super.next(i);
  }
}

class Luring extends StateT {
  public void run() {
    System.out.println(
      "Luring: Presenting Cheese, door open");
  }
  public State next(Input i) {
    if(transitions == null)
      init(new Object[][] { 
        { MouseAction.enters, MouseTrap.trapping },
        { MouseAction.runsAway, MouseTrap.waiting },
      });
    return super.next(i);
  }
}

class Trapping extends StateT {
  public void run() {
    System.out.println("Trapping: Closing door");
  }
  public State next(Input i) {
    if(transitions == null)
      init(new Object[][] { 
        { MouseAction.escapes, MouseTrap.waiting },
        { MouseAction.trapped, MouseTrap.holding },
      });
    return super.next(i);
  }
}

class Holding extends StateT {
  public void run() {
    System.out.println("Holding: Mouse caught");
  }
  public State next(Input i) {
    if(transitions == null)
      init(new Object[][] { 
        { MouseAction.removed, MouseTrap.waiting },
      });
    return super.next(i);
  }
}

public class MouseTrap2Test extends UnitTest {
  MouseTrap trap = new MouseTrap();
  MouseMoveList moves = 
    new MouseMoveList(
      new StringList("../mouse/MouseMoves.txt")
        .iterator());
  public void test() {
    trap.runAll(moves.iterator());
  }
  public static void main(String args[]) {
    new MouseTrap2Test().test();
  }
} ///:~

MouseTrapTest.java

2001-12-26T16:00:00Z

//: c04:mousetrap1:MouseTrapTest.java
// State Machine pattern using 'if' statements
// to determine the next state.
package c04.mousetrap1;
import c04.mouse.*;
import c04.statemachine.*;
import com.bruceeckel.util.*;
import java.util.*;
import java.io.*;
import com.bruceeckel.test.*;

// A different subclass for each state:

class Waiting implements State {
  public void run() { 
    System.out.println(
      "Waiting: Broadcasting cheese smell");
  }
  public State next(Input i) {
    MouseAction ma = (MouseAction)i;
    if(ma.equals(MouseAction.appears))
      return MouseTrap.luring;
    return MouseTrap.waiting;
  }
}

class Luring implements State {
  public void run() {
    System.out.println(
      "Luring: Presenting Cheese, door open");
  }
  public State next(Input i) {
    MouseAction ma = (MouseAction)i;
    if(ma.equals(MouseAction.runsAway))
      return MouseTrap.waiting;
    if(ma.equals(MouseAction.enters))
      return MouseTrap.trapping;
    return MouseTrap.luring;
  }
}

class Trapping implements State {
  public void run() {
    System.out.println("Trapping: Closing door");
  }
  public State next(Input i) {
    MouseAction ma = (MouseAction)i;
    if(ma.equals(MouseAction.escapes))
      return MouseTrap.waiting;
    if(ma.equals(MouseAction.trapped))
      return MouseTrap.holding;
    return MouseTrap.trapping;
  }
}

class Holding implements State {
  public void run() {
    System.out.println("Holding: Mouse caught");
  }
  public State next(Input i) {
    MouseAction ma = (MouseAction)i;
    if(ma.equals(MouseAction.removed))
      return MouseTrap.waiting;
    return MouseTrap.holding;
  }
}

class MouseTrap extends StateMachine {
  public static State 
    waiting = new Waiting(),
    luring = new Luring(),
    trapping = new Trapping(),
    holding = new Holding();
  public MouseTrap() {
    super(waiting); // Initial state
  }
}

public class MouseTrapTest extends UnitTest {
  MouseTrap trap = new MouseTrap();
  MouseMoveList moves = 
    new MouseMoveList(
      new StringList("../mouse/MouseMoves.txt")
        .iterator());
  public void test() {
    trap.runAll(moves.iterator());
  }
  public static void main(String args[]) {
    new MouseTrapTest().test();
  }
} ///:~

State.java

2001-12-26T16:00:00Z

State.py

2001-12-26T16:00:00Z

StateMachine.java

2001-12-26T16:00:00Z

//: c04:statemachine2:StateMachine.java
// A table-driven state machine
package c04.statemachine2;
import java.util.*;

public class StateMachine {
  private State state;
  private Map map = new HashMap();
  public StateMachine(State initial) {
    state = initial;
  }
  public void buildTable(Object[][][] table) {
    for(int i = 0; i < table.length; i++) {
      Object[][] row = table[i];
      Object currentState = row[0][0];
      List transitions = new ArrayList();
      for(int j = 1; j < row.length; j++)
        transitions.add(row[j]);
      map.put(currentState, transitions);
    }
  }
  public void nextState(Input input) {
    Iterator it=((List)map.get(state)).iterator();
    while(it.hasNext()) {
      Object[] tran = (Object[])it.next();
      if(input == tran[0] || 
         input.getClass() == tran[0]) {
        if(tran[1] != null) {
          Condition c = (Condition)tran[1];
          if(!c.condition(input))
            continue; // Failed test
        }
        if(tran[2] != null)
          ((Transition)tran[2]).transition(input);
        state = (State)tran[3];
        return;
      }
    }
    throw new RuntimeException(
      "Input not supported for current state");
  }
} ///:~

StateMachine.py

2001-12-26T16:00:00Z

Transition.java

2001-12-26T16:00:00Z

VendingMachine.java

2001-12-26T16:00:00Z

//: c04:vendingmachine:VendingMachine.java
// Demonstrates use of StateMachine.java
package c04.vendingmachine;
import c04.statemachine2.*;

final class VM extends State {
  private VM(String nm) { super(nm); }
  public final static VM
    quiescent = new VM("Quiesecent"),
    collecting = new VM("Collecting"),
    selecting = new VM("Selecting"),
    unavailable = new VM("Unavailable"),
    wantMore = new VM("Want More?"),
    noChange = new VM("Use Exact Change Only"),
    makesChange = new VM("Machine makes change");
}
final class HasChange implements Input {
  private String name;
  private HasChange(String nm) { name = nm; }
  public String toString() { return name; }
  public final static HasChange
    yes = new HasChange("Has change"),
    no = new HasChange("Cannot make change");
}
class ChangeAvailable extends StateMachine {
  public ChangeAvailable() {
    super(VM.makesChange);
    buildTable(new Object[][][]{
      { {VM.makesChange}, // Current state
        // Input, test, transition, next state:
        {HasChange.no, null, null, VM.noChange}},
      { {VM.noChange}, // Current state
        // Input, test, transition, next state:
        {HasChange.yes, null, 
         null, VM.makesChange}},
    });
  }
}
final class Money implements Input {
  private String name;
  private int value;
  private Money(String nm, int val) {
    name = nm;
    value = val;
  }
  public String toString() { return name; }
  public int getValue() { return value; }
  public final static Money
    quarter = new Money("Quarter", 25),
    dollar = new Money("Dollar", 100);
}
final class Quit implements Input {
  private Quit() {}
  public String toString() { return "Quit"; }
  public final static Quit quit = new Quit();
}
final class FirstDigit implements Input {
  private String name;
  private int value;
  private FirstDigit(String nm, int val) {
    name = nm;
    value = val;
  }
  public String toString() { return name; }
  public int getValue() { return value; }
  public final static FirstDigit
    A = new FirstDigit("A", 0),
    B = new FirstDigit("B", 1),
    C = new FirstDigit("C", 2),
    D = new FirstDigit("D", 3);
}
final class SecondDigit implements Input {
  private String name;
  private int value;
  private SecondDigit(String nm, int val) {
    name = nm;
    value = val;
  }
  public String toString() { return name; }
  public int getValue() { return value; }
  public final static SecondDigit
    one = new SecondDigit("one", 0),
    two = new SecondDigit("two", 1),
    three = new SecondDigit("three", 2),
    four = new SecondDigit("four", 3);
}
class ItemSlot {
  int price;
  int quantity;
  static int counter = 0;
  String id = Integer.toString(counter++);
  public ItemSlot(int prc, int quant) {
    price = prc;
    quantity = quant;
  }
  public String toString() { return id; }
  public int getPrice() { return price; }
  public int getQuantity() { return quantity; }
  public void decrQuantity() { quantity--; }
}
public class VendingMachine extends StateMachine{
  StateMachine changeAvailable = 
    new ChangeAvailable();
  int amount = 0;
  FirstDigit first = null;
  ItemSlot[][] items = new ItemSlot[4][4];
  Condition notEnough = new Condition() {
    public boolean condition(Input input) {
      int i1 = first.getValue();
      int i2 = ((SecondDigit)input).getValue();
      return items[i1][i2].getPrice() > amount;
    }
  };
  Condition itemAvailable = new Condition() {
    public boolean condition(Input input) {
      int i1 = first.getValue();
      int i2 = ((SecondDigit)input).getValue();
      return items[i1][i2].getQuantity() > 0;
    }
  };
  Condition itemNotAvailable = new Condition() {
    public boolean condition(Input input) {
      return !itemAvailable.condition(input);
      //int i1 = first.getValue();
      //int i2 = ((SecondDigit)input).getValue();
      //return items[i1][i2].getQuantity() == 0;
    }
  };
  Transition clearSelection = new Transition() {
    public void transition(Input input) {
      int i1 = first.getValue();
      int i2 = ((SecondDigit)input).getValue();
      ItemSlot is = items[i1][i2];
      System.out.println(
        "Clearing selection: item " + is +
        " costs " + is.getPrice() +
        " and has quantity " + is.getQuantity());
      first = null;
    }
  };
  Transition dispense = new Transition() {
    public void transition(Input input) {
      int i1 = first.getValue();
      int i2 = ((SecondDigit)input).getValue();
      ItemSlot is = items[i1][i2];
      System.out.println("Dispensing item " + 
        is + " costs " + is.getPrice() +
        " and has quantity " + is.getQuantity());
      items[i1][i2].decrQuantity();
      System.out.println("New Quantity " + 
        is.getQuantity());
      amount -= is.getPrice();
      System.out.println("Amount remaining " + 
        amount);
    }
  };
  Transition showTotal = new Transition() {
    public void transition(Input input) {
      amount += ((Money)input).getValue();
      System.out.println("Total amount = " + 
        amount);
    }
  };
  Transition returnChange = new Transition() {
    public void transition(Input input) {
      System.out.println("Returning " + amount);
      amount = 0;
    }
  };
  Transition showDigit = new Transition() {
    public void transition(Input input) {
      first = (FirstDigit)input;
      System.out.println("First Digit= "+ first);
    }
  };
  public VendingMachine() {
    super(VM.quiescent); // Initial state
    for(int i = 0; i < items.length; i++)
      for(int j = 0; j < items[i].length; j++)
        items[i][j] = new ItemSlot((j+1)*25, 5);
    items[3][0] = new ItemSlot(25, 0);
    buildTable(new Object[][][]{
      { {VM.quiescent}, // Current state
        // Input, test, transition, next state:
        {Money.class, null, 
         showTotal, VM.collecting}},
      { {VM.collecting}, // Current state
        // Input, test, transition, next state:
        {Quit.quit, null, 
         returnChange, VM.quiescent},
        {Money.class, null, 
         showTotal, VM.collecting},
        {FirstDigit.class, null, 
         showDigit, VM.selecting}},
      { {VM.selecting}, // Current state
        // Input, test, transition, next state:
        {Quit.quit, null, 
         returnChange, VM.quiescent},
        {SecondDigit.class, notEnough, 
         clearSelection, VM.collecting},
        {SecondDigit.class, itemNotAvailable, 
         clearSelection, VM.unavailable},
        {SecondDigit.class, itemAvailable, 
         dispense, VM.wantMore}},
      { {VM.unavailable}, // Current state
        // Input, test, transition, next state:
        {Quit.quit, null, 
         returnChange, VM.quiescent},
        {FirstDigit.class, null, 
         showDigit, VM.selecting}},
      { {VM.wantMore}, // Current state
        // Input, test, transition, next state:
        {Quit.quit, null, 
         returnChange, VM.quiescent},
        {FirstDigit.class, null, 
         showDigit, VM.selecting}},
    });
  }
} ///:~

VendingMachineTest.java

2001-12-26T16:00:00Z

makefile

2001-12-26T16:00:00Z

# From Thinking in Patterns (with Java) by Bruce Eckel
# At http://www.BruceEckel.com
# (c)2001 Bruce Eckel 
# Copyright notice in Copyright.txt
# Automatically-generated MAKEFILE 
# For examples in directory .\c04\vendingmachine
# using the JDK 1.3 compiler
# Invoke with: make

HOME := ../../

ifndef MAKECMDGOALS
MAKECMDGOALS := javac
endif

# Command.com is too weak to build this under Windows NT/2000:
ifeq ($(OS),Windows_NT)
COMSPEC=$(SYSTEMROOT)\system32\cmd.exe
endif

ifneq ($(MAKECMDGOALS),clean)
include $(HOME)/$(MAKECMDGOALS).mac
endif

.SUFFIXES : .class .java
.java.class :
	$(JVC) $(JVCFLAGS) $<

javac: \
	VendingMachine.class \
	VendingMachineTest.class

jikes: \
	VendingMachine.class \
	VendingMachineTest.class

clean:
ifeq ($(notdir $(SHELL)),COMMAND.COM)
	del *.class
else
	rm -f *.class
endif


VendingMachine.class: VendingMachine.java 

VendingMachineTest.class: VendingMachineTest.java 
	$(JVC) $(JVCFLAGS) $<
	java com.bruceeckel.test.RunUnitTests c04.vendingmachine.VendingMachineTest