001package headfirst.state.gumball; 002 003public class GumballMachine { 004 005 final static int SOLD_OUT = 0; 006 final static int NO_QUARTER = 1; 007 final static int HAS_QUARTER = 2; 008 final static int SOLD = 3; 009 010 int state = SOLD_OUT; 011 int count = 0; 012 013 public GumballMachine(int count) { 014 this.count = count; 015 if (count > 0) { 016 state = NO_QUARTER; 017 } 018 } 019 020 public void insertQuarter() { 021 if (state == HAS_QUARTER) { 022 System.out.println("You can't insert another quarter"); 023 } else if (state == NO_QUARTER) { 024 state = HAS_QUARTER; 025 System.out.println("You inserted a quarter"); 026 } else if (state == SOLD_OUT) { 027 System.out.println("You can't insert a quarter, the machine is sold out"); 028 } else if (state == SOLD) { 029 System.out.println("Please wait, we're already giving you a gumball"); 030 } 031 } 032 033 public void ejectQuarter() { 034 if (state == HAS_QUARTER) { 035 System.out.println("Quarter returned"); 036 state = NO_QUARTER; 037 } else if (state == NO_QUARTER) { 038 System.out.println("You haven't inserted a quarter"); 039 } else if (state == SOLD) { 040 System.out.println("Sorry, you already turned the crank"); 041 } else if (state == SOLD_OUT) { 042 System.out.println("You can't eject, you haven't inserted a quarter yet"); 043 } 044 } 045 046 047 048 049 public void turnCrank() { 050 if (state == SOLD) { 051 System.out.println("Turning twice doesn't get you another gumball!"); 052 } else if (state == NO_QUARTER) { 053 System.out.println("You turned but there's no quarter"); 054 } else if (state == SOLD_OUT) { 055 System.out.println("You turned, but there are no gumballs"); 056 } else if (state == HAS_QUARTER) { 057 System.out.println("You turned..."); 058 state = SOLD; 059 dispense(); 060 } 061 } 062 063 public void dispense() { 064 if (state == SOLD) { 065 System.out.println("A gumball comes rolling out the slot"); 066 count = count - 1; 067 if (count == 0) { 068 System.out.println("Oops, out of gumballs!"); 069 state = SOLD_OUT; 070 } else { 071 state = NO_QUARTER; 072 } 073 } else if (state == NO_QUARTER) { 074 System.out.println("You need to pay first"); 075 } else if (state == SOLD_OUT) { 076 System.out.println("No gumball dispensed"); 077 } else if (state == HAS_QUARTER) { 078 System.out.println("No gumball dispensed"); 079 } 080 } 081 082 public void refill(int numGumBalls) { 083 this.count = numGumBalls; 084 state = NO_QUARTER; 085 } 086 087 public String toString() { 088 StringBuilder result = new StringBuilder(); 089 result.append("\nMighty Gumball, Inc."); 090 result.append("\nJava-enabled Standing Gumball Model #2004\n"); 091 result.append("Inventory: " + count + " gumball"); 092 if (count != 1) { 093 result.append("s"); 094 } 095 result.append("\nMachine is "); 096 if (state == SOLD_OUT) { 097 result.append("sold out"); 098 } else if (state == NO_QUARTER) { 099 result.append("waiting for quarter"); 100 } else if (state == HAS_QUARTER) { 101 result.append("waiting for turn of crank"); 102 } else if (state == SOLD) { 103 result.append("delivering a gumball"); 104 } 105 result.append("\n"); 106 return result.toString(); 107 } 108} 109 110